https://peir.path.uab.edu/api.php?action=feedcontributions&feedformat=atom&user=Matthew+AndersonPathology Education Instructional Resource - User contributions [en]2026-04-06T13:59:57ZUser contributionsMediaWiki 1.31.1https://peir.path.uab.edu/index.php?title=Histologic:Chapter_2&diff=3280Histologic:Chapter 22014-07-26T16:55:07Z<p>Matthew Anderson: /* Slide 25: Spinal Cord (Thionin) */</p>
<hr />
<div>== Cells, Organelles, and Inclusions ==<br />
[[File:HistologicChapter2Cell.jpg|thumb|200px|Cell schematic]]<br />
To begin the study of cellular structure, you are asked to identify several kinds of cells, cellular specializations and inclusions of cells. Learn to distinguish between the nucleolus, the nucleus, and the cytoplasm of a cell. Observe the appearance of the chromatin, the position of the nucleus within the cell and the staining characteristics of the cytoplasm. Note the size of the cells, the density of similar cells, and their arrangement in the tissue. As you study the different cell types, keep in mind that sectioned material is being observed and that the appearance of the cell may vary depending on the plane of section.<br />
<br />
A cell usually contains only one nucleus, but some cells may be binucleate. The nucleus often conforms to the shape of the cell being spherical, ovoid, or elongated. Other nuclei may be crescent shaped or lobated. It can be flattened towards the base of the cell when the pressure from cytoplasmic constituents “pushes it” there. Nucleoli may or may not be present. In sectioned material, the nucleus or nucleolus may appear to be absent from a cell because they were not in the plane of sectioning. If the cell is in a phase of mitosis, the nucleus will appear different from nuclei of other non-mitotic cells of the tissue.<br />
<br />
The cytoplasm often exhibits modifications according to the specific functions of the cell or the tissue. Muscle cells have contractile myofibrils. Secretory cells of the salivary glands possess numerous secretory granules. Epithelial cells of the skin produce a protein called keratin for protection. The epithelial lining of the respiratory tract may possess cilia. White blood cells may contain primary and specific granules. Neurons possess neurofibrils, etc. The list is almost endless.<br />
<br />
NOTE: The objective of this first exercise is merely to gain an awareness of the varieties of cell sizes, cell shapes, cell types, cell staining characteristics and cell organelles or inclusions. You are not expected, at this time, to become familiar with the over-all structure of the tissues and organs where these cells are located. <br />
<br />
=== Microscopic Study: Architecture ===<br />
==== Slide 25: Spinal Cord (H&E) ====<br />
On slide 25, Spinal Cord (H&E) find under low power the cell bodies of multipolar neurons located in the two anterior horns of the gray matter (if the slide is held towards the light, the gray matter appears H-shaped). With medium power, identify a cell body containing a large pale nucleus and a darkly stained nucleolus. Study this cell under high power. The irregular, granular-like, basophilic staining masses within the cytoplasm are called Nissl bodies. They consist of free ribosomes and granular endoplasmic reticulum.<br />
<br />
<peir-vm>UAB-Histology-00025</peir-vm><br />
<br />
==== Slide 73: Spinal Ganglion (Silver) ====<br />
On slide 73, Spinal Ganglion (silver) identify the large cell bodies of the ganglion cells associated with the sensory root of spinal nerves. The cell bodies of these unipolar neurons range in size from 15μm to 100μm. Compare a number of ganglion cell bodies for size differences. The centrally located nuclei stain palely and appear as clear spaces in the middle of the granular cytoplasm. With careful observation you will see nuclei of much smaller cells immediately surrounding the cell bodies of the ganglion cells. These represent satellite cells. Note how much smaller they are than the nuclei of the ganglion cells.<br />
<br />
<peir-vm>UAB-Histology-00073</peir-vm><br />
<br />
==== Slide 149: Liver (H&E) ====<br />
On slide 149, Liver (H&E) observe that the hepatocytes (liver parenchymal cells) appear to be arranged as rows or cords of cells. Actually the tridimensional arrangement of these cells is in cellular sheets or plates which are separated by blood-filled spaces called sinusoids. Red blood corpuscles may be seen in some of the sinusoids. Note that cell boundaries can be distinctly seen between many of the liver cells. The polyhedral- shaped hepatocytes have round, centrally located nuclei containing one or more nucleoli and scattered clumps of chromatin. Binucleated hepatocytes can be found. Note the granularity of the eosinophilic staining cytoplasm<br />
<br />
<peir-vm>UAB-Histology-00149</peir-vm><br />
<br />
==== Slide 154: Pancreas (H&E) ====<br />
Slide 154, Pancreas (H&E) has cells which distinctly exhibit a difference between basophilic regions and acidophilic regions. After studying the cells with medium power, turn to high power to complete your study. Observe that the cell boundaries are indistinct. Note that the cytoplasm in the basal region of the acinar cells is basophilic. Here the ribonucleoproteins associated with rough endoplasmic reticulum and the large numbers of mitochondria are sufficiently dense to stain with the basic dye. Note, however, the red staining of the apical half of the acinar cells. This acidophilic staining cytoplasm contains numerous secretory granules that stain brightly with the eosin stain. The nuclei are basophilic staining as are the nuclei of all cells. Observe that the nuclei are characteristically located in the basal one-third of the cell. Nucleoli may be seen in many cells.<br />
<br />
<peir-vm>UAB-Histology-00154</peir-vm><br />
<br />
=== Microscopic Study: Cell Types ===<br />
==== Slide 2: Trachea (H&E) ==== <br />
[[File:HistologicChapter2Cilia.jpg|thumb|200px|Cilia schematic]]<br />
On slide 2, Trachea (H&E) identify the cilia on the tall cells of the pseudostratified columnar epithelium that line the lumen of the trachea. Each cilium is derived from a basal body, represented here in aggregate by the dark lines where the cilia attach to the cell. In some regions of this tissue the cilia are absent or the entire epithelium is missing. This is artifact.<br />
<br />
<peir-vm>UAB-Histology-00002</peir-vm><br />
<br />
==== Slide 89: Skeletal Muscle (H&E) ====<br />
On slide 89, Skeletal Muscle (H&E) identify muscle fibers cut in longitudinal section. Under high power note the striated appearance of the muscle cells. Although not readily visible, the cytoplasm of these cells contains myofibrils, the contractile elements of the cell. The arrangement of these myofibrils and their subunits, the myofilaments, impart the striated appearance to the muscle fibers.<br />
<br />
<peir-vm>UAB-Histology-00089</peir-vm><br />
<br />
==== Slide 31: Ileum (H&E) ====<br />
On slide 31, Ileum (H&E) identify with low power the villi projecting from one side of the tissue. With high power identify the tall cells (simple columnar cells) which cover these villi. On the free surface of these cells can be seen a dense line representing the striated border. This border consists of cytoplasmic processes termed microvilli that greatly increase the absorptive area of the small intestine. In light microscopy, the microvilli appear vertically striated so these projections form a “striated border.”<br />
<br />
<peir-vm>UAB-Histology-00031</peir-vm><br />
<br />
== Mitosis ==<br />
[[File:HistologicChapter2Mitosis.jpg|thumb|200px|Mitosis schematic]]<br />
Mitosis can be viewed as the means whereby identical genetic material, contained in the chromosomes, is distributed to two daughter nuclei. It can be divided into four stages, each characterized by certain features of nuclear or chromosome morphology and chromosome movement. The stages are arbitrary in that mitosis is a continuous process from its inception at prophase through the stages of metaphase and anaphase to the final stage of telophase. The nucleus of a cell that is not dividing is in the interphase stage.<br />
<br />
The number of mitotic figures in a tissue is an index of the rate of turnover of the component cells. In benign tumors, mitotic figures are few in numbers, whereas in malignant tumors, mitotic figures are more numerous and may include many bizarre forms. Hence, the recognition of mitotic figures is one criterion for the interpretation of various kinds of pathology of a tissue.<br />
<br />
=== Microscopic Study: Mitosis ===<br />
On slide 34, Mitosis (Iron H), are longitudinal sections of onion root tips in which cells have been fixed in various stages of mitosis. Learn to identify the characteristic arrangement of the chromatin in each state.<br />
<br />
==== Slide 34: Mitosis (Iron H) ====<br />
<peir-vm>UAB-Histology-00034</peir-vm><br />
<br />
{{Template:Histologic}}<br />
<br />
[[Category:Histologic]]</div>Matthew Andersonhttps://peir.path.uab.edu/index.php?title=Histologic:Chapter_19&diff=3279Histologic:Chapter 192014-07-21T23:26:24Z<p>Matthew Anderson: /* Endolymph and Perilymph */</p>
<hr />
<div>== Eye ==<br />
[[File:HistologicChapter19EyeDiagramUveitis.jpg|thumb|200px|Eye Diagram Uveitis]]<br />
=== Slide 285, Eye ===<br />
<br />
The eyeball is composed of three principal layers. <br />
<br />
The outer layer, or sclera, consists of dense fibrous connective tissue. The sclera is the "white" of the eye. The sclera is continuous with the transparent substantia propria of the cornea. The exposed front surface of the eye, including the cornea, is also covered by a thin, non-keratinized stratified squamous epithelium. <br />
<br />
The next layer, or choroid, consists of heavily pigmented loose connective tissue, including many melanocytes. The choroid is normally not visible behind the "white" of the sclera. The choroid is continuous with the iris; together the choroid and iris are called the uvea. A hole in this layer, the pupil, allows light to pass through.<br />
<br />
The inner layer, or retina, includes two portions. The neural retina is the photoreceptive, imaging-processing tissue. And the pigmented epithelium lies behind the neural retina; it also extends forward to line the iris. The lens is a specialized epithelial structure, suspended behind the pupil.<br />
<br />
The anterior chamber, the space between the iris and the cornea, is filled with aqueous humor. And the posterior chamber lies behind the iris.<br />
<br />
<peir-vm>UAB-Histology-00285</peir-vm><br />
<br />
=== Cornea ===<br />
<br />
The cornea consists of a thin surface epithelium (non-keratinized stratified squamous epithelium) overlying a layer of dense fibrous connective tissue, called the substantia propria. The epithelium of the cornea is continuous with the epithelium of the conjunctiva, both that of the eyeball itself and that of the inside of the eyelid; however the corneal epithelium is very thin (only a few cells thick) which leads to its transparency. The basement membrane between the corneal epithelium and the substantia propria is exceptionally thick and is called Bowman's membrane. Collagen of the cornea is organized into extremely regular layers. All the collagen fibers in one layer arranged in parallel, and alternating layers run in different directions. Corneal connective tissue has no blood vessels. Even though cells of the cornea are not very active metabolically, they still need oxygen and nutrients. As long as the cornea is in direct contact with air, oxygen can be absorbed directly and nutrients can diffuse into cornea from the aqueous humor. Cells of cornea are limited to fibroblasts and there are no blood vessels so there are no immune-system components; hence corneal tissue can be transplanted without need for careful tissue typing.<br />
<br />
At the inner surface of the cornea, a thick basal lamina (Decemet's membrane) separates the substantia propria from a layer of simple low cuboidal epithelium, called the corneal endothelium.<br />
<br />
Corneal epithelium contains free nerve endings. Since pain seems to be the only sensory modality that functions for corneal tissue, biologists long ago decided that free nerve endings elsewhere may also represent pain fibers.<br />
<br />
=== Iris ===<br />
<br />
Functionally, the iris is a rather simple opaque ring surrounding and controlling the diameter of its central aperture - the pupil. A ring of smooth muscle surrounding the pupil comprises the pupillary sphincter. The color of the iris ("eye color") results both from scattering of light by its trabecular meshwork of collagen fibers and from absorption of light by melanin granules in scattered melanocytes. Variations in eye color result from individual differences in the distribution and density of melanocytes and trabecular meshwork.<br />
<br />
=== Lens ===<br />
<br />
The lens is an isolated island of epithelial tissue with an anterior layer that is simple cuboidal and a posterior layer consisting of elongated cells, called lens fibers that are packed with lens protein. The shape of the lens (and hence its focal length) is determined by tension exerted through the suspensory fibers, controlled by smooth muscle of the ciliary body.<br />
<br />
=== Ciliary Body and Suspensory Fibers (zonules) ===<br />
<br />
Deep to the limbus (i.e., the site where the cornea meets the sclera), the choroid layer is thickened into the ciliary body. The ciliary body is a ring of smooth muscle fibers arranged concentrically around the opening in which the lens is suspended. The lens is suspended from the ciliary body by thin fibers of collagen, called suspensory fibers or zonules. Together, the ciliary body and suspensory fibers control the shape of the lens. The surface of the ciliary body is covered by an extension of the embryonic optic cup and small projections of this tissue from the ciliary processes, which secretes the aqueous humor. Aqueous humor flows from its site of formation in the posterior chamber (i.e., behind the iris) through the pupil into the anterior chamber. From there it drains into the canal of Schlemm and hence into venous drainage. An imbalance between the formation and drainage of aqueous humor can create increased pressure leading to glaucoma.<br />
<br />
=== Retina ===<br />
[[File:HistologicChapter19Retina.Jpg|thumb|200px|Retina]]<br />
The retina consists of two distinct layers, the neural retina (often called simply "the retina") and the pigmented epithelium.<br />
<br />
The neural retina is the light-sensitive tissue of the eye. The photoreceptor cells (rods and cones) are located in the back of the retina, so light must pass through all of the layers of the neural retina before getting to the receptors. And the blood vessels which serve the retina are spread across the front surface, so light on its way to the receptors must also pass by the blood vessels. The nerve fibers which eventually travel from the eye through the optic nerve must pass through the layers of the retina, leaving a "blind spot" where they do so. <br />
<br />
Cells comprising the neural retina form several layers.<br />
<br />
*The innermost layer is the inner limiting membrane, a basal lamina separating nervous tissue of the retina from connective tissue of the vitreous humor. <br />
*The layer of nerve fibers contains axons from ganglion cells which travel across the retina to the optic nerve and hence past the optic chiasm into the optic tract and into lateral geniculate nucleus of the thalamus.<br />
*The ganglion cell layer contains the cell bodies of ganglion cells, the cells whose axons project to the brain.<br />
*The inner plexiform layer contains dendrites of ganglion cells synapsing with axons of bipolar cells.<br />
*The inner nuclear layer contains the cell bodies of bipolar cells<br />
*The outer plexiform layer contains dendrites of bipolar cells synapsing with axons of photoreceptor cells.<br />
*The outer nuclear layer contains the cell bodies of receptor cells.<br />
*Between the outer nuclear layer and the receptor layer is the site of the outer limiting membrane, a basal lamina bounding the neural retina. <br />
<br />
The outer segments (rods and cones) of the receptor cells penetrate the outer membrane to contact the pigmented epithelium.<br />
<br />
*The receptor layer contains the photoreceptive outer segments (rods and cones) of receptor cells.<br />
<br />
Photoreceptor cells come in two types, rods and cones. Rods are sensitive to dim light and provide night vision. Rods are more numerous in the peripheral retina. Cones need brighter light and provide daytime color vision. Cones are more prevalent in the vicinity of the fovea.<br />
<br />
== Ear ==<br />
[[File:HistologicChapter19EarDiagram.jpg|thumb|200px|Ear Diagram]]<br />
The ear has three distinct regions -- outer ear, middle ear, and inner ear.<br />
<br />
The outer ear includes the pinna (the visible ear, consisting mostly of skin and cartilage) and the ear canal. The latter is lined by keratinized stratified squamous epithelium. This lining differs from skin by the presence of specialized ceruminous (ear-wax) glands.<br />
<br />
The middle ear is basically a space, communicating via the eustacian tube with the oropharynx. It is lined by a very thin non-keratinized stratified squamous epithelium. Spanning the space of the middle ear are the three middle ear bones, the malleus (hammer), incus (anvil), and stapes (stirrup).<br />
<br />
The eardrum is a thin membrane separating the outer ear from the middle ear. It is sandwich of tissues, with keratinized stratified squamous epithelium facing the outer ear, non-keratinized stratified squamous epithelium facing the middle ear, and a very thin layer of connective tissue in between.<br />
<br />
The inner ear is the portion of the ear which contains sensory receptors. <br />
<br />
=== Inner Ear ===<br />
<br />
The inner ear consists of fluid-filled sacs (membranous labyrinth) that lie in cavities in the temporal bone of the skull (bony or osseous labyrinth). The inner ear contains sense organs serving both balance and hearing. Head position (i.e., gravity; also linear acceleration) is sensed by the otolith organs of the saccule and utricle. Head rotation (i.e., angular acceleration) is sensed by the cristae ampularis of the semicircular canals. And hearing is sensed by the organ of Corti within the scala media of the cochlea. All of these senses of the inner ear utilize the same mechanoreceptor cell type: epithelial hair cells. <br />
<br />
Hair cells, the specialized mechanoreceptor cells of the auditory and vestibular systems, are found in several positions along the chambers and passageways of the membranous labyrinth. Hair cells are basically columnar epithelial cells. At the apical end of each hair cell is a set of "hairs" (cytoplasmic projections, kinocilium and stereocilia) embedded in a mass of extracellular jelly. At the basal end of each hair cell are synapses onto sensory axons. A hair cell responds when movement of the extracellular jelly displaces its kinocilium and stereocilia. Displacement of the kinocilium and stereocilia alters conductance of ion channels, in turn affecting release of neurotransmitter onto the associated sensory axon. (These axons project along the auditory and vestibular nerves, cranial nerve VIII).<br />
<br />
=== Semicircular Canals ===<br />
<br />
Each semicircular canal of the bony labyrinth is a hollow passageway looping out from and back to the vestibule. Within each of these passageways is a semicircular canal of the membranous labyrinth. At one end of each membranous semicircular canal is a small enlargement called the ampulla. Within each ampulla is a ridge or "crest" called the crista that is covered with hair cells. A small mass of jelly, called the cupola ("cap") rests on top of the hair cells of the crista. The hair cells of the ampullae respond to angular acceleration (i.e., rotation of the head) <br />
<br />
There are three semicircular canals in each ear, oriented in three mutually-perpendicular planes. Rotation of the head in any direction will cause inertial fluid movement in one or more of the semicircular canals. <br />
<br />
=== Cochlea ===<br />
[[File:HistologicChapter19CochlearNerve.jpg|thumb|200px|Cochlear Nerve]]<br />
==== Slide 286, Ear Cochlea ====<br />
<br />
The cochlea houses an elaborate configuration of membranous labyrinth and hair cells, called the organ of Corti, designed for auditory reception. The basic shape of the cochlea is that of a snail-shell, or tapering helix. The spiraling tunnel that forms the cochlea of the bony labyrinth is divided into three distinct channels by portions of the membranous labyrinth attached to bony ridges. The central column of the helical cochlea contains axons serving the organ of Corti on their way to the auditory nerve. <br />
<br />
<peir-vm>UAB-Histology-00286</peir-vm><br />
<br />
=== Organ of Corti ===<br />
<br />
The organ of Corti is an elaborate structure with more named parts than the rest of inner ear. The organ of Corti is a long strip of tissue that extends the length of the scala media, from the base of the cochlea to its apex. Within the complex strip of tissue that comprises the organ of Corti are specialized sensory hair cells. The whole organ of Corti rests on the basilar membrane which supports the basal ends of the hair cells in the organ of Corti. The apical ends of hair cells touch the tectorial membrane, a "shelf" of jelly that is supported immovably on the spiral lamina. When the basilar membrane flexes in respond to sound waves (i.e., pressure waves delivered to inner-ear fluid by the middle-ear ossicles), the organ of Corti, including its hair cells, also moves. Thus, when the basilar membrane is moved by pressure waves (i.e., sound), the hair cells move relative to the tectorial membrane, causing stimulatory deflection of the apical ends of the hair cells.<br />
<br />
=== Endolymph and Perilymph ===<br />
[[File:HistologicChapter19CristaAmpullaris.jpg|thumb|200px|Crista Ampullaris]]<br />
The membranous labyrinth is filled with endolymph and is surrounded by perilymph. Endolymph is a unique fluid, with high K+ concentration and very low Na+ concentration. This endolymph provides the proper ionic environment for hair cell function. Endolymph is secreted by cells of the stria vascularis, along the scala media of the cochlea. <br />
<br />
In the vestibular system (surrounding the saccule, utricle, and semicircular canals), perilymph simply provides a cushioning support for the membranous labyrinth.<br />
<br />
In the cochlea, perilymph of the ascending scala vestibuli and the descending scala tympani conveys pressure waves (sound) across the scala media. Pressure waves flex the basilar membrane and thereby stimulate hair cells of the organ of Corti.<br />
<br />
<br />
{{Template:Histologic}}<br />
<br />
[[Category:Histologic]]</div>Matthew Andersonhttps://peir.path.uab.edu/index.php?title=File:HistologicChapter19CristaAmpullaris.jpg&diff=3278File:HistologicChapter19CristaAmpullaris.jpg2014-07-21T23:25:46Z<p>Matthew Anderson: </p>
<hr />
<div></div>Matthew Andersonhttps://peir.path.uab.edu/index.php?title=Histologic:Chapter_19&diff=3277Histologic:Chapter 192014-07-21T23:24:27Z<p>Matthew Anderson: /* Cochlea */</p>
<hr />
<div>== Eye ==<br />
[[File:HistologicChapter19EyeDiagramUveitis.jpg|thumb|200px|Eye Diagram Uveitis]]<br />
=== Slide 285, Eye ===<br />
<br />
The eyeball is composed of three principal layers. <br />
<br />
The outer layer, or sclera, consists of dense fibrous connective tissue. The sclera is the "white" of the eye. The sclera is continuous with the transparent substantia propria of the cornea. The exposed front surface of the eye, including the cornea, is also covered by a thin, non-keratinized stratified squamous epithelium. <br />
<br />
The next layer, or choroid, consists of heavily pigmented loose connective tissue, including many melanocytes. The choroid is normally not visible behind the "white" of the sclera. The choroid is continuous with the iris; together the choroid and iris are called the uvea. A hole in this layer, the pupil, allows light to pass through.<br />
<br />
The inner layer, or retina, includes two portions. The neural retina is the photoreceptive, imaging-processing tissue. And the pigmented epithelium lies behind the neural retina; it also extends forward to line the iris. The lens is a specialized epithelial structure, suspended behind the pupil.<br />
<br />
The anterior chamber, the space between the iris and the cornea, is filled with aqueous humor. And the posterior chamber lies behind the iris.<br />
<br />
<peir-vm>UAB-Histology-00285</peir-vm><br />
<br />
=== Cornea ===<br />
<br />
The cornea consists of a thin surface epithelium (non-keratinized stratified squamous epithelium) overlying a layer of dense fibrous connective tissue, called the substantia propria. The epithelium of the cornea is continuous with the epithelium of the conjunctiva, both that of the eyeball itself and that of the inside of the eyelid; however the corneal epithelium is very thin (only a few cells thick) which leads to its transparency. The basement membrane between the corneal epithelium and the substantia propria is exceptionally thick and is called Bowman's membrane. Collagen of the cornea is organized into extremely regular layers. All the collagen fibers in one layer arranged in parallel, and alternating layers run in different directions. Corneal connective tissue has no blood vessels. Even though cells of the cornea are not very active metabolically, they still need oxygen and nutrients. As long as the cornea is in direct contact with air, oxygen can be absorbed directly and nutrients can diffuse into cornea from the aqueous humor. Cells of cornea are limited to fibroblasts and there are no blood vessels so there are no immune-system components; hence corneal tissue can be transplanted without need for careful tissue typing.<br />
<br />
At the inner surface of the cornea, a thick basal lamina (Decemet's membrane) separates the substantia propria from a layer of simple low cuboidal epithelium, called the corneal endothelium.<br />
<br />
Corneal epithelium contains free nerve endings. Since pain seems to be the only sensory modality that functions for corneal tissue, biologists long ago decided that free nerve endings elsewhere may also represent pain fibers.<br />
<br />
=== Iris ===<br />
<br />
Functionally, the iris is a rather simple opaque ring surrounding and controlling the diameter of its central aperture - the pupil. A ring of smooth muscle surrounding the pupil comprises the pupillary sphincter. The color of the iris ("eye color") results both from scattering of light by its trabecular meshwork of collagen fibers and from absorption of light by melanin granules in scattered melanocytes. Variations in eye color result from individual differences in the distribution and density of melanocytes and trabecular meshwork.<br />
<br />
=== Lens ===<br />
<br />
The lens is an isolated island of epithelial tissue with an anterior layer that is simple cuboidal and a posterior layer consisting of elongated cells, called lens fibers that are packed with lens protein. The shape of the lens (and hence its focal length) is determined by tension exerted through the suspensory fibers, controlled by smooth muscle of the ciliary body.<br />
<br />
=== Ciliary Body and Suspensory Fibers (zonules) ===<br />
<br />
Deep to the limbus (i.e., the site where the cornea meets the sclera), the choroid layer is thickened into the ciliary body. The ciliary body is a ring of smooth muscle fibers arranged concentrically around the opening in which the lens is suspended. The lens is suspended from the ciliary body by thin fibers of collagen, called suspensory fibers or zonules. Together, the ciliary body and suspensory fibers control the shape of the lens. The surface of the ciliary body is covered by an extension of the embryonic optic cup and small projections of this tissue from the ciliary processes, which secretes the aqueous humor. Aqueous humor flows from its site of formation in the posterior chamber (i.e., behind the iris) through the pupil into the anterior chamber. From there it drains into the canal of Schlemm and hence into venous drainage. An imbalance between the formation and drainage of aqueous humor can create increased pressure leading to glaucoma.<br />
<br />
=== Retina ===<br />
[[File:HistologicChapter19Retina.Jpg|thumb|200px|Retina]]<br />
The retina consists of two distinct layers, the neural retina (often called simply "the retina") and the pigmented epithelium.<br />
<br />
The neural retina is the light-sensitive tissue of the eye. The photoreceptor cells (rods and cones) are located in the back of the retina, so light must pass through all of the layers of the neural retina before getting to the receptors. And the blood vessels which serve the retina are spread across the front surface, so light on its way to the receptors must also pass by the blood vessels. The nerve fibers which eventually travel from the eye through the optic nerve must pass through the layers of the retina, leaving a "blind spot" where they do so. <br />
<br />
Cells comprising the neural retina form several layers.<br />
<br />
*The innermost layer is the inner limiting membrane, a basal lamina separating nervous tissue of the retina from connective tissue of the vitreous humor. <br />
*The layer of nerve fibers contains axons from ganglion cells which travel across the retina to the optic nerve and hence past the optic chiasm into the optic tract and into lateral geniculate nucleus of the thalamus.<br />
*The ganglion cell layer contains the cell bodies of ganglion cells, the cells whose axons project to the brain.<br />
*The inner plexiform layer contains dendrites of ganglion cells synapsing with axons of bipolar cells.<br />
*The inner nuclear layer contains the cell bodies of bipolar cells<br />
*The outer plexiform layer contains dendrites of bipolar cells synapsing with axons of photoreceptor cells.<br />
*The outer nuclear layer contains the cell bodies of receptor cells.<br />
*Between the outer nuclear layer and the receptor layer is the site of the outer limiting membrane, a basal lamina bounding the neural retina. <br />
<br />
The outer segments (rods and cones) of the receptor cells penetrate the outer membrane to contact the pigmented epithelium.<br />
<br />
*The receptor layer contains the photoreceptive outer segments (rods and cones) of receptor cells.<br />
<br />
Photoreceptor cells come in two types, rods and cones. Rods are sensitive to dim light and provide night vision. Rods are more numerous in the peripheral retina. Cones need brighter light and provide daytime color vision. Cones are more prevalent in the vicinity of the fovea.<br />
<br />
== Ear ==<br />
[[File:HistologicChapter19EarDiagram.jpg|thumb|200px|Ear Diagram]]<br />
The ear has three distinct regions -- outer ear, middle ear, and inner ear.<br />
<br />
The outer ear includes the pinna (the visible ear, consisting mostly of skin and cartilage) and the ear canal. The latter is lined by keratinized stratified squamous epithelium. This lining differs from skin by the presence of specialized ceruminous (ear-wax) glands.<br />
<br />
The middle ear is basically a space, communicating via the eustacian tube with the oropharynx. It is lined by a very thin non-keratinized stratified squamous epithelium. Spanning the space of the middle ear are the three middle ear bones, the malleus (hammer), incus (anvil), and stapes (stirrup).<br />
<br />
The eardrum is a thin membrane separating the outer ear from the middle ear. It is sandwich of tissues, with keratinized stratified squamous epithelium facing the outer ear, non-keratinized stratified squamous epithelium facing the middle ear, and a very thin layer of connective tissue in between.<br />
<br />
The inner ear is the portion of the ear which contains sensory receptors. <br />
<br />
=== Inner Ear ===<br />
<br />
The inner ear consists of fluid-filled sacs (membranous labyrinth) that lie in cavities in the temporal bone of the skull (bony or osseous labyrinth). The inner ear contains sense organs serving both balance and hearing. Head position (i.e., gravity; also linear acceleration) is sensed by the otolith organs of the saccule and utricle. Head rotation (i.e., angular acceleration) is sensed by the cristae ampularis of the semicircular canals. And hearing is sensed by the organ of Corti within the scala media of the cochlea. All of these senses of the inner ear utilize the same mechanoreceptor cell type: epithelial hair cells. <br />
<br />
Hair cells, the specialized mechanoreceptor cells of the auditory and vestibular systems, are found in several positions along the chambers and passageways of the membranous labyrinth. Hair cells are basically columnar epithelial cells. At the apical end of each hair cell is a set of "hairs" (cytoplasmic projections, kinocilium and stereocilia) embedded in a mass of extracellular jelly. At the basal end of each hair cell are synapses onto sensory axons. A hair cell responds when movement of the extracellular jelly displaces its kinocilium and stereocilia. Displacement of the kinocilium and stereocilia alters conductance of ion channels, in turn affecting release of neurotransmitter onto the associated sensory axon. (These axons project along the auditory and vestibular nerves, cranial nerve VIII).<br />
<br />
=== Semicircular Canals ===<br />
<br />
Each semicircular canal of the bony labyrinth is a hollow passageway looping out from and back to the vestibule. Within each of these passageways is a semicircular canal of the membranous labyrinth. At one end of each membranous semicircular canal is a small enlargement called the ampulla. Within each ampulla is a ridge or "crest" called the crista that is covered with hair cells. A small mass of jelly, called the cupola ("cap") rests on top of the hair cells of the crista. The hair cells of the ampullae respond to angular acceleration (i.e., rotation of the head) <br />
<br />
There are three semicircular canals in each ear, oriented in three mutually-perpendicular planes. Rotation of the head in any direction will cause inertial fluid movement in one or more of the semicircular canals. <br />
<br />
=== Cochlea ===<br />
[[File:HistologicChapter19CochlearNerve.jpg|thumb|200px|Cochlear Nerve]]<br />
==== Slide 286, Ear Cochlea ====<br />
<br />
The cochlea houses an elaborate configuration of membranous labyrinth and hair cells, called the organ of Corti, designed for auditory reception. The basic shape of the cochlea is that of a snail-shell, or tapering helix. The spiraling tunnel that forms the cochlea of the bony labyrinth is divided into three distinct channels by portions of the membranous labyrinth attached to bony ridges. The central column of the helical cochlea contains axons serving the organ of Corti on their way to the auditory nerve. <br />
<br />
<peir-vm>UAB-Histology-00286</peir-vm><br />
<br />
=== Organ of Corti ===<br />
<br />
The organ of Corti is an elaborate structure with more named parts than the rest of inner ear. The organ of Corti is a long strip of tissue that extends the length of the scala media, from the base of the cochlea to its apex. Within the complex strip of tissue that comprises the organ of Corti are specialized sensory hair cells. The whole organ of Corti rests on the basilar membrane which supports the basal ends of the hair cells in the organ of Corti. The apical ends of hair cells touch the tectorial membrane, a "shelf" of jelly that is supported immovably on the spiral lamina. When the basilar membrane flexes in respond to sound waves (i.e., pressure waves delivered to inner-ear fluid by the middle-ear ossicles), the organ of Corti, including its hair cells, also moves. Thus, when the basilar membrane is moved by pressure waves (i.e., sound), the hair cells move relative to the tectorial membrane, causing stimulatory deflection of the apical ends of the hair cells.<br />
<br />
=== Endolymph and Perilymph ===<br />
<br />
The membranous labyrinth is filled with endolymph and is surrounded by perilymph. Endolymph is a unique fluid, with high K+ concentration and very low Na+ concentration. This endolymph provides the proper ionic environment for hair cell function. Endolymph is secreted by cells of the stria vascularis, along the scala media of the cochlea. <br />
<br />
In the vestibular system (surrounding the saccule, utricle, and semicircular canals), perilymph simply provides a cushioning support for the membranous labyrinth.<br />
<br />
In the cochlea, perilymph of the ascending scala vestibuli and the descending scala tympani conveys pressure waves (sound) across the scala media. Pressure waves flex the basilar membrane and thereby stimulate hair cells of the organ of Corti.<br />
<br />
<br />
{{Template:Histologic}}<br />
<br />
[[Category:Histologic]]</div>Matthew Andersonhttps://peir.path.uab.edu/index.php?title=File:HistologicChapter19CochlearNerve.jpg&diff=3276File:HistologicChapter19CochlearNerve.jpg2014-07-21T23:24:09Z<p>Matthew Anderson: </p>
<hr />
<div></div>Matthew Andersonhttps://peir.path.uab.edu/index.php?title=Histologic:Chapter_19&diff=3275Histologic:Chapter 192014-07-21T23:22:40Z<p>Matthew Anderson: /* Ear */</p>
<hr />
<div>== Eye ==<br />
[[File:HistologicChapter19EyeDiagramUveitis.jpg|thumb|200px|Eye Diagram Uveitis]]<br />
=== Slide 285, Eye ===<br />
<br />
The eyeball is composed of three principal layers. <br />
<br />
The outer layer, or sclera, consists of dense fibrous connective tissue. The sclera is the "white" of the eye. The sclera is continuous with the transparent substantia propria of the cornea. The exposed front surface of the eye, including the cornea, is also covered by a thin, non-keratinized stratified squamous epithelium. <br />
<br />
The next layer, or choroid, consists of heavily pigmented loose connective tissue, including many melanocytes. The choroid is normally not visible behind the "white" of the sclera. The choroid is continuous with the iris; together the choroid and iris are called the uvea. A hole in this layer, the pupil, allows light to pass through.<br />
<br />
The inner layer, or retina, includes two portions. The neural retina is the photoreceptive, imaging-processing tissue. And the pigmented epithelium lies behind the neural retina; it also extends forward to line the iris. The lens is a specialized epithelial structure, suspended behind the pupil.<br />
<br />
The anterior chamber, the space between the iris and the cornea, is filled with aqueous humor. And the posterior chamber lies behind the iris.<br />
<br />
<peir-vm>UAB-Histology-00285</peir-vm><br />
<br />
=== Cornea ===<br />
<br />
The cornea consists of a thin surface epithelium (non-keratinized stratified squamous epithelium) overlying a layer of dense fibrous connective tissue, called the substantia propria. The epithelium of the cornea is continuous with the epithelium of the conjunctiva, both that of the eyeball itself and that of the inside of the eyelid; however the corneal epithelium is very thin (only a few cells thick) which leads to its transparency. The basement membrane between the corneal epithelium and the substantia propria is exceptionally thick and is called Bowman's membrane. Collagen of the cornea is organized into extremely regular layers. All the collagen fibers in one layer arranged in parallel, and alternating layers run in different directions. Corneal connective tissue has no blood vessels. Even though cells of the cornea are not very active metabolically, they still need oxygen and nutrients. As long as the cornea is in direct contact with air, oxygen can be absorbed directly and nutrients can diffuse into cornea from the aqueous humor. Cells of cornea are limited to fibroblasts and there are no blood vessels so there are no immune-system components; hence corneal tissue can be transplanted without need for careful tissue typing.<br />
<br />
At the inner surface of the cornea, a thick basal lamina (Decemet's membrane) separates the substantia propria from a layer of simple low cuboidal epithelium, called the corneal endothelium.<br />
<br />
Corneal epithelium contains free nerve endings. Since pain seems to be the only sensory modality that functions for corneal tissue, biologists long ago decided that free nerve endings elsewhere may also represent pain fibers.<br />
<br />
=== Iris ===<br />
<br />
Functionally, the iris is a rather simple opaque ring surrounding and controlling the diameter of its central aperture - the pupil. A ring of smooth muscle surrounding the pupil comprises the pupillary sphincter. The color of the iris ("eye color") results both from scattering of light by its trabecular meshwork of collagen fibers and from absorption of light by melanin granules in scattered melanocytes. Variations in eye color result from individual differences in the distribution and density of melanocytes and trabecular meshwork.<br />
<br />
=== Lens ===<br />
<br />
The lens is an isolated island of epithelial tissue with an anterior layer that is simple cuboidal and a posterior layer consisting of elongated cells, called lens fibers that are packed with lens protein. The shape of the lens (and hence its focal length) is determined by tension exerted through the suspensory fibers, controlled by smooth muscle of the ciliary body.<br />
<br />
=== Ciliary Body and Suspensory Fibers (zonules) ===<br />
<br />
Deep to the limbus (i.e., the site where the cornea meets the sclera), the choroid layer is thickened into the ciliary body. The ciliary body is a ring of smooth muscle fibers arranged concentrically around the opening in which the lens is suspended. The lens is suspended from the ciliary body by thin fibers of collagen, called suspensory fibers or zonules. Together, the ciliary body and suspensory fibers control the shape of the lens. The surface of the ciliary body is covered by an extension of the embryonic optic cup and small projections of this tissue from the ciliary processes, which secretes the aqueous humor. Aqueous humor flows from its site of formation in the posterior chamber (i.e., behind the iris) through the pupil into the anterior chamber. From there it drains into the canal of Schlemm and hence into venous drainage. An imbalance between the formation and drainage of aqueous humor can create increased pressure leading to glaucoma.<br />
<br />
=== Retina ===<br />
[[File:HistologicChapter19Retina.Jpg|thumb|200px|Retina]]<br />
The retina consists of two distinct layers, the neural retina (often called simply "the retina") and the pigmented epithelium.<br />
<br />
The neural retina is the light-sensitive tissue of the eye. The photoreceptor cells (rods and cones) are located in the back of the retina, so light must pass through all of the layers of the neural retina before getting to the receptors. And the blood vessels which serve the retina are spread across the front surface, so light on its way to the receptors must also pass by the blood vessels. The nerve fibers which eventually travel from the eye through the optic nerve must pass through the layers of the retina, leaving a "blind spot" where they do so. <br />
<br />
Cells comprising the neural retina form several layers.<br />
<br />
*The innermost layer is the inner limiting membrane, a basal lamina separating nervous tissue of the retina from connective tissue of the vitreous humor. <br />
*The layer of nerve fibers contains axons from ganglion cells which travel across the retina to the optic nerve and hence past the optic chiasm into the optic tract and into lateral geniculate nucleus of the thalamus.<br />
*The ganglion cell layer contains the cell bodies of ganglion cells, the cells whose axons project to the brain.<br />
*The inner plexiform layer contains dendrites of ganglion cells synapsing with axons of bipolar cells.<br />
*The inner nuclear layer contains the cell bodies of bipolar cells<br />
*The outer plexiform layer contains dendrites of bipolar cells synapsing with axons of photoreceptor cells.<br />
*The outer nuclear layer contains the cell bodies of receptor cells.<br />
*Between the outer nuclear layer and the receptor layer is the site of the outer limiting membrane, a basal lamina bounding the neural retina. <br />
<br />
The outer segments (rods and cones) of the receptor cells penetrate the outer membrane to contact the pigmented epithelium.<br />
<br />
*The receptor layer contains the photoreceptive outer segments (rods and cones) of receptor cells.<br />
<br />
Photoreceptor cells come in two types, rods and cones. Rods are sensitive to dim light and provide night vision. Rods are more numerous in the peripheral retina. Cones need brighter light and provide daytime color vision. Cones are more prevalent in the vicinity of the fovea.<br />
<br />
== Ear ==<br />
[[File:HistologicChapter19EarDiagram.jpg|thumb|200px|Ear Diagram]]<br />
The ear has three distinct regions -- outer ear, middle ear, and inner ear.<br />
<br />
The outer ear includes the pinna (the visible ear, consisting mostly of skin and cartilage) and the ear canal. The latter is lined by keratinized stratified squamous epithelium. This lining differs from skin by the presence of specialized ceruminous (ear-wax) glands.<br />
<br />
The middle ear is basically a space, communicating via the eustacian tube with the oropharynx. It is lined by a very thin non-keratinized stratified squamous epithelium. Spanning the space of the middle ear are the three middle ear bones, the malleus (hammer), incus (anvil), and stapes (stirrup).<br />
<br />
The eardrum is a thin membrane separating the outer ear from the middle ear. It is sandwich of tissues, with keratinized stratified squamous epithelium facing the outer ear, non-keratinized stratified squamous epithelium facing the middle ear, and a very thin layer of connective tissue in between.<br />
<br />
The inner ear is the portion of the ear which contains sensory receptors. <br />
<br />
=== Inner Ear ===<br />
<br />
The inner ear consists of fluid-filled sacs (membranous labyrinth) that lie in cavities in the temporal bone of the skull (bony or osseous labyrinth). The inner ear contains sense organs serving both balance and hearing. Head position (i.e., gravity; also linear acceleration) is sensed by the otolith organs of the saccule and utricle. Head rotation (i.e., angular acceleration) is sensed by the cristae ampularis of the semicircular canals. And hearing is sensed by the organ of Corti within the scala media of the cochlea. All of these senses of the inner ear utilize the same mechanoreceptor cell type: epithelial hair cells. <br />
<br />
Hair cells, the specialized mechanoreceptor cells of the auditory and vestibular systems, are found in several positions along the chambers and passageways of the membranous labyrinth. Hair cells are basically columnar epithelial cells. At the apical end of each hair cell is a set of "hairs" (cytoplasmic projections, kinocilium and stereocilia) embedded in a mass of extracellular jelly. At the basal end of each hair cell are synapses onto sensory axons. A hair cell responds when movement of the extracellular jelly displaces its kinocilium and stereocilia. Displacement of the kinocilium and stereocilia alters conductance of ion channels, in turn affecting release of neurotransmitter onto the associated sensory axon. (These axons project along the auditory and vestibular nerves, cranial nerve VIII).<br />
<br />
=== Semicircular Canals ===<br />
<br />
Each semicircular canal of the bony labyrinth is a hollow passageway looping out from and back to the vestibule. Within each of these passageways is a semicircular canal of the membranous labyrinth. At one end of each membranous semicircular canal is a small enlargement called the ampulla. Within each ampulla is a ridge or "crest" called the crista that is covered with hair cells. A small mass of jelly, called the cupola ("cap") rests on top of the hair cells of the crista. The hair cells of the ampullae respond to angular acceleration (i.e., rotation of the head) <br />
<br />
There are three semicircular canals in each ear, oriented in three mutually-perpendicular planes. Rotation of the head in any direction will cause inertial fluid movement in one or more of the semicircular canals. <br />
<br />
=== Cochlea ===<br />
<br />
==== Slide 286, Ear Cochlea ====<br />
<br />
The cochlea houses an elaborate configuration of membranous labyrinth and hair cells, called the organ of Corti, designed for auditory reception. The basic shape of the cochlea is that of a snail-shell, or tapering helix. The spiraling tunnel that forms the cochlea of the bony labyrinth is divided into three distinct channels by portions of the membranous labyrinth attached to bony ridges. The central column of the helical cochlea contains axons serving the organ of Corti on their way to the auditory nerve. <br />
<br />
<peir-vm>UAB-Histology-00286</peir-vm><br />
<br />
=== Organ of Corti ===<br />
<br />
The organ of Corti is an elaborate structure with more named parts than the rest of inner ear. The organ of Corti is a long strip of tissue that extends the length of the scala media, from the base of the cochlea to its apex. Within the complex strip of tissue that comprises the organ of Corti are specialized sensory hair cells. The whole organ of Corti rests on the basilar membrane which supports the basal ends of the hair cells in the organ of Corti. The apical ends of hair cells touch the tectorial membrane, a "shelf" of jelly that is supported immovably on the spiral lamina. When the basilar membrane flexes in respond to sound waves (i.e., pressure waves delivered to inner-ear fluid by the middle-ear ossicles), the organ of Corti, including its hair cells, also moves. Thus, when the basilar membrane is moved by pressure waves (i.e., sound), the hair cells move relative to the tectorial membrane, causing stimulatory deflection of the apical ends of the hair cells.<br />
<br />
=== Endolymph and Perilymph ===<br />
<br />
The membranous labyrinth is filled with endolymph and is surrounded by perilymph. Endolymph is a unique fluid, with high K+ concentration and very low Na+ concentration. This endolymph provides the proper ionic environment for hair cell function. Endolymph is secreted by cells of the stria vascularis, along the scala media of the cochlea. <br />
<br />
In the vestibular system (surrounding the saccule, utricle, and semicircular canals), perilymph simply provides a cushioning support for the membranous labyrinth.<br />
<br />
In the cochlea, perilymph of the ascending scala vestibuli and the descending scala tympani conveys pressure waves (sound) across the scala media. Pressure waves flex the basilar membrane and thereby stimulate hair cells of the organ of Corti.<br />
<br />
<br />
{{Template:Histologic}}<br />
<br />
[[Category:Histologic]]</div>Matthew Andersonhttps://peir.path.uab.edu/index.php?title=File:HistologicChapter19EarDiagram.jpg&diff=3274File:HistologicChapter19EarDiagram.jpg2014-07-21T23:22:23Z<p>Matthew Anderson: </p>
<hr />
<div></div>Matthew Andersonhttps://peir.path.uab.edu/index.php?title=Histologic:Chapter_19&diff=3273Histologic:Chapter 192014-07-21T23:20:23Z<p>Matthew Anderson: /* Retina */</p>
<hr />
<div>== Eye ==<br />
[[File:HistologicChapter19EyeDiagramUveitis.jpg|thumb|200px|Eye Diagram Uveitis]]<br />
=== Slide 285, Eye ===<br />
<br />
The eyeball is composed of three principal layers. <br />
<br />
The outer layer, or sclera, consists of dense fibrous connective tissue. The sclera is the "white" of the eye. The sclera is continuous with the transparent substantia propria of the cornea. The exposed front surface of the eye, including the cornea, is also covered by a thin, non-keratinized stratified squamous epithelium. <br />
<br />
The next layer, or choroid, consists of heavily pigmented loose connective tissue, including many melanocytes. The choroid is normally not visible behind the "white" of the sclera. The choroid is continuous with the iris; together the choroid and iris are called the uvea. A hole in this layer, the pupil, allows light to pass through.<br />
<br />
The inner layer, or retina, includes two portions. The neural retina is the photoreceptive, imaging-processing tissue. And the pigmented epithelium lies behind the neural retina; it also extends forward to line the iris. The lens is a specialized epithelial structure, suspended behind the pupil.<br />
<br />
The anterior chamber, the space between the iris and the cornea, is filled with aqueous humor. And the posterior chamber lies behind the iris.<br />
<br />
<peir-vm>UAB-Histology-00285</peir-vm><br />
<br />
=== Cornea ===<br />
<br />
The cornea consists of a thin surface epithelium (non-keratinized stratified squamous epithelium) overlying a layer of dense fibrous connective tissue, called the substantia propria. The epithelium of the cornea is continuous with the epithelium of the conjunctiva, both that of the eyeball itself and that of the inside of the eyelid; however the corneal epithelium is very thin (only a few cells thick) which leads to its transparency. The basement membrane between the corneal epithelium and the substantia propria is exceptionally thick and is called Bowman's membrane. Collagen of the cornea is organized into extremely regular layers. All the collagen fibers in one layer arranged in parallel, and alternating layers run in different directions. Corneal connective tissue has no blood vessels. Even though cells of the cornea are not very active metabolically, they still need oxygen and nutrients. As long as the cornea is in direct contact with air, oxygen can be absorbed directly and nutrients can diffuse into cornea from the aqueous humor. Cells of cornea are limited to fibroblasts and there are no blood vessels so there are no immune-system components; hence corneal tissue can be transplanted without need for careful tissue typing.<br />
<br />
At the inner surface of the cornea, a thick basal lamina (Decemet's membrane) separates the substantia propria from a layer of simple low cuboidal epithelium, called the corneal endothelium.<br />
<br />
Corneal epithelium contains free nerve endings. Since pain seems to be the only sensory modality that functions for corneal tissue, biologists long ago decided that free nerve endings elsewhere may also represent pain fibers.<br />
<br />
=== Iris ===<br />
<br />
Functionally, the iris is a rather simple opaque ring surrounding and controlling the diameter of its central aperture - the pupil. A ring of smooth muscle surrounding the pupil comprises the pupillary sphincter. The color of the iris ("eye color") results both from scattering of light by its trabecular meshwork of collagen fibers and from absorption of light by melanin granules in scattered melanocytes. Variations in eye color result from individual differences in the distribution and density of melanocytes and trabecular meshwork.<br />
<br />
=== Lens ===<br />
<br />
The lens is an isolated island of epithelial tissue with an anterior layer that is simple cuboidal and a posterior layer consisting of elongated cells, called lens fibers that are packed with lens protein. The shape of the lens (and hence its focal length) is determined by tension exerted through the suspensory fibers, controlled by smooth muscle of the ciliary body.<br />
<br />
=== Ciliary Body and Suspensory Fibers (zonules) ===<br />
<br />
Deep to the limbus (i.e., the site where the cornea meets the sclera), the choroid layer is thickened into the ciliary body. The ciliary body is a ring of smooth muscle fibers arranged concentrically around the opening in which the lens is suspended. The lens is suspended from the ciliary body by thin fibers of collagen, called suspensory fibers or zonules. Together, the ciliary body and suspensory fibers control the shape of the lens. The surface of the ciliary body is covered by an extension of the embryonic optic cup and small projections of this tissue from the ciliary processes, which secretes the aqueous humor. Aqueous humor flows from its site of formation in the posterior chamber (i.e., behind the iris) through the pupil into the anterior chamber. From there it drains into the canal of Schlemm and hence into venous drainage. An imbalance between the formation and drainage of aqueous humor can create increased pressure leading to glaucoma.<br />
<br />
=== Retina ===<br />
[[File:HistologicChapter19Retina.Jpg|thumb|200px|Retina]]<br />
The retina consists of two distinct layers, the neural retina (often called simply "the retina") and the pigmented epithelium.<br />
<br />
The neural retina is the light-sensitive tissue of the eye. The photoreceptor cells (rods and cones) are located in the back of the retina, so light must pass through all of the layers of the neural retina before getting to the receptors. And the blood vessels which serve the retina are spread across the front surface, so light on its way to the receptors must also pass by the blood vessels. The nerve fibers which eventually travel from the eye through the optic nerve must pass through the layers of the retina, leaving a "blind spot" where they do so. <br />
<br />
Cells comprising the neural retina form several layers.<br />
<br />
*The innermost layer is the inner limiting membrane, a basal lamina separating nervous tissue of the retina from connective tissue of the vitreous humor. <br />
*The layer of nerve fibers contains axons from ganglion cells which travel across the retina to the optic nerve and hence past the optic chiasm into the optic tract and into lateral geniculate nucleus of the thalamus.<br />
*The ganglion cell layer contains the cell bodies of ganglion cells, the cells whose axons project to the brain.<br />
*The inner plexiform layer contains dendrites of ganglion cells synapsing with axons of bipolar cells.<br />
*The inner nuclear layer contains the cell bodies of bipolar cells<br />
*The outer plexiform layer contains dendrites of bipolar cells synapsing with axons of photoreceptor cells.<br />
*The outer nuclear layer contains the cell bodies of receptor cells.<br />
*Between the outer nuclear layer and the receptor layer is the site of the outer limiting membrane, a basal lamina bounding the neural retina. <br />
<br />
The outer segments (rods and cones) of the receptor cells penetrate the outer membrane to contact the pigmented epithelium.<br />
<br />
*The receptor layer contains the photoreceptive outer segments (rods and cones) of receptor cells.<br />
<br />
Photoreceptor cells come in two types, rods and cones. Rods are sensitive to dim light and provide night vision. Rods are more numerous in the peripheral retina. Cones need brighter light and provide daytime color vision. Cones are more prevalent in the vicinity of the fovea.<br />
<br />
== Ear ==<br />
<br />
The ear has three distinct regions -- outer ear, middle ear, and inner ear.<br />
<br />
The outer ear includes the pinna (the visible ear, consisting mostly of skin and cartilage) and the ear canal. The latter is lined by keratinized stratified squamous epithelium. This lining differs from skin by the presence of specialized ceruminous (ear-wax) glands.<br />
<br />
The middle ear is basically a space, communicating via the eustacian tube with the oropharynx. It is lined by a very thin non-keratinized stratified squamous epithelium. Spanning the space of the middle ear are the three middle ear bones, the malleus (hammer), incus (anvil), and stapes (stirrup).<br />
<br />
The eardrum is a thin membrane separating the outer ear from the middle ear. It is sandwich of tissues, with keratinized stratified squamous epithelium facing the outer ear, non-keratinized stratified squamous epithelium facing the middle ear, and a very thin layer of connective tissue in between.<br />
<br />
The inner ear is the portion of the ear which contains sensory receptors. <br />
<br />
=== Inner Ear ===<br />
<br />
The inner ear consists of fluid-filled sacs (membranous labyrinth) that lie in cavities in the temporal bone of the skull (bony or osseous labyrinth). The inner ear contains sense organs serving both balance and hearing. Head position (i.e., gravity; also linear acceleration) is sensed by the otolith organs of the saccule and utricle. Head rotation (i.e., angular acceleration) is sensed by the cristae ampularis of the semicircular canals. And hearing is sensed by the organ of Corti within the scala media of the cochlea. All of these senses of the inner ear utilize the same mechanoreceptor cell type: epithelial hair cells. <br />
<br />
Hair cells, the specialized mechanoreceptor cells of the auditory and vestibular systems, are found in several positions along the chambers and passageways of the membranous labyrinth. Hair cells are basically columnar epithelial cells. At the apical end of each hair cell is a set of "hairs" (cytoplasmic projections, kinocilium and stereocilia) embedded in a mass of extracellular jelly. At the basal end of each hair cell are synapses onto sensory axons. A hair cell responds when movement of the extracellular jelly displaces its kinocilium and stereocilia. Displacement of the kinocilium and stereocilia alters conductance of ion channels, in turn affecting release of neurotransmitter onto the associated sensory axon. (These axons project along the auditory and vestibular nerves, cranial nerve VIII).<br />
<br />
=== Semicircular Canals ===<br />
<br />
Each semicircular canal of the bony labyrinth is a hollow passageway looping out from and back to the vestibule. Within each of these passageways is a semicircular canal of the membranous labyrinth. At one end of each membranous semicircular canal is a small enlargement called the ampulla. Within each ampulla is a ridge or "crest" called the crista that is covered with hair cells. A small mass of jelly, called the cupola ("cap") rests on top of the hair cells of the crista. The hair cells of the ampullae respond to angular acceleration (i.e., rotation of the head) <br />
<br />
There are three semicircular canals in each ear, oriented in three mutually-perpendicular planes. Rotation of the head in any direction will cause inertial fluid movement in one or more of the semicircular canals. <br />
<br />
=== Cochlea ===<br />
<br />
==== Slide 286, Ear Cochlea ====<br />
<br />
The cochlea houses an elaborate configuration of membranous labyrinth and hair cells, called the organ of Corti, designed for auditory reception. The basic shape of the cochlea is that of a snail-shell, or tapering helix. The spiraling tunnel that forms the cochlea of the bony labyrinth is divided into three distinct channels by portions of the membranous labyrinth attached to bony ridges. The central column of the helical cochlea contains axons serving the organ of Corti on their way to the auditory nerve. <br />
<br />
<peir-vm>UAB-Histology-00286</peir-vm><br />
<br />
=== Organ of Corti ===<br />
<br />
The organ of Corti is an elaborate structure with more named parts than the rest of inner ear. The organ of Corti is a long strip of tissue that extends the length of the scala media, from the base of the cochlea to its apex. Within the complex strip of tissue that comprises the organ of Corti are specialized sensory hair cells. The whole organ of Corti rests on the basilar membrane which supports the basal ends of the hair cells in the organ of Corti. The apical ends of hair cells touch the tectorial membrane, a "shelf" of jelly that is supported immovably on the spiral lamina. When the basilar membrane flexes in respond to sound waves (i.e., pressure waves delivered to inner-ear fluid by the middle-ear ossicles), the organ of Corti, including its hair cells, also moves. Thus, when the basilar membrane is moved by pressure waves (i.e., sound), the hair cells move relative to the tectorial membrane, causing stimulatory deflection of the apical ends of the hair cells.<br />
<br />
=== Endolymph and Perilymph ===<br />
<br />
The membranous labyrinth is filled with endolymph and is surrounded by perilymph. Endolymph is a unique fluid, with high K+ concentration and very low Na+ concentration. This endolymph provides the proper ionic environment for hair cell function. Endolymph is secreted by cells of the stria vascularis, along the scala media of the cochlea. <br />
<br />
In the vestibular system (surrounding the saccule, utricle, and semicircular canals), perilymph simply provides a cushioning support for the membranous labyrinth.<br />
<br />
In the cochlea, perilymph of the ascending scala vestibuli and the descending scala tympani conveys pressure waves (sound) across the scala media. Pressure waves flex the basilar membrane and thereby stimulate hair cells of the organ of Corti.<br />
<br />
<br />
{{Template:Histologic}}<br />
<br />
[[Category:Histologic]]</div>Matthew Andersonhttps://peir.path.uab.edu/index.php?title=File:HistologicChapter19Retina.Jpg&diff=3272File:HistologicChapter19Retina.Jpg2014-07-21T23:20:03Z<p>Matthew Anderson: </p>
<hr />
<div></div>Matthew Andersonhttps://peir.path.uab.edu/index.php?title=Histologic:Chapter_19&diff=3271Histologic:Chapter 192014-07-21T23:18:37Z<p>Matthew Anderson: /* Eye */</p>
<hr />
<div>== Eye ==<br />
[[File:HistologicChapter19EyeDiagramUveitis.jpg|thumb|200px|Eye Diagram Uveitis]]<br />
=== Slide 285, Eye ===<br />
<br />
The eyeball is composed of three principal layers. <br />
<br />
The outer layer, or sclera, consists of dense fibrous connective tissue. The sclera is the "white" of the eye. The sclera is continuous with the transparent substantia propria of the cornea. The exposed front surface of the eye, including the cornea, is also covered by a thin, non-keratinized stratified squamous epithelium. <br />
<br />
The next layer, or choroid, consists of heavily pigmented loose connective tissue, including many melanocytes. The choroid is normally not visible behind the "white" of the sclera. The choroid is continuous with the iris; together the choroid and iris are called the uvea. A hole in this layer, the pupil, allows light to pass through.<br />
<br />
The inner layer, or retina, includes two portions. The neural retina is the photoreceptive, imaging-processing tissue. And the pigmented epithelium lies behind the neural retina; it also extends forward to line the iris. The lens is a specialized epithelial structure, suspended behind the pupil.<br />
<br />
The anterior chamber, the space between the iris and the cornea, is filled with aqueous humor. And the posterior chamber lies behind the iris.<br />
<br />
<peir-vm>UAB-Histology-00285</peir-vm><br />
<br />
=== Cornea ===<br />
<br />
The cornea consists of a thin surface epithelium (non-keratinized stratified squamous epithelium) overlying a layer of dense fibrous connective tissue, called the substantia propria. The epithelium of the cornea is continuous with the epithelium of the conjunctiva, both that of the eyeball itself and that of the inside of the eyelid; however the corneal epithelium is very thin (only a few cells thick) which leads to its transparency. The basement membrane between the corneal epithelium and the substantia propria is exceptionally thick and is called Bowman's membrane. Collagen of the cornea is organized into extremely regular layers. All the collagen fibers in one layer arranged in parallel, and alternating layers run in different directions. Corneal connective tissue has no blood vessels. Even though cells of the cornea are not very active metabolically, they still need oxygen and nutrients. As long as the cornea is in direct contact with air, oxygen can be absorbed directly and nutrients can diffuse into cornea from the aqueous humor. Cells of cornea are limited to fibroblasts and there are no blood vessels so there are no immune-system components; hence corneal tissue can be transplanted without need for careful tissue typing.<br />
<br />
At the inner surface of the cornea, a thick basal lamina (Decemet's membrane) separates the substantia propria from a layer of simple low cuboidal epithelium, called the corneal endothelium.<br />
<br />
Corneal epithelium contains free nerve endings. Since pain seems to be the only sensory modality that functions for corneal tissue, biologists long ago decided that free nerve endings elsewhere may also represent pain fibers.<br />
<br />
=== Iris ===<br />
<br />
Functionally, the iris is a rather simple opaque ring surrounding and controlling the diameter of its central aperture - the pupil. A ring of smooth muscle surrounding the pupil comprises the pupillary sphincter. The color of the iris ("eye color") results both from scattering of light by its trabecular meshwork of collagen fibers and from absorption of light by melanin granules in scattered melanocytes. Variations in eye color result from individual differences in the distribution and density of melanocytes and trabecular meshwork.<br />
<br />
=== Lens ===<br />
<br />
The lens is an isolated island of epithelial tissue with an anterior layer that is simple cuboidal and a posterior layer consisting of elongated cells, called lens fibers that are packed with lens protein. The shape of the lens (and hence its focal length) is determined by tension exerted through the suspensory fibers, controlled by smooth muscle of the ciliary body.<br />
<br />
=== Ciliary Body and Suspensory Fibers (zonules) ===<br />
<br />
Deep to the limbus (i.e., the site where the cornea meets the sclera), the choroid layer is thickened into the ciliary body. The ciliary body is a ring of smooth muscle fibers arranged concentrically around the opening in which the lens is suspended. The lens is suspended from the ciliary body by thin fibers of collagen, called suspensory fibers or zonules. Together, the ciliary body and suspensory fibers control the shape of the lens. The surface of the ciliary body is covered by an extension of the embryonic optic cup and small projections of this tissue from the ciliary processes, which secretes the aqueous humor. Aqueous humor flows from its site of formation in the posterior chamber (i.e., behind the iris) through the pupil into the anterior chamber. From there it drains into the canal of Schlemm and hence into venous drainage. An imbalance between the formation and drainage of aqueous humor can create increased pressure leading to glaucoma.<br />
<br />
=== Retina ===<br />
<br />
The retina consists of two distinct layers, the neural retina (often called simply "the retina") and the pigmented epithelium.<br />
<br />
The neural retina is the light-sensitive tissue of the eye. The photoreceptor cells (rods and cones) are located in the back of the retina, so light must pass through all of the layers of the neural retina before getting to the receptors. And the blood vessels which serve the retina are spread across the front surface, so light on its way to the receptors must also pass by the blood vessels. The nerve fibers which eventually travel from the eye through the optic nerve must pass through the layers of the retina, leaving a "blind spot" where they do so. <br />
<br />
Cells comprising the neural retina form several layers.<br />
<br />
*The innermost layer is the inner limiting membrane, a basal lamina separating nervous tissue of the retina from connective tissue of the vitreous humor. <br />
*The layer of nerve fibers contains axons from ganglion cells which travel across the retina to the optic nerve and hence past the optic chiasm into the optic tract and into lateral geniculate nucleus of the thalamus.<br />
*The ganglion cell layer contains the cell bodies of ganglion cells, the cells whose axons project to the brain.<br />
*The inner plexiform layer contains dendrites of ganglion cells synapsing with axons of bipolar cells.<br />
*The inner nuclear layer contains the cell bodies of bipolar cells<br />
*The outer plexiform layer contains dendrites of bipolar cells synapsing with axons of photoreceptor cells.<br />
*The outer nuclear layer contains the cell bodies of receptor cells.<br />
*Between the outer nuclear layer and the receptor layer is the site of the outer limiting membrane, a basal lamina bounding the neural retina. <br />
<br />
The outer segments (rods and cones) of the receptor cells penetrate the outer membrane to contact the pigmented epithelium.<br />
<br />
*The receptor layer contains the photoreceptive outer segments (rods and cones) of receptor cells.<br />
<br />
Photoreceptor cells come in two types, rods and cones. Rods are sensitive to dim light and provide night vision. Rods are more numerous in the peripheral retina. Cones need brighter light and provide daytime color vision. Cones are more prevalent in the vicinity of the fovea.<br />
<br />
== Ear ==<br />
<br />
The ear has three distinct regions -- outer ear, middle ear, and inner ear.<br />
<br />
The outer ear includes the pinna (the visible ear, consisting mostly of skin and cartilage) and the ear canal. The latter is lined by keratinized stratified squamous epithelium. This lining differs from skin by the presence of specialized ceruminous (ear-wax) glands.<br />
<br />
The middle ear is basically a space, communicating via the eustacian tube with the oropharynx. It is lined by a very thin non-keratinized stratified squamous epithelium. Spanning the space of the middle ear are the three middle ear bones, the malleus (hammer), incus (anvil), and stapes (stirrup).<br />
<br />
The eardrum is a thin membrane separating the outer ear from the middle ear. It is sandwich of tissues, with keratinized stratified squamous epithelium facing the outer ear, non-keratinized stratified squamous epithelium facing the middle ear, and a very thin layer of connective tissue in between.<br />
<br />
The inner ear is the portion of the ear which contains sensory receptors. <br />
<br />
=== Inner Ear ===<br />
<br />
The inner ear consists of fluid-filled sacs (membranous labyrinth) that lie in cavities in the temporal bone of the skull (bony or osseous labyrinth). The inner ear contains sense organs serving both balance and hearing. Head position (i.e., gravity; also linear acceleration) is sensed by the otolith organs of the saccule and utricle. Head rotation (i.e., angular acceleration) is sensed by the cristae ampularis of the semicircular canals. And hearing is sensed by the organ of Corti within the scala media of the cochlea. All of these senses of the inner ear utilize the same mechanoreceptor cell type: epithelial hair cells. <br />
<br />
Hair cells, the specialized mechanoreceptor cells of the auditory and vestibular systems, are found in several positions along the chambers and passageways of the membranous labyrinth. Hair cells are basically columnar epithelial cells. At the apical end of each hair cell is a set of "hairs" (cytoplasmic projections, kinocilium and stereocilia) embedded in a mass of extracellular jelly. At the basal end of each hair cell are synapses onto sensory axons. A hair cell responds when movement of the extracellular jelly displaces its kinocilium and stereocilia. Displacement of the kinocilium and stereocilia alters conductance of ion channels, in turn affecting release of neurotransmitter onto the associated sensory axon. (These axons project along the auditory and vestibular nerves, cranial nerve VIII).<br />
<br />
=== Semicircular Canals ===<br />
<br />
Each semicircular canal of the bony labyrinth is a hollow passageway looping out from and back to the vestibule. Within each of these passageways is a semicircular canal of the membranous labyrinth. At one end of each membranous semicircular canal is a small enlargement called the ampulla. Within each ampulla is a ridge or "crest" called the crista that is covered with hair cells. A small mass of jelly, called the cupola ("cap") rests on top of the hair cells of the crista. The hair cells of the ampullae respond to angular acceleration (i.e., rotation of the head) <br />
<br />
There are three semicircular canals in each ear, oriented in three mutually-perpendicular planes. Rotation of the head in any direction will cause inertial fluid movement in one or more of the semicircular canals. <br />
<br />
=== Cochlea ===<br />
<br />
==== Slide 286, Ear Cochlea ====<br />
<br />
The cochlea houses an elaborate configuration of membranous labyrinth and hair cells, called the organ of Corti, designed for auditory reception. The basic shape of the cochlea is that of a snail-shell, or tapering helix. The spiraling tunnel that forms the cochlea of the bony labyrinth is divided into three distinct channels by portions of the membranous labyrinth attached to bony ridges. The central column of the helical cochlea contains axons serving the organ of Corti on their way to the auditory nerve. <br />
<br />
<peir-vm>UAB-Histology-00286</peir-vm><br />
<br />
=== Organ of Corti ===<br />
<br />
The organ of Corti is an elaborate structure with more named parts than the rest of inner ear. The organ of Corti is a long strip of tissue that extends the length of the scala media, from the base of the cochlea to its apex. Within the complex strip of tissue that comprises the organ of Corti are specialized sensory hair cells. The whole organ of Corti rests on the basilar membrane which supports the basal ends of the hair cells in the organ of Corti. The apical ends of hair cells touch the tectorial membrane, a "shelf" of jelly that is supported immovably on the spiral lamina. When the basilar membrane flexes in respond to sound waves (i.e., pressure waves delivered to inner-ear fluid by the middle-ear ossicles), the organ of Corti, including its hair cells, also moves. Thus, when the basilar membrane is moved by pressure waves (i.e., sound), the hair cells move relative to the tectorial membrane, causing stimulatory deflection of the apical ends of the hair cells.<br />
<br />
=== Endolymph and Perilymph ===<br />
<br />
The membranous labyrinth is filled with endolymph and is surrounded by perilymph. Endolymph is a unique fluid, with high K+ concentration and very low Na+ concentration. This endolymph provides the proper ionic environment for hair cell function. Endolymph is secreted by cells of the stria vascularis, along the scala media of the cochlea. <br />
<br />
In the vestibular system (surrounding the saccule, utricle, and semicircular canals), perilymph simply provides a cushioning support for the membranous labyrinth.<br />
<br />
In the cochlea, perilymph of the ascending scala vestibuli and the descending scala tympani conveys pressure waves (sound) across the scala media. Pressure waves flex the basilar membrane and thereby stimulate hair cells of the organ of Corti.<br />
<br />
<br />
{{Template:Histologic}}<br />
<br />
[[Category:Histologic]]</div>Matthew Andersonhttps://peir.path.uab.edu/index.php?title=File:HistologicChapter19EyeDiagramUveitis.jpg&diff=3270File:HistologicChapter19EyeDiagramUveitis.jpg2014-07-21T23:18:12Z<p>Matthew Anderson: </p>
<hr />
<div></div>Matthew Andersonhttps://peir.path.uab.edu/index.php?title=Template:Histologic&diff=3269Template:Histologic2014-07-21T23:16:28Z<p>Matthew Anderson: </p>
<hr />
<div>{{Navbox<br />
|name = Histologic<br />
|title = [[Histologic]]<br />
|bodyclass = hlist<br />
[[Histologic]]<br />
|group1 = [[Histologic:Chapter 1|Chapter 1]]<br />
|list1 =<br />
* [[Histologic:Chapter 1#Introduction|Introduction]]<br />
* [[Histologic:Chapter 1#Overview_of_Tissue_Preparation_and_Staining_for_Microscopy|Overview of Tissue Preparation and Staining for Microscopy]]<br />
* [[Histologic:Chapter 1#Using_Histologic|Using Histologic]]<br />
|group2 = [[Histologic:Chapter 2|Chapter 2]]<br />
|list2 =<br />
* [[Histologic:Chapter 2#Cells,_Organelles,_and_Inclusions|Cells, Organelles, and Inclusions]]<br />
* [[Histologic:Chapter 2#Mitosis|Mitosis]]<br />
|group3 = [[Histologic:Chapter 3|Chapter 3]]<br />
|list3 =<br />
* [[Histologic:Chapter 3#Introduction|Introduction]]<br />
* [[Histologic:Chapter 3#Simple_Epithelium|Simple Epithelium]]<br />
* [[Histologic:Chapter 3#Stratified_Epithelium|Stratified Epithelium]]<br />
|group4 = [[Histologic:Chapter 4|Chapter 4]]<br />
|list4 =<br />
* [[Histologic:Chapter 4#Introduction|Introduction]]<br />
* [[Histologic:Chapter 4#Loose_Connective_Tissue|Loose Connective Tissue]]<br />
* [[Histologic:Chapter 4#Dense_Connective_Tissue|Dense Connective Tissue]]<br />
* [[Histologic:Chapter 4#Adipose_Tissue|Adipose Tissue]]<br />
|group5 = [[Histologic:Chapter 5|Chapter 5]]<br />
|list5 =<br />
* [[Histologic:Chapter 5#Introduction|Introduction]]<br />
* [[Histologic:Chapter 5#Smooth_Muscle|Smooth Muscle]]<br />
* [[Histologic:Chapter 5#Skeletal_Muscle|Skeletal Muscle]]<br />
* [[Histologic:Chapter 5#Cardiac_Muscle|Cardiac Muscle]]<br />
|group6 = [[Histologic:Chapter 6|Chapter 6]]<br />
|list6 =<br />
* [[Histologic:Chapter 6#Introduction|Introduction]]<br />
* [[Histologic:Chapter 6#Nerve_Fibers_And_Nerves|Nerve Fibers And Nerves]]<br />
* [[Histologic:Chapter 6#Central_Nervous_System:_Brain|Central Nervous System: Brain]]<br />
* [[Histologic:Chapter 6#Spinal_Cord_-_General_Structure|Spinal Cord - General Structure]]<br />
* [[Histologic:Chapter 6#Sympathetic_Chain_Ganglion_With_Multipolar_Neurons|Sympathetic Chain Ganglion With Multipolar Neurons]]<br />
* [[Histologic:Chapter 6#Parasympathetic_Ganglia|Parasympathetic Ganglia]]<br />
|group7 = [[Histologic:Chapter 7|Chapter 7]]<br />
|list7 =<br />
* [[Histologic:Chapter 7#Introduction|Introduction]]<br />
* [[Histologic:Chapter 7#Blood_Smears|Blood Smears]]<br />
|group8 = [[Histologic:Chapter 8|Chapter 8]]<br />
|list8 =<br />
* [[Histologic:Chapter 8#Introduction|Introduction]]<br />
* [[Histologic:Chapter 8#Lymph_Nodes|Lymph Nodes]]<br />
* [[Histologic:Chapter 8#Thymus|Thymus]]<br />
* [[Histologic:Chapter 8#Tonsils|Tonsils]]<br />
* [[Histologic:Chapter 8#Spleen|Spleen]]<br />
|group9 = [[Histologic:Chapter 9|Chapter 9]]<br />
|list9 =<br />
* [[Histologic:Chapter 9#Introduction|Introduction]]<br />
* [[Histologic:Chapter 9#Small_Blood_Vessels|Small Blood Vessels]]<br />
* [[Histologic:Chapter 9#Medium-Sized_Blood_Vessels|Medium-Sized Blood Vessels]]<br />
* [[Histologic:Chapter 9#Large_Arteries|Large Arteries]]<br />
* [[Histologic:Chapter 9#Large_Veins|Large Veins]]<br />
|group10 = [[Histologic:Chapter 10|Chapter 10]]<br />
|list10 =<br />
* [[Histologic:Chapter 10#Olfactory_Area|Olfactory Area]]<br />
* [[Histologic:Chapter 10#Epiglottis|Epiglottis]]<br />
* [[Histologic:Chapter 10#Trachea|Trachea]]<br />
* [[Histologic:Chapter 10#Bronchi,_Bronchioles,_and_Lung|Bronchi, Bronchioles, and Lung]]<br />
|group11 = [[Histologic:Chapter 11|Chapter 11]]<br />
|list11 =<br />
* [[Histologic:Chapter 11#Lip|Lip]]<br />
* [[Histologic:Chapter 11#Tongue|Tongue]]<br />
* [[Histologic:Chapter 11#Salivary_Glands|Salivary Glands]]<br />
* [[Histologic:Chapter 11#Pancreas|Pancreas]]<br />
* [[Histologic:Chapter 11#Esophagus|Esophagus]]<br />
* [[Histologic:Chapter 11#Stomach|Stomach]]<br />
* [[Histologic:Chapter 11#Small_Intestine|Small Intestine]]<br />
* [[Histologic:Chapter 11#Pylorus-Duodenal_Junction|Pylorus-Duodenal Junction]]<br />
* [[Histologic:Chapter 11#Duodenum|Duodenum]]<br />
* [[Histologic:Chapter 11#Jejunum|Jejunum]]<br />
* [[Histologic:Chapter 11#Ileum|Ileum]]<br />
* [[Histologic:Chapter 11#Appendix|Appendix]]<br />
* [[Histologic:Chapter 11#Colon|Colon]]<br />
* [[Histologic:Chapter 11#Rectum|Rectum]]<br />
* [[Histologic:Chapter 11#Anal_Canal|Anal Canal]]<br />
|group12 = [[Histologic:Chapter 12|Chapter 12]]<br />
|list12 =<br />
* [[Histologic:Chapter 12#Introduction|Introduction]]<br />
* [[Histologic:Chapter 12#Gallbladder|Gallbladder]]<br />
|group13 = [[Histologic:Chapter 13|Chapter 13]]<br />
|list13 =<br />
* [[Histologic:Chapter 13#Skeletal_Muscle|Skeletal Muscle]]<br />
* [[Histologic:Chapter 13#Cartilage|Cartilage]]<br />
* [[Histologic:Chapter 13#Bone|Bone]]<br />
* [[Histologic:Chapter 13#Joints|Joints]]<br />
|group14 = [[Histologic:Chapter 14|Chapter 14]]<br />
|list14 =<br />
* [[Histologic:Chapter 14#Introduction|Introduction]]<br />
* [[Histologic:Chapter 14#Pituitary_Gland_(Hypophysis)|Pituitary Gland (Hypophysis)]]<br />
* [[Histologic:Chapter 14#Thyroid|Thyroid]]<br />
* [[Histologic:Chapter 14#Parathyroid|Parathyroid]]<br />
* [[Histologic:Chapter 14#Suprarenal_(Adrenal)_Glands|Suprarenal (Adrenal) Glands]]<br />
* [[Histologic:Chapter 14#Endocrine_Pancreas_(Pancreatic_Islets_of_Langerhans)|Endocrine Pancreas (Pancreatic Islets of Langerhans)]]<br />
|group15 = [[Histologic:Chapter 15|Chapter 15]]<br />
|list15 =<br />
* [[Histologic:Chapter 15#Kidney|Kidney]]<br />
* [[Histologic:Chapter 15#Ureter_and_Urinary_Bladder|Ureter And Urinary Bladder]]<br />
|group16 = [[Histologic:Chapter 16|Chapter 16]]<br />
|list16 =<br />
* [[Histologic:Chapter 16#Introduction|Introduction]]<br />
* [[Histologic:Chapter 16#The_Testis|The Testis]]<br />
* [[Histologic:Chapter 16#Genital_Ducts|Genital Ducts]]<br />
* [[Histologic:Chapter 16#Accessory_Glands|Accessory Glands]]<br />
* [[Histologic:Chapter 16#Penis|Penis]]<br />
|group17 = [[Histologic:Chapter 17|Chapter 17]]<br />
|list17 =<br />
* [[Histologic:Chapter 17#Introduction|Introduction]]<br />
* [[Histologic:Chapter 17#Ovary|Ovary]]<br />
* [[Histologic:Chapter 17#Uterine_Tube|Uterine Tube]]<br />
* [[Histologic:Chapter 17#Uterus|Uterus]]<br />
* [[Histologic:Chapter 17#Vagina|Vagina]]<br />
* [[Histologic:Chapter 17#Placenta_and_Umbilical_Cord|Placenta and Umbilical Cord]]<br />
* [[Histologic:Chapter 17#Umbilical_Cord|Umbilical Cord]]<br />
|group18 = [[Histologic:Chapter 18|Chapter 18]]<br />
|list18 =<br />
* [[Histologic:Chapter 18#Introduction|Introduction]]<br />
* [[Histologic:Chapter 18#Mammary_Gland|Mammary Gland]]<br />
* [[Histologic:Chapter 18#Nipple_Microanatomy|Nipple Microanatomy]]<br />
|group19 = [[Histologic:Chapter 19|Chapter 19]]<br />
|list19 =<br />
* [[Histologic:Chapter 19#Eye|Eye]]<br />
* [[Histologic:Chapter 19#Ear|Ear]]<br />
|group20 = [[Histologic:Contributors|Contributors]]<br />
|list20 =<br />
* [[Histologic:Contributors#Acknowledgements|Acknowledgements]]<br />
* [[Histologic:Contributors#Staff|Staff]]<br />
<br />
}}<noinclude><br />
<br />
[[Category:Histologic Templates]]<br />
[[Category:Histologic]]<br />
</noinclude></div>Matthew Andersonhttps://peir.path.uab.edu/index.php?title=Histologic&diff=3268Histologic2014-07-21T23:15:49Z<p>Matthew Anderson: </p>
<hr />
<div>Welcome to [[Histologic]], a constantly-updated, wiki-based comprehensive manual for the teaching of histology at the [http://www.uab.edu/medicine/home/ University of Alabama at Birmingham School of Medicine]. It integrates still images from the [{{SERVER}}/library PEIR Digital Library] and whole slide images from the [http://peir-vm.path.uab.edu PEIR-VM] project. For usage instructions, please see [[Histologic:Chapter 1|Chapter 1]]. To get in touch with us, please see [[Histologic:Contributors|Contributors]].<br />
<br />
== [[Histologic:Chapter 1|Chapter 1: Overview]] ==<br />
* [[Histologic:Chapter 1#Introduction|Introduction]]<br />
* [[Histologic:Chapter 1#Overview_of_Tissue_Preparation_and_Staining_for_Microscopy|Overview of Tissue Preparation and Staining for Microscopy]]<br />
* [[Histologic:Chapter 1#Using_Histologic|Using Histologic]]<br />
<br />
== [[Histologic:Chapter 2|Chapter 2: The Cell]] ==<br />
* [[Histologic:Chapter 2#Cells,_Organelles,_and_Inclusions|Cells, Organelles, and Inclusions]]<br />
* [[Histologic:Chapter 2#Mitosis|Mitosis]]<br />
<br />
== [[Histologic:Chapter 3|Chapter 3: Epithelial Cells]] ==<br />
* [[Histologic:Chapter 3#Introduction|Introduction]]<br />
* [[Histologic:Chapter 3#Simple_Epithelium|Simple Epithelium]]<br />
* [[Histologic:Chapter 3#Stratified_Epithelium|Stratified Epithelium]]<br />
<br />
== [[Histologic:Chapter 4|Chapter 4: Support Cells and the Extracellular Matrix]] ==<br />
* [[Histologic:Chapter 4#Introduction|Introduction]]<br />
* [[Histologic:Chapter 4#Loose_Connective_Tissue|Loose Connective Tissue]]<br />
* [[Histologic:Chapter 4#Dense_Connective_Tissue|Dense Connective Tissue]]<br />
* [[Histologic:Chapter 4#Adipose_Tissue|Adipose Tissue]]<br />
<br />
== [[Histologic:Chapter 5|Chapter 5: Contractile Cells]] ==<br />
* [[Histologic:Chapter 5#Introduction|Introduction]]<br />
* [[Histologic:Chapter 5#Smooth_Muscle|Smooth Muscle]]<br />
* [[Histologic:Chapter 5#Skeletal_Muscle|Skeletal Muscle]]<br />
* [[Histologic:Chapter 5#Cardiac_Muscle|Cardiac Muscle]]<br />
<br />
== [[Histologic:Chapter 6|Chapter 6: Nervous Tissue]] ==<br />
* [[Histologic:Chapter 6#Introduction|Introduction]]<br />
* [[Histologic:Chapter 6#Nerve_Fibers_And_Nerves|Nerve Fibers And Nerves]]<br />
* [[Histologic:Chapter 6#Central_Nervous_System:_Brain|Central Nervous System: Brain]]<br />
* [[Histologic:Chapter 6#Spinal_Cord_-_General_Structure|Spinal Cord - General Structure]]<br />
* [[Histologic:Chapter 6#Sympathetic_Chain_Ganglion_With_Multipolar_Neurons|Sympathetic Chain Ganglion With Multipolar Neurons]]<br />
* [[Histologic:Chapter 6#Parasympathetic_Ganglia|Parasympathetic Ganglia]]<br />
<br />
== [[Histologic:Chapter 7|Chapter 7: Blood Cells]] ==<br />
* [[Histologic:Chapter 7#Introduction|Introduction]]<br />
* [[Histologic:Chapter 7#Blood_Smears|Blood Smears]]<br />
<br />
== [[Histologic:Chapter 8|Chapter 8: Immune System]] ==<br />
* [[Histologic:Chapter 8#Introduction|Introduction]]<br />
* [[Histologic:Chapter 8#Lymph_Nodes|Lymph Nodes]]<br />
* [[Histologic:Chapter 8#Thymus|Thymus]]<br />
* [[Histologic:Chapter 8#Tonsils|Tonsils]]<br />
* [[Histologic:Chapter 8#Spleen|Spleen]]<br />
<br />
== [[Histologic:Chapter 9|Chapter 9: Blood and Lymphatic Circulatory Systems and Heart]] ==<br />
* [[Histologic:Chapter 9#Introduction|Introduction]]<br />
* [[Histologic:Chapter 9#Small_Blood_Vessels|Small Blood Vessels]]<br />
* [[Histologic:Chapter 9#Medium-Sized_Blood_Vessels|Medium-Sized Blood Vessels]]<br />
* [[Histologic:Chapter 9#Large_Arteries|Large Arteries]]<br />
* [[Histologic:Chapter 9#Large_Veins|Large Veins]]<br />
<br />
== [[Histologic:Chapter 10|Chapter 10: Respiratory System]] ==<br />
* [[Histologic:Chapter 10#Olfactory_Area|Olfactory Area]]<br />
* [[Histologic:Chapter 10#Epiglottis|Epiglottis]]<br />
* [[Histologic:Chapter 10#Trachea|Trachea]]<br />
* [[Histologic:Chapter 10#Bronchi,_Bronchioles,_and_Lung|Bronchi, Bronchioles, and Lung]]<br />
<br />
== [[Histologic:Chapter 11|Chapter 11: Alimentary Tract]] ==<br />
* [[Histologic:Chapter 11#Lip|Lip]]<br />
* [[Histologic:Chapter 11#Tongue|Tongue]]<br />
* [[Histologic:Chapter 11#Salivary_Glands|Salivary Glands]]<br />
* [[Histologic:Chapter 11#Pancreas|Pancreas]]<br />
* [[Histologic:Chapter 11#Esophagus|Esophagus]]<br />
* [[Histologic:Chapter 11#Stomach|Stomach]]<br />
* [[Histologic:Chapter 11#Small_Intestine|Small Intestine]]<br />
* [[Histologic:Chapter 11#Pylorus-Duodenal_Junction|Pylorus-Duodenal Junction]]<br />
* [[Histologic:Chapter 11#Duodenum|Duodenum]]<br />
* [[Histologic:Chapter 11#Jejunum|Jejunum]]<br />
* [[Histologic:Chapter 11#Ileum|Ileum]]<br />
* [[Histologic:Chapter 11#Appendix|Appendix]]<br />
* [[Histologic:Chapter 11#Colon|Colon]]<br />
* [[Histologic:Chapter 11#Rectum|Rectum]]<br />
* [[Histologic:Chapter 11#Anal_Canal|Anal Canal]]<br />
<br />
== [[Histologic:Chapter 12|Chapter 12: Liver]] ==<br />
* [[Histologic:Chapter 12#Introduction|Introduction]]<br />
* [[Histologic:Chapter 12#Gallbladder|Gallbladder]]<br />
<br />
== [[Histologic:Chapter 13|Chapter 13: Musculoskeletal System]] ==<br />
* [[Histologic:Chapter 13#Skeletal_Muscle|Skeletal Muscle]]<br />
* [[Histologic:Chapter 13#Cartilage|Cartilage]]<br />
* [[Histologic:Chapter 13#Bone|Bone]]<br />
* [[Histologic:Chapter 13#Joints|Joints]]<br />
<br />
== [[Histologic:Chapter 14|Chapter 14: Endocrine System]] ==<br />
* [[Histologic:Chapter 14#Introduction|Introduction]]<br />
* [[Histologic:Chapter 14#Pituitary_Gland_(Hypophysis)|Pituitary Gland (Hypophysis)]]<br />
* [[Histologic:Chapter 14#Thyroid|Thyroid]]<br />
* [[Histologic:Chapter 14#Parathyroid|Parathyroid]]<br />
* [[Histologic:Chapter 14#Suprarenal_(Adrenal)_Glands|Suprarenal (Adrenal) Glands]]<br />
* [[Histologic:Chapter 14#Endocrine_Pancreas_(Pancreatic_Islets_of_Langerhans)|Endocrine Pancreas (Pancreatic Islets of Langerhans)]]<br />
<br />
== [[Histologic:Chapter 15|Chapter 15: Urinary System]] ==<br />
* [[Histologic:Chapter 15#Kidney|Kidney]]<br />
* [[Histologic:Chapter 15#Ureter_and_Urinary_Bladder|Ureter And Urinary Bladder]]<br />
<br />
== [[Histologic:Chapter 16|Chapter 16: Male Reproductive System]] ==<br />
* [[Histologic:Chapter 16#Introduction|Introduction]]<br />
* [[Histologic:Chapter 16#The_Testis|The Testis]]<br />
* [[Histologic:Chapter 16#Genital_Ducts|Genital Ducts]]<br />
* [[Histologic:Chapter 16#Accessory_Glands|Accessory Glands]]<br />
* [[Histologic:Chapter 16#Penis|Penis]]<br />
<br />
== [[Histologic:Chapter 17|Chapter 17: Female Reproductive System]] ==<br />
* [[Histologic:Chapter 17#Introduction|Introduction]]<br />
* [[Histologic:Chapter 17#Ovary|Ovary]]<br />
* [[Histologic:Chapter 17#Uterine_Tube|Uterine Tube]]<br />
* [[Histologic:Chapter 17#Uterus|Uterus]]<br />
* [[Histologic:Chapter 17#Vagina|Vagina]]<br />
* [[Histologic:Chapter 17#Placenta_and_Umbilical_Cord|Placenta and Umbilical Cord]]<br />
* [[Histologic:Chapter 17#Umbilical_Cord|Umbilical Cord]]<br />
<br />
== [[Histologic:Chapter 18|Chapter 18: Skin and Breast]] ==<br />
* [[Histologic:Chapter 18#Introduction|Introduction]]<br />
* [[Histologic:Chapter 18#Mammary_Gland|Mammary Gland]]<br />
* [[Histologic:Chapter 18#Nipple_Microanatomy|Nipple Microanatomy]]<br />
<br />
== [[Histologic:Chapter 19|Chapter 19: Special Senses]] ==<br />
* [[Histologic:Chapter 19#Eye|Eye]]<br />
* [[Histologic:Chapter 19#Ear|Ear]]<br />
<br />
== [[Histologic:Contributors|Contributors]] ==<br />
* [[Histologic:Contributors#Acknowledgements|Acknowledgements]]<br />
* [[Histologic:Contributors#Staff|Staff]]<br />
<br />
[[Category:Histologic]]</div>Matthew Andersonhttps://peir.path.uab.edu/index.php?title=Histologic:Chapter_19&diff=3267Histologic:Chapter 192014-07-21T23:14:30Z<p>Matthew Anderson: Created page with "== Eye == === Slide 285, Eye === The eyeball is composed of three principal layers. The outer layer, or sclera, consists of dense fibrous connective tissue. The sclera i..."</p>
<hr />
<div>== Eye ==<br />
<br />
=== Slide 285, Eye ===<br />
<br />
The eyeball is composed of three principal layers. <br />
<br />
The outer layer, or sclera, consists of dense fibrous connective tissue. The sclera is the "white" of the eye. The sclera is continuous with the transparent substantia propria of the cornea. The exposed front surface of the eye, including the cornea, is also covered by a thin, non-keratinized stratified squamous epithelium. <br />
<br />
The next layer, or choroid, consists of heavily pigmented loose connective tissue, including many melanocytes. The choroid is normally not visible behind the "white" of the sclera. The choroid is continuous with the iris; together the choroid and iris are called the uvea. A hole in this layer, the pupil, allows light to pass through.<br />
<br />
The inner layer, or retina, includes two portions. The neural retina is the photoreceptive, imaging-processing tissue. And the pigmented epithelium lies behind the neural retina; it also extends forward to line the iris. The lens is a specialized epithelial structure, suspended behind the pupil.<br />
<br />
The anterior chamber, the space between the iris and the cornea, is filled with aqueous humor. And the posterior chamber lies behind the iris.<br />
<br />
<peir-vm>UAB-Histology-00285</peir-vm><br />
<br />
=== Cornea ===<br />
<br />
The cornea consists of a thin surface epithelium (non-keratinized stratified squamous epithelium) overlying a layer of dense fibrous connective tissue, called the substantia propria. The epithelium of the cornea is continuous with the epithelium of the conjunctiva, both that of the eyeball itself and that of the inside of the eyelid; however the corneal epithelium is very thin (only a few cells thick) which leads to its transparency. The basement membrane between the corneal epithelium and the substantia propria is exceptionally thick and is called Bowman's membrane. Collagen of the cornea is organized into extremely regular layers. All the collagen fibers in one layer arranged in parallel, and alternating layers run in different directions. Corneal connective tissue has no blood vessels. Even though cells of the cornea are not very active metabolically, they still need oxygen and nutrients. As long as the cornea is in direct contact with air, oxygen can be absorbed directly and nutrients can diffuse into cornea from the aqueous humor. Cells of cornea are limited to fibroblasts and there are no blood vessels so there are no immune-system components; hence corneal tissue can be transplanted without need for careful tissue typing.<br />
<br />
At the inner surface of the cornea, a thick basal lamina (Decemet's membrane) separates the substantia propria from a layer of simple low cuboidal epithelium, called the corneal endothelium.<br />
<br />
Corneal epithelium contains free nerve endings. Since pain seems to be the only sensory modality that functions for corneal tissue, biologists long ago decided that free nerve endings elsewhere may also represent pain fibers.<br />
<br />
=== Iris ===<br />
<br />
Functionally, the iris is a rather simple opaque ring surrounding and controlling the diameter of its central aperture - the pupil. A ring of smooth muscle surrounding the pupil comprises the pupillary sphincter. The color of the iris ("eye color") results both from scattering of light by its trabecular meshwork of collagen fibers and from absorption of light by melanin granules in scattered melanocytes. Variations in eye color result from individual differences in the distribution and density of melanocytes and trabecular meshwork.<br />
<br />
=== Lens ===<br />
<br />
The lens is an isolated island of epithelial tissue with an anterior layer that is simple cuboidal and a posterior layer consisting of elongated cells, called lens fibers that are packed with lens protein. The shape of the lens (and hence its focal length) is determined by tension exerted through the suspensory fibers, controlled by smooth muscle of the ciliary body.<br />
<br />
=== Ciliary Body and Suspensory Fibers (zonules) ===<br />
<br />
Deep to the limbus (i.e., the site where the cornea meets the sclera), the choroid layer is thickened into the ciliary body. The ciliary body is a ring of smooth muscle fibers arranged concentrically around the opening in which the lens is suspended. The lens is suspended from the ciliary body by thin fibers of collagen, called suspensory fibers or zonules. Together, the ciliary body and suspensory fibers control the shape of the lens. The surface of the ciliary body is covered by an extension of the embryonic optic cup and small projections of this tissue from the ciliary processes, which secretes the aqueous humor. Aqueous humor flows from its site of formation in the posterior chamber (i.e., behind the iris) through the pupil into the anterior chamber. From there it drains into the canal of Schlemm and hence into venous drainage. An imbalance between the formation and drainage of aqueous humor can create increased pressure leading to glaucoma.<br />
<br />
=== Retina ===<br />
<br />
The retina consists of two distinct layers, the neural retina (often called simply "the retina") and the pigmented epithelium.<br />
<br />
The neural retina is the light-sensitive tissue of the eye. The photoreceptor cells (rods and cones) are located in the back of the retina, so light must pass through all of the layers of the neural retina before getting to the receptors. And the blood vessels which serve the retina are spread across the front surface, so light on its way to the receptors must also pass by the blood vessels. The nerve fibers which eventually travel from the eye through the optic nerve must pass through the layers of the retina, leaving a "blind spot" where they do so. <br />
<br />
Cells comprising the neural retina form several layers.<br />
<br />
*The innermost layer is the inner limiting membrane, a basal lamina separating nervous tissue of the retina from connective tissue of the vitreous humor. <br />
*The layer of nerve fibers contains axons from ganglion cells which travel across the retina to the optic nerve and hence past the optic chiasm into the optic tract and into lateral geniculate nucleus of the thalamus.<br />
*The ganglion cell layer contains the cell bodies of ganglion cells, the cells whose axons project to the brain.<br />
*The inner plexiform layer contains dendrites of ganglion cells synapsing with axons of bipolar cells.<br />
*The inner nuclear layer contains the cell bodies of bipolar cells<br />
*The outer plexiform layer contains dendrites of bipolar cells synapsing with axons of photoreceptor cells.<br />
*The outer nuclear layer contains the cell bodies of receptor cells.<br />
*Between the outer nuclear layer and the receptor layer is the site of the outer limiting membrane, a basal lamina bounding the neural retina. <br />
<br />
The outer segments (rods and cones) of the receptor cells penetrate the outer membrane to contact the pigmented epithelium.<br />
<br />
*The receptor layer contains the photoreceptive outer segments (rods and cones) of receptor cells.<br />
<br />
Photoreceptor cells come in two types, rods and cones. Rods are sensitive to dim light and provide night vision. Rods are more numerous in the peripheral retina. Cones need brighter light and provide daytime color vision. Cones are more prevalent in the vicinity of the fovea. <br />
<br />
== Ear ==<br />
<br />
The ear has three distinct regions -- outer ear, middle ear, and inner ear.<br />
<br />
The outer ear includes the pinna (the visible ear, consisting mostly of skin and cartilage) and the ear canal. The latter is lined by keratinized stratified squamous epithelium. This lining differs from skin by the presence of specialized ceruminous (ear-wax) glands.<br />
<br />
The middle ear is basically a space, communicating via the eustacian tube with the oropharynx. It is lined by a very thin non-keratinized stratified squamous epithelium. Spanning the space of the middle ear are the three middle ear bones, the malleus (hammer), incus (anvil), and stapes (stirrup).<br />
<br />
The eardrum is a thin membrane separating the outer ear from the middle ear. It is sandwich of tissues, with keratinized stratified squamous epithelium facing the outer ear, non-keratinized stratified squamous epithelium facing the middle ear, and a very thin layer of connective tissue in between.<br />
<br />
The inner ear is the portion of the ear which contains sensory receptors. <br />
<br />
=== Inner Ear ===<br />
<br />
The inner ear consists of fluid-filled sacs (membranous labyrinth) that lie in cavities in the temporal bone of the skull (bony or osseous labyrinth). The inner ear contains sense organs serving both balance and hearing. Head position (i.e., gravity; also linear acceleration) is sensed by the otolith organs of the saccule and utricle. Head rotation (i.e., angular acceleration) is sensed by the cristae ampularis of the semicircular canals. And hearing is sensed by the organ of Corti within the scala media of the cochlea. All of these senses of the inner ear utilize the same mechanoreceptor cell type: epithelial hair cells. <br />
<br />
Hair cells, the specialized mechanoreceptor cells of the auditory and vestibular systems, are found in several positions along the chambers and passageways of the membranous labyrinth. Hair cells are basically columnar epithelial cells. At the apical end of each hair cell is a set of "hairs" (cytoplasmic projections, kinocilium and stereocilia) embedded in a mass of extracellular jelly. At the basal end of each hair cell are synapses onto sensory axons. A hair cell responds when movement of the extracellular jelly displaces its kinocilium and stereocilia. Displacement of the kinocilium and stereocilia alters conductance of ion channels, in turn affecting release of neurotransmitter onto the associated sensory axon. (These axons project along the auditory and vestibular nerves, cranial nerve VIII).<br />
<br />
=== Semicircular Canals ===<br />
<br />
Each semicircular canal of the bony labyrinth is a hollow passageway looping out from and back to the vestibule. Within each of these passageways is a semicircular canal of the membranous labyrinth. At one end of each membranous semicircular canal is a small enlargement called the ampulla. Within each ampulla is a ridge or "crest" called the crista that is covered with hair cells. A small mass of jelly, called the cupola ("cap") rests on top of the hair cells of the crista. The hair cells of the ampullae respond to angular acceleration (i.e., rotation of the head) <br />
<br />
There are three semicircular canals in each ear, oriented in three mutually-perpendicular planes. Rotation of the head in any direction will cause inertial fluid movement in one or more of the semicircular canals. <br />
<br />
=== Cochlea ===<br />
<br />
==== Slide 286, Ear Cochlea ====<br />
<br />
The cochlea houses an elaborate configuration of membranous labyrinth and hair cells, called the organ of Corti, designed for auditory reception. The basic shape of the cochlea is that of a snail-shell, or tapering helix. The spiraling tunnel that forms the cochlea of the bony labyrinth is divided into three distinct channels by portions of the membranous labyrinth attached to bony ridges. The central column of the helical cochlea contains axons serving the organ of Corti on their way to the auditory nerve. <br />
<br />
<peir-vm>UAB-Histology-00286</peir-vm><br />
<br />
=== Organ of Corti ===<br />
<br />
The organ of Corti is an elaborate structure with more named parts than the rest of inner ear. The organ of Corti is a long strip of tissue that extends the length of the scala media, from the base of the cochlea to its apex. Within the complex strip of tissue that comprises the organ of Corti are specialized sensory hair cells. The whole organ of Corti rests on the basilar membrane which supports the basal ends of the hair cells in the organ of Corti. The apical ends of hair cells touch the tectorial membrane, a "shelf" of jelly that is supported immovably on the spiral lamina. When the basilar membrane flexes in respond to sound waves (i.e., pressure waves delivered to inner-ear fluid by the middle-ear ossicles), the organ of Corti, including its hair cells, also moves. Thus, when the basilar membrane is moved by pressure waves (i.e., sound), the hair cells move relative to the tectorial membrane, causing stimulatory deflection of the apical ends of the hair cells.<br />
<br />
=== Endolymph and Perilymph ===<br />
<br />
The membranous labyrinth is filled with endolymph and is surrounded by perilymph. Endolymph is a unique fluid, with high K+ concentration and very low Na+ concentration. This endolymph provides the proper ionic environment for hair cell function. Endolymph is secreted by cells of the stria vascularis, along the scala media of the cochlea. <br />
<br />
In the vestibular system (surrounding the saccule, utricle, and semicircular canals), perilymph simply provides a cushioning support for the membranous labyrinth.<br />
<br />
In the cochlea, perilymph of the ascending scala vestibuli and the descending scala tympani conveys pressure waves (sound) across the scala media. Pressure waves flex the basilar membrane and thereby stimulate hair cells of the organ of Corti.<br />
<br />
<br />
{{Template:Histologic}}<br />
<br />
[[Category:Histologic]]</div>Matthew Andersonhttps://peir.path.uab.edu/index.php?title=Histologic:Chapter_18&diff=3266Histologic:Chapter 182014-07-21T23:05:03Z<p>Matthew Anderson: /* Mammary Gland */</p>
<hr />
<div>== Introduction ==<br />
[[File:HistologicChapter18Skin.jpg|thumb|200px|Skin]]<br />
The microanatomy of the skin varies from one region of the body to another. In studying the slides, compare the similarities as well as differences between skin obtained from different areas of the body.<br />
<br />
=== Slide 46, Thick Skin (H&E) ===<br />
<br />
On this slide of thick skin:<br />
<br />
Identify the layers of the epidermis: stratum basale, stratum spinosum, stratum granulosum, stratum lucidum (if present), and stratum corneum.<br />
<br />
Stratum basale. This is represented by a single layer of columnar or high cuboidal cells resting on the basement membrane. Note the arrangement and shape of this layer of cells and look for mitoses.<br />
<br />
Stratum spinosum. This stratum consists of several layers of polygonal-shaped cells located immediately above the stratum basale. At high power view the delicate processes or spines that project all around the spinous cells and hence the basis for their name: ‘prickle cells.’ These are desmosomes, not intercellular bridges as once believed.<br />
<br />
Stratum granulosum. In optimal areas it is seen that this stratum consists of 3-4 layers of squamous-shaped cells containing deeply basophilic granules in the cytoplasm. These are the keratohyalin granules, the first visible indication of the process of keratinization. Recall that the prime purpose of almost all of the cells of the epidermis (with the exception of some of the basal cells) is to become cornified or keratinized. Hence these cells with the keratohyalin granules as well as the spinous cells are referred to as keratinocytes. Another cell type that does not become keratinized is the melanocyte (recognized as the cell with the pale or clear cytoplasm, round dark nucleus, and located in the stratum basale layer). Melanocytes are better seen on slide 4 (thin skin).<br />
<br />
Stratum lucidum. Can be seen as a thin light blue or light green layer of cornified cells lying immediately above the stratum granulosum layer. <br />
<br />
With high magnification, it can be distinguished from the more basophilic layer of cornified tissue lying above it (stratum corneum).<br />
<br />
Stratum corneum. Note the overall thickness of this layer especially when compared with the stratum corneum of thin skin. Also note how much denser it is compared to the loose open weave of the cornified (keratinized) layers of thin skin. Observe the disorganized uppermost layers of the stratum corneum: these are the dead cornified layers being sloughed off (a constant process occurring all over the body surface).<br />
<br />
Dermis (Corium, Cutis). On the same slide, study the dermis and note that it is subdivided into the thin papillary layer and the thick reticular layer.<br />
<br />
Papillary layer (subepithelial). Observe the fine collagen fibers and some fine elastic fibers in this layer. Note the numerous blood vessels present in the papillae of the papillary layer. Most of these are capillaries forming loops extending up into the primary dermal papillae located between the epidermal ridges; these are “large” capillaries, somewhat wider in diameter than ordinary capillaries. Some of the vascular channels are lymphatic vessels (lymphatic capillaries). A rich lymph system is present in this part of the dermis, but difficult to clearly distinguish from venules or capillaries.<br />
<br />
Note an occasional tactile (Meissner’s) corpuscle present in the apical region of a dermal papilla. A Meissner’s corpuscle is an encapsulated sensory nerve ending for light touch (discriminating touch).<br />
<br />
Reticular layer. It is named because of the woven arrangement of the collagenous fibers (in the form of a close meshed net, that is, dense irregular connective tissue), not because it is composed of reticular fibers.<br />
<br />
Identify blood vessels, nerves, and ducts of sweat glands in the reticular layer. The small veins in thick skin generally have more smooth muscle in their tunica media than comparable veins elsewhere. Secretory units of eccrine sweat glands lie deep in the reticular layer; some are even found in the subcutaneous layer (called the hypodermis, but not part of skin proper). The subcutaneous layer of connective tissue also contains lobules of adipose tissue that are separated by strands of collagenous fibers.<br />
<br />
Locate clusters of sections of secretory units of eccrine sweat glands in the dermal-subcutaneous junctional region; each cluster represents one gland. These sweat glands are classified as simple coiled tubular glands. This means that each sweat gland has its own duct and that the secretory portion of the gland is a coiled tube.<br />
<br />
In the coiled tubular portion, the secretory cells are simple cuboidal or columnar epithelium and may show pigment or vacuoles in their cytoplasm. Although it may appear that the secretory cells form double layers, all of them touch the basement membrane except where myoepithelial cells intervene. Identify the latter. Only the dark, thin nucleus of the myoepithelial cell can be seen between the basement membrane and the base of the secretory cells. (These myoid or myoepithelial cells are more prominent in apocrine glands.)<br />
<br />
Ducts of these sweat glands begin in the coiled portion, then straighten out and pass upward through the dermis. They have a narrow lumen and are lined by two layers of small cells (stratified cuboidal but outer cells may be somewhat rectangular). They lose their epithelial structure as they spiral through the epidermis.<br />
<br />
<peir-vm>UAB-Histology-00046</peir-vm><br />
<br />
=== Thin skin: Slides 3, 4, 47, 48 ===<br />
<br />
==== Slide 4, Thin Skin (H&E) ====<br />
<br />
At different magnifications compare thin skin with the sections of thick skin previously studied. Note the extent of the dermis in thin skin (using lowest magnification). One identifying mark of thin skin (aside from the thinner epidermis) is the presence of hair follicles. Only a few are seen on slide 4 (many more are seen on slide 3: scalp).<br />
<br />
Which layers of the epidermis are present?<br />
<br />
Observe the relatively compact arrangement of the collagen fibers immediately beneath the epidermis and their looser arrangement in the deeper regions of the dermis. No distinctive papillary versus reticular layer of the dermis can be seen.<br />
<br />
Note the presence of melanocytes seen among the epithelial cells of the stratum basale. The melanocytes have pale to clear cytoplasm and dark nuclei. It is not possible to see the extent of the melanocytes' cytoplasmic processes that extend up into the spinous layer and surround one to several spinous cells. Pigment is transferred from the melanocytes to the spinous cells.<br />
<br />
<peir-vm>UAB-Histology-00004</peir-vm><br />
<br />
==== Slide 3, Scalp (H&E) ====<br />
<br />
From a 28-year old male.<br />
<br />
Note the presence of numerous hair follicles on this section of scalp; some sectioned longitudinally show how the stratified squamous epithelium of the epidermis continues as a downward growth to form the epidermal root sheath of the hair follicle. The dermal root sheath is present in favorable sections as an arrangement of the dermis which “follows” the outline of the epidermal root sheath. It is not necessary at this time to study the detailed microscopic anatomy of hair follicles, but be able to recognize sections of hair follicles. Try to identify the layers in cross or oblique sections of follicles.<br />
<br />
Observe the presence of numerous sebaceous glands, one or more associated with a hair follicle. Look for sections of erector (arrector pili) muscles (smooth muscle) also associated with hair follicles. The term pilosebaceous unit is given to a hair follicle plus its associated sebaceous gland(s). Note the fine lipid vacuoles in all but the most peripheral small cuboidal cells that rest on the basement membrane of the gland.<br />
<br />
The mode of secretion in which the entire cell is lost is called holocrine secretion, and is characteristic of sebaceous glands. Find a duct which connects with the alveolus (also called saccule) of a sebaceous gland. Ducts are lined by stratified squamous epithelium and open into hair follicles; sebum moves up the outside of the hair shaft and reaches the surface of the skin to lubricate it. In some locations (margins of the lips, nipple, glans penis, labia minora) sebaceous glands are not associated with hair follicles, but open directly onto the skin surface.<br />
<br />
Study eccrine sweat glands. They are located between hair follicles in the vicinity of the sebaceous glands. Identify their ducts and coiled secretory portions.<br />
<br />
Note the extensive hemorrhage in the deep subcutaneous tissue, the result of a skull fracture.<br />
<br />
<peir-vm>UAB-Histology-00003</peir-vm><br />
<br />
==== Slide 47, Axillary Skin (H&E) ====<br />
<br />
In addition to the presence of several pilosebaceous units, axillary skin also contains the two types of sudoriferous (sweat) glands: eccrine glands and apocrine glands. Both types of sweat glands are simple coiled tubular glands. The principal structural difference is that secretory portions of apocrine glands are much larger in diameter than the secretory portions of eccrine glands.<br />
<br />
Using different magnifications, study the secretory cells of the apocrine sweat glands. These cells are either cuboidal or columnar in shape and the round nucleus with a prominent nucleolus is located in the basilar portion of the cells. Secretory droplets accumulate in the more columnar cells (these droplets are better visualized on slide 48 (PASH) of axillary skin). The ducts are identical to those associated with the eccrine glands but empty into the upper portion of the hair follicle. Where do the eccrine gland ducts empty?<br />
<br />
With high magnification study the apical portions of the secretory cells of the apocrine sweat glands. Note how they bulge a considerable way into the lumen. In places they appear to have pinched off and produce the rounded droplets or globules of secretion present in the lumen. In the past, it was assumed that an apical portion of the cell actually was pinched off and discharged (“apocrine secretion”). According to current interpretation, this is probably an erroneous concept resulting from a fixation artifact. Thus, the so-called apocrine sweat gland should really be considered as a modified eccrine or merocrine gland.<br />
<br />
Identify the myoepithelial cells in the secretory portions of the apocrine sweat glands; usually only the nucleus can be seen.<br />
<br />
Identify eccrine sweat glands. The duct sections are distinct. The secretory cells are pale and vacuolated - a postmortem change.<br />
<br />
Identify sections of hair follicles, sebaceous glands, and look for erector pili muscles.<br />
<br />
<peir-vm>UAB-Histology-00047</peir-vm><br />
<br />
==== Slide 48, Axillary Skin (PASH) ====<br />
<br />
Note the abundant and prominent PAS-positive secretory material in the apices of apocrine secretory cells. Due to the oblique cut through several apocrine tubules, some of the secretory epithelium is torn away from the basement membrane.<br />
<br />
Note, however, the absence of large apocrine tubules such as were seen on slide 47. Instead, smaller tubules are seen lined by tall simple columnar epithelium whose apices are filled with PAS-positive material.<br />
<br />
Identify eccrine sweat glands. The ducts are distinct but the secretory cells have marked postmortem degeneration and are sloughing into the lumen.<br />
<br />
<peir-vm>UAB-Histology-00048</peir-vm><br />
<br />
== Mammary Gland ==<br />
[[File:HistologicChapter18Breast.jpg|thumb|200px|Mammary Gland]]<br />
The human mammary gland consists of 15-25 separate compound alveolar glands, each with its own branching duct system. Each of the intralobular ducts of one lobule drains into interlobular ducts, which in turn drain into one of the 15-25 lobar ducts (or lactiferous ducts) that empty separately on the surface of the nipple. The 15 to 25 individual glands or lobes are separated from each other by dense collagenous tissue and abundant adipose tissue, which is primarily responsible for the mass and shape of the breast.<br />
<br />
=== Slide 269, Mammary Gland (H&E) ===<br />
<br />
Slide 269, Mammary gland (H&E) is inactive mammary gland of an adult human female. Histologically, there is a great difference in the mammary gland depending on whether it is inactive, or from a pregnant or lactating individual. Other slides to be studied include inactive gland on slide 268 and two sections from active glands (slides 267 and 270).<br />
<br />
Note on slide 269 the large proportion of stroma (dense collagenous connective tissue and fat), the density of the stroma and the amount and distribution of fat.<br />
<br />
The stroma is modified around the ducts and ‘embryonic’ alveoli and consists of primitive connective tissue with large fibroblasts, fine fibers, some plasma cells and lymphocytes, abundant ground substance and more numerous blood vessels than elsewhere. This is the intralobular connective tissue.<br />
<br />
The interlobular connective tissue has much coarser collagen fibers, fewer fibroblasts, varying numbers of fat cells and fewer vessels.<br />
<br />
Study the characteristics of the parenchyma. It consists solely of isolated groups of intralobular ducts and a few interlobular ducts. The ducts are lined with cuboidal or columnar epithelium with myoepithelial cells between its base and the basement membrane.<br />
<br />
<peir-vm>UAB-Histology-00269</peir-vm><br />
<br />
=== Slide 268, Mammary Gland (Masson) ===<br />
<br />
Slide 268, Mammary gland (Masson) is tissue from the same inactive gland used to make slide 269. Here, with the Masson’s stain, the differences between intralobular duct connective tissue and interlobular duct connective tissue are more easily distinguishable.<br />
<br />
Again note the delicate connective tissue around the intralobular ducts and alveoli. The latter are termed “embryonic” because they resemble the alveoli seen in some infants at term, which are hormonally stimulated to produce “witch’s” milk.<br />
<br />
<peir-vm>UAB-Histology-00268</peir-vm><br />
<br />
=== Slide 270, Mammary Gland (H&E) ===<br />
<br />
Slide 270, Mammary gland is from a lactating gland.<br />
<br />
Note the tremendously increased proportion of glandular tissue to stroma and the resulting formation of lobes and lobules. Observe the branching of some of the secretory alveoli.<br />
<br />
The alveoli have a lumen varying from 50 to 100 μm in diameter lined with simple low cuboidal to low columnar epithelium.<br />
<br />
In both the alveolar ducts (intralobular) and the interlobular ducts can be seen stained secretory material (the denatured proteinaceous portion of milk). The same material fills almost all the lumina of the alveoli; the scalloped outline of the secretory material in the lumina of the alveoli is an artifact of the preparation.<br />
<br />
Note the large size of some of the intralobular ducts; they are large because they are distended with secretion. This ductal epithelium is simple low cuboidal. Some of the interlobular ducts are smaller than the intralobular (alveolar) ducts.<br />
<br />
The interlobular and perilobular stroma is still dense collagenous fibers.<br />
<br />
The primitive intralobular stroma has been largely “used up” to provide “room” for the increased numbers of alveoli and ducts, but traces of it remain.<br />
<br />
Note the increased number and size of blood vessels in both lobular and interlobular locations.<br />
<br />
<peir-vm>UAB-Histology-00270</peir-vm><br />
<br />
=== Slide 267, Mammary Gland (PASH) ===<br />
<br />
Slide 267, Mammary gland is from a lactating gland.<br />
<br />
The alveoli are circular and much smaller, on the average, than those seen in slide 270.<br />
<br />
Note the cuboidal epithelium lining the alveolar lumina, the vacuolated cytoplasm due to dissolved-out lipid and the PAS-positive material in the alveolar lumina.<br />
<br />
The nuclei of the myoepithelial cells are easier to locate on this slide; they appear as elongated, narrow structures located between the epithelial cell and the basement membrane. The cytoplasm of the myoepithelial cells does not stain with either PASH or H&E.<br />
<br />
Oxytocin, the milk letdown factor elaborated from the neurohypophysis, is a hormone that stimulates the myoepithelial cell to contract, and in so doing helps squeeze out or eject the milk from the alveoli.<br />
<br />
Until evidence from EM studies proved otherwise, the consensus among histologists and physiologists was that milk was produced as an apocrine type of secretion, that is, portions of the alveolar epithelial cell were believed to break off and form part of the secretory product. Current EM information indicates that the protein component of milk is released as a merocrine type of secretion. The process of protein release is called exocytosis.<br />
<br />
The lipid component of milk is released from the cell surrounded or enveloped by a membrane derived from the cell’s plasma membrane and an exceeding thin rim of cytoplasm. Technically, this type of secretions is of the apocrine method but the amount of cytoplasm lost is far less than classical histologists would describe for “typical” apocrine gland.”<br />
<br />
<peir-vm>UAB-Histology-00267</peir-vm><br />
<br />
== Nipple Microanatomy ==<br />
<br />
=== Slide 272, Nipple (Masson's) ===<br />
<br />
Slide 272, Nipple (Masson’s) is a section of nipple and part of the surrounding areolar tissue from a human female breast.<br />
<br />
Note the thin epidermal stratified squamous epithelium pierced by numerous “fingers” of dermal papillae. The latter are extremely long and branching particularly in the areolar region around the nipple.<br />
<br />
Observe the large sebaceous glands lying within the dermis. Some of these glands are part of hair follicles (pilosebaceous unit); others are free or independent of the hair follicle.<br />
<br />
Look for large lactiferous ducts, lined with two-layered stratified cuboidal or low columnar epithelium. Smaller ducts (which lead into the lactiferous duct) may be seen towards one side of the section. These ducts merge directly into alveolar or secreting portions (units) of the mammary gland, which are lined with simple cuboidal to low columnar epithelium.<br />
<br />
Numerous bundles of smooth muscles are oriented circumferentially (therefore most are seen cut in x-section) in the nipple at its base and longitudinally around the lactiferous duct. Contraction of the muscle allows the nipple to become erect. Nerve innervation of the nipple is primarily at the tip -not at its sides or in the areola. This is functionally significant because the infant’s sucking stimulus is required for continued normal lactation.<br />
<br />
<peir-vm>UAB-Histology-00272</peir-vm><br />
<br />
{{Template:Histologic}}<br />
<br />
[[Category:Histologic]]</div>Matthew Andersonhttps://peir.path.uab.edu/index.php?title=File:HistologicChapter18Breast.jpg&diff=3265File:HistologicChapter18Breast.jpg2014-07-21T23:04:41Z<p>Matthew Anderson: </p>
<hr />
<div></div>Matthew Andersonhttps://peir.path.uab.edu/index.php?title=Histologic:Chapter_18&diff=3264Histologic:Chapter 182014-07-21T23:02:06Z<p>Matthew Anderson: /* Introduction */</p>
<hr />
<div>== Introduction ==<br />
[[File:HistologicChapter18Skin.jpg|thumb|200px|Skin]]<br />
The microanatomy of the skin varies from one region of the body to another. In studying the slides, compare the similarities as well as differences between skin obtained from different areas of the body.<br />
<br />
=== Slide 46, Thick Skin (H&E) ===<br />
<br />
On this slide of thick skin:<br />
<br />
Identify the layers of the epidermis: stratum basale, stratum spinosum, stratum granulosum, stratum lucidum (if present), and stratum corneum.<br />
<br />
Stratum basale. This is represented by a single layer of columnar or high cuboidal cells resting on the basement membrane. Note the arrangement and shape of this layer of cells and look for mitoses.<br />
<br />
Stratum spinosum. This stratum consists of several layers of polygonal-shaped cells located immediately above the stratum basale. At high power view the delicate processes or spines that project all around the spinous cells and hence the basis for their name: ‘prickle cells.’ These are desmosomes, not intercellular bridges as once believed.<br />
<br />
Stratum granulosum. In optimal areas it is seen that this stratum consists of 3-4 layers of squamous-shaped cells containing deeply basophilic granules in the cytoplasm. These are the keratohyalin granules, the first visible indication of the process of keratinization. Recall that the prime purpose of almost all of the cells of the epidermis (with the exception of some of the basal cells) is to become cornified or keratinized. Hence these cells with the keratohyalin granules as well as the spinous cells are referred to as keratinocytes. Another cell type that does not become keratinized is the melanocyte (recognized as the cell with the pale or clear cytoplasm, round dark nucleus, and located in the stratum basale layer). Melanocytes are better seen on slide 4 (thin skin).<br />
<br />
Stratum lucidum. Can be seen as a thin light blue or light green layer of cornified cells lying immediately above the stratum granulosum layer. <br />
<br />
With high magnification, it can be distinguished from the more basophilic layer of cornified tissue lying above it (stratum corneum).<br />
<br />
Stratum corneum. Note the overall thickness of this layer especially when compared with the stratum corneum of thin skin. Also note how much denser it is compared to the loose open weave of the cornified (keratinized) layers of thin skin. Observe the disorganized uppermost layers of the stratum corneum: these are the dead cornified layers being sloughed off (a constant process occurring all over the body surface).<br />
<br />
Dermis (Corium, Cutis). On the same slide, study the dermis and note that it is subdivided into the thin papillary layer and the thick reticular layer.<br />
<br />
Papillary layer (subepithelial). Observe the fine collagen fibers and some fine elastic fibers in this layer. Note the numerous blood vessels present in the papillae of the papillary layer. Most of these are capillaries forming loops extending up into the primary dermal papillae located between the epidermal ridges; these are “large” capillaries, somewhat wider in diameter than ordinary capillaries. Some of the vascular channels are lymphatic vessels (lymphatic capillaries). A rich lymph system is present in this part of the dermis, but difficult to clearly distinguish from venules or capillaries.<br />
<br />
Note an occasional tactile (Meissner’s) corpuscle present in the apical region of a dermal papilla. A Meissner’s corpuscle is an encapsulated sensory nerve ending for light touch (discriminating touch).<br />
<br />
Reticular layer. It is named because of the woven arrangement of the collagenous fibers (in the form of a close meshed net, that is, dense irregular connective tissue), not because it is composed of reticular fibers.<br />
<br />
Identify blood vessels, nerves, and ducts of sweat glands in the reticular layer. The small veins in thick skin generally have more smooth muscle in their tunica media than comparable veins elsewhere. Secretory units of eccrine sweat glands lie deep in the reticular layer; some are even found in the subcutaneous layer (called the hypodermis, but not part of skin proper). The subcutaneous layer of connective tissue also contains lobules of adipose tissue that are separated by strands of collagenous fibers.<br />
<br />
Locate clusters of sections of secretory units of eccrine sweat glands in the dermal-subcutaneous junctional region; each cluster represents one gland. These sweat glands are classified as simple coiled tubular glands. This means that each sweat gland has its own duct and that the secretory portion of the gland is a coiled tube.<br />
<br />
In the coiled tubular portion, the secretory cells are simple cuboidal or columnar epithelium and may show pigment or vacuoles in their cytoplasm. Although it may appear that the secretory cells form double layers, all of them touch the basement membrane except where myoepithelial cells intervene. Identify the latter. Only the dark, thin nucleus of the myoepithelial cell can be seen between the basement membrane and the base of the secretory cells. (These myoid or myoepithelial cells are more prominent in apocrine glands.)<br />
<br />
Ducts of these sweat glands begin in the coiled portion, then straighten out and pass upward through the dermis. They have a narrow lumen and are lined by two layers of small cells (stratified cuboidal but outer cells may be somewhat rectangular). They lose their epithelial structure as they spiral through the epidermis.<br />
<br />
<peir-vm>UAB-Histology-00046</peir-vm><br />
<br />
=== Thin skin: Slides 3, 4, 47, 48 ===<br />
<br />
==== Slide 4, Thin Skin (H&E) ====<br />
<br />
At different magnifications compare thin skin with the sections of thick skin previously studied. Note the extent of the dermis in thin skin (using lowest magnification). One identifying mark of thin skin (aside from the thinner epidermis) is the presence of hair follicles. Only a few are seen on slide 4 (many more are seen on slide 3: scalp).<br />
<br />
Which layers of the epidermis are present?<br />
<br />
Observe the relatively compact arrangement of the collagen fibers immediately beneath the epidermis and their looser arrangement in the deeper regions of the dermis. No distinctive papillary versus reticular layer of the dermis can be seen.<br />
<br />
Note the presence of melanocytes seen among the epithelial cells of the stratum basale. The melanocytes have pale to clear cytoplasm and dark nuclei. It is not possible to see the extent of the melanocytes' cytoplasmic processes that extend up into the spinous layer and surround one to several spinous cells. Pigment is transferred from the melanocytes to the spinous cells.<br />
<br />
<peir-vm>UAB-Histology-00004</peir-vm><br />
<br />
==== Slide 3, Scalp (H&E) ====<br />
<br />
From a 28-year old male.<br />
<br />
Note the presence of numerous hair follicles on this section of scalp; some sectioned longitudinally show how the stratified squamous epithelium of the epidermis continues as a downward growth to form the epidermal root sheath of the hair follicle. The dermal root sheath is present in favorable sections as an arrangement of the dermis which “follows” the outline of the epidermal root sheath. It is not necessary at this time to study the detailed microscopic anatomy of hair follicles, but be able to recognize sections of hair follicles. Try to identify the layers in cross or oblique sections of follicles.<br />
<br />
Observe the presence of numerous sebaceous glands, one or more associated with a hair follicle. Look for sections of erector (arrector pili) muscles (smooth muscle) also associated with hair follicles. The term pilosebaceous unit is given to a hair follicle plus its associated sebaceous gland(s). Note the fine lipid vacuoles in all but the most peripheral small cuboidal cells that rest on the basement membrane of the gland.<br />
<br />
The mode of secretion in which the entire cell is lost is called holocrine secretion, and is characteristic of sebaceous glands. Find a duct which connects with the alveolus (also called saccule) of a sebaceous gland. Ducts are lined by stratified squamous epithelium and open into hair follicles; sebum moves up the outside of the hair shaft and reaches the surface of the skin to lubricate it. In some locations (margins of the lips, nipple, glans penis, labia minora) sebaceous glands are not associated with hair follicles, but open directly onto the skin surface.<br />
<br />
Study eccrine sweat glands. They are located between hair follicles in the vicinity of the sebaceous glands. Identify their ducts and coiled secretory portions.<br />
<br />
Note the extensive hemorrhage in the deep subcutaneous tissue, the result of a skull fracture.<br />
<br />
<peir-vm>UAB-Histology-00003</peir-vm><br />
<br />
==== Slide 47, Axillary Skin (H&E) ====<br />
<br />
In addition to the presence of several pilosebaceous units, axillary skin also contains the two types of sudoriferous (sweat) glands: eccrine glands and apocrine glands. Both types of sweat glands are simple coiled tubular glands. The principal structural difference is that secretory portions of apocrine glands are much larger in diameter than the secretory portions of eccrine glands.<br />
<br />
Using different magnifications, study the secretory cells of the apocrine sweat glands. These cells are either cuboidal or columnar in shape and the round nucleus with a prominent nucleolus is located in the basilar portion of the cells. Secretory droplets accumulate in the more columnar cells (these droplets are better visualized on slide 48 (PASH) of axillary skin). The ducts are identical to those associated with the eccrine glands but empty into the upper portion of the hair follicle. Where do the eccrine gland ducts empty?<br />
<br />
With high magnification study the apical portions of the secretory cells of the apocrine sweat glands. Note how they bulge a considerable way into the lumen. In places they appear to have pinched off and produce the rounded droplets or globules of secretion present in the lumen. In the past, it was assumed that an apical portion of the cell actually was pinched off and discharged (“apocrine secretion”). According to current interpretation, this is probably an erroneous concept resulting from a fixation artifact. Thus, the so-called apocrine sweat gland should really be considered as a modified eccrine or merocrine gland.<br />
<br />
Identify the myoepithelial cells in the secretory portions of the apocrine sweat glands; usually only the nucleus can be seen.<br />
<br />
Identify eccrine sweat glands. The duct sections are distinct. The secretory cells are pale and vacuolated - a postmortem change.<br />
<br />
Identify sections of hair follicles, sebaceous glands, and look for erector pili muscles.<br />
<br />
<peir-vm>UAB-Histology-00047</peir-vm><br />
<br />
==== Slide 48, Axillary Skin (PASH) ====<br />
<br />
Note the abundant and prominent PAS-positive secretory material in the apices of apocrine secretory cells. Due to the oblique cut through several apocrine tubules, some of the secretory epithelium is torn away from the basement membrane.<br />
<br />
Note, however, the absence of large apocrine tubules such as were seen on slide 47. Instead, smaller tubules are seen lined by tall simple columnar epithelium whose apices are filled with PAS-positive material.<br />
<br />
Identify eccrine sweat glands. The ducts are distinct but the secretory cells have marked postmortem degeneration and are sloughing into the lumen.<br />
<br />
<peir-vm>UAB-Histology-00048</peir-vm><br />
<br />
== Mammary Gland ==<br />
<br />
The human mammary gland consists of 15-25 separate compound alveolar glands, each with its own branching duct system. Each of the intralobular ducts of one lobule drains into interlobular ducts, which in turn drain into one of the 15-25 lobar ducts (or lactiferous ducts) that empty separately on the surface of the nipple. The 15 to 25 individual glands or lobes are separated from each other by dense collagenous tissue and abundant adipose tissue, which is primarily responsible for the mass and shape of the breast.<br />
<br />
=== Slide 269, Mammary Gland (H&E) ===<br />
<br />
Slide 269, Mammary gland (H&E) is inactive mammary gland of an adult human female. Histologically, there is a great difference in the mammary gland depending on whether it is inactive, or from a pregnant or lactating individual. Other slides to be studied include inactive gland on slide 268 and two sections from active glands (slides 267 and 270).<br />
<br />
Note on slide 269 the large proportion of stroma (dense collagenous connective tissue and fat), the density of the stroma and the amount and distribution of fat.<br />
<br />
The stroma is modified around the ducts and ‘embryonic’ alveoli and consists of primitive connective tissue with large fibroblasts, fine fibers, some plasma cells and lymphocytes, abundant ground substance and more numerous blood vessels than elsewhere. This is the intralobular connective tissue.<br />
<br />
The interlobular connective tissue has much coarser collagen fibers, fewer fibroblasts, varying numbers of fat cells and fewer vessels.<br />
<br />
Study the characteristics of the parenchyma. It consists solely of isolated groups of intralobular ducts and a few interlobular ducts. The ducts are lined with cuboidal or columnar epithelium with myoepithelial cells between its base and the basement membrane.<br />
<br />
<peir-vm>UAB-Histology-00269</peir-vm><br />
<br />
=== Slide 268, Mammary Gland (Masson) ===<br />
<br />
Slide 268, Mammary gland (Masson) is tissue from the same inactive gland used to make slide 269. Here, with the Masson’s stain, the differences between intralobular duct connective tissue and interlobular duct connective tissue are more easily distinguishable.<br />
<br />
Again note the delicate connective tissue around the intralobular ducts and alveoli. The latter are termed “embryonic” because they resemble the alveoli seen in some infants at term, which are hormonally stimulated to produce “witch’s” milk.<br />
<br />
<peir-vm>UAB-Histology-00268</peir-vm><br />
<br />
=== Slide 270, Mammary Gland (H&E) ===<br />
<br />
Slide 270, Mammary gland is from a lactating gland.<br />
<br />
Note the tremendously increased proportion of glandular tissue to stroma and the resulting formation of lobes and lobules. Observe the branching of some of the secretory alveoli.<br />
<br />
The alveoli have a lumen varying from 50 to 100 μm in diameter lined with simple low cuboidal to low columnar epithelium.<br />
<br />
In both the alveolar ducts (intralobular) and the interlobular ducts can be seen stained secretory material (the denatured proteinaceous portion of milk). The same material fills almost all the lumina of the alveoli; the scalloped outline of the secretory material in the lumina of the alveoli is an artifact of the preparation.<br />
<br />
Note the large size of some of the intralobular ducts; they are large because they are distended with secretion. This ductal epithelium is simple low cuboidal. Some of the interlobular ducts are smaller than the intralobular (alveolar) ducts.<br />
<br />
The interlobular and perilobular stroma is still dense collagenous fibers.<br />
<br />
The primitive intralobular stroma has been largely “used up” to provide “room” for the increased numbers of alveoli and ducts, but traces of it remain.<br />
<br />
Note the increased number and size of blood vessels in both lobular and interlobular locations.<br />
<br />
<peir-vm>UAB-Histology-00270</peir-vm><br />
<br />
=== Slide 267, Mammary Gland (PASH) ===<br />
<br />
Slide 267, Mammary gland is from a lactating gland.<br />
<br />
The alveoli are circular and much smaller, on the average, than those seen in slide 270.<br />
<br />
Note the cuboidal epithelium lining the alveolar lumina, the vacuolated cytoplasm due to dissolved-out lipid and the PAS-positive material in the alveolar lumina.<br />
<br />
The nuclei of the myoepithelial cells are easier to locate on this slide; they appear as elongated, narrow structures located between the epithelial cell and the basement membrane. The cytoplasm of the myoepithelial cells does not stain with either PASH or H&E.<br />
<br />
Oxytocin, the milk letdown factor elaborated from the neurohypophysis, is a hormone that stimulates the myoepithelial cell to contract, and in so doing helps squeeze out or eject the milk from the alveoli.<br />
<br />
Until evidence from EM studies proved otherwise, the consensus among histologists and physiologists was that milk was produced as an apocrine type of secretion, that is, portions of the alveolar epithelial cell were believed to break off and form part of the secretory product. Current EM information indicates that the protein component of milk is released as a merocrine type of secretion. The process of protein release is called exocytosis.<br />
<br />
The lipid component of milk is released from the cell surrounded or enveloped by a membrane derived from the cell’s plasma membrane and an exceeding thin rim of cytoplasm. Technically, this type of secretions is of the apocrine method but the amount of cytoplasm lost is far less than classical histologists would describe for “typical” apocrine gland.”<br />
<br />
<peir-vm>UAB-Histology-00267</peir-vm><br />
<br />
== Nipple Microanatomy ==<br />
<br />
=== Slide 272, Nipple (Masson's) ===<br />
<br />
Slide 272, Nipple (Masson’s) is a section of nipple and part of the surrounding areolar tissue from a human female breast.<br />
<br />
Note the thin epidermal stratified squamous epithelium pierced by numerous “fingers” of dermal papillae. The latter are extremely long and branching particularly in the areolar region around the nipple.<br />
<br />
Observe the large sebaceous glands lying within the dermis. Some of these glands are part of hair follicles (pilosebaceous unit); others are free or independent of the hair follicle.<br />
<br />
Look for large lactiferous ducts, lined with two-layered stratified cuboidal or low columnar epithelium. Smaller ducts (which lead into the lactiferous duct) may be seen towards one side of the section. These ducts merge directly into alveolar or secreting portions (units) of the mammary gland, which are lined with simple cuboidal to low columnar epithelium.<br />
<br />
Numerous bundles of smooth muscles are oriented circumferentially (therefore most are seen cut in x-section) in the nipple at its base and longitudinally around the lactiferous duct. Contraction of the muscle allows the nipple to become erect. Nerve innervation of the nipple is primarily at the tip -not at its sides or in the areola. This is functionally significant because the infant’s sucking stimulus is required for continued normal lactation.<br />
<br />
<peir-vm>UAB-Histology-00272</peir-vm><br />
<br />
{{Template:Histologic}}<br />
<br />
[[Category:Histologic]]</div>Matthew Andersonhttps://peir.path.uab.edu/index.php?title=File:HistologicChapter18Skin.jpg&diff=3263File:HistologicChapter18Skin.jpg2014-07-21T23:01:37Z<p>Matthew Anderson: </p>
<hr />
<div></div>Matthew Andersonhttps://peir.path.uab.edu/index.php?title=Template:Histologic&diff=3262Template:Histologic2014-07-21T22:59:48Z<p>Matthew Anderson: </p>
<hr />
<div>{{Navbox<br />
|name = Histologic<br />
|title = [[Histologic]]<br />
|bodyclass = hlist<br />
[[Histologic]]<br />
|group1 = [[Histologic:Chapter 1|Chapter 1]]<br />
|list1 =<br />
* [[Histologic:Chapter 1#Introduction|Introduction]]<br />
* [[Histologic:Chapter 1#Overview_of_Tissue_Preparation_and_Staining_for_Microscopy|Overview of Tissue Preparation and Staining for Microscopy]]<br />
* [[Histologic:Chapter 1#Using_Histologic|Using Histologic]]<br />
|group2 = [[Histologic:Chapter 2|Chapter 2]]<br />
|list2 =<br />
* [[Histologic:Chapter 2#Cells,_Organelles,_and_Inclusions|Cells, Organelles, and Inclusions]]<br />
* [[Histologic:Chapter 2#Mitosis|Mitosis]]<br />
|group3 = [[Histologic:Chapter 3|Chapter 3]]<br />
|list3 =<br />
* [[Histologic:Chapter 3#Introduction|Introduction]]<br />
* [[Histologic:Chapter 3#Simple_Epithelium|Simple Epithelium]]<br />
* [[Histologic:Chapter 3#Stratified_Epithelium|Stratified Epithelium]]<br />
|group4 = [[Histologic:Chapter 4|Chapter 4]]<br />
|list4 =<br />
* [[Histologic:Chapter 4#Introduction|Introduction]]<br />
* [[Histologic:Chapter 4#Loose_Connective_Tissue|Loose Connective Tissue]]<br />
* [[Histologic:Chapter 4#Dense_Connective_Tissue|Dense Connective Tissue]]<br />
* [[Histologic:Chapter 4#Adipose_Tissue|Adipose Tissue]]<br />
|group5 = [[Histologic:Chapter 5|Chapter 5]]<br />
|list5 =<br />
* [[Histologic:Chapter 5#Introduction|Introduction]]<br />
* [[Histologic:Chapter 5#Smooth_Muscle|Smooth Muscle]]<br />
* [[Histologic:Chapter 5#Skeletal_Muscle|Skeletal Muscle]]<br />
* [[Histologic:Chapter 5#Cardiac_Muscle|Cardiac Muscle]]<br />
|group6 = [[Histologic:Chapter 6|Chapter 6]]<br />
|list6 =<br />
* [[Histologic:Chapter 6#Introduction|Introduction]]<br />
* [[Histologic:Chapter 6#Nerve_Fibers_And_Nerves|Nerve Fibers And Nerves]]<br />
* [[Histologic:Chapter 6#Central_Nervous_System:_Brain|Central Nervous System: Brain]]<br />
* [[Histologic:Chapter 6#Spinal_Cord_-_General_Structure|Spinal Cord - General Structure]]<br />
* [[Histologic:Chapter 6#Sympathetic_Chain_Ganglion_With_Multipolar_Neurons|Sympathetic Chain Ganglion With Multipolar Neurons]]<br />
* [[Histologic:Chapter 6#Parasympathetic_Ganglia|Parasympathetic Ganglia]]<br />
|group7 = [[Histologic:Chapter 7|Chapter 7]]<br />
|list7 =<br />
* [[Histologic:Chapter 7#Introduction|Introduction]]<br />
* [[Histologic:Chapter 7#Blood_Smears|Blood Smears]]<br />
|group8 = [[Histologic:Chapter 8|Chapter 8]]<br />
|list8 =<br />
* [[Histologic:Chapter 8#Introduction|Introduction]]<br />
* [[Histologic:Chapter 8#Lymph_Nodes|Lymph Nodes]]<br />
* [[Histologic:Chapter 8#Thymus|Thymus]]<br />
* [[Histologic:Chapter 8#Tonsils|Tonsils]]<br />
* [[Histologic:Chapter 8#Spleen|Spleen]]<br />
|group9 = [[Histologic:Chapter 9|Chapter 9]]<br />
|list9 =<br />
* [[Histologic:Chapter 9#Introduction|Introduction]]<br />
* [[Histologic:Chapter 9#Small_Blood_Vessels|Small Blood Vessels]]<br />
* [[Histologic:Chapter 9#Medium-Sized_Blood_Vessels|Medium-Sized Blood Vessels]]<br />
* [[Histologic:Chapter 9#Large_Arteries|Large Arteries]]<br />
* [[Histologic:Chapter 9#Large_Veins|Large Veins]]<br />
|group10 = [[Histologic:Chapter 10|Chapter 10]]<br />
|list10 =<br />
* [[Histologic:Chapter 10#Olfactory_Area|Olfactory Area]]<br />
* [[Histologic:Chapter 10#Epiglottis|Epiglottis]]<br />
* [[Histologic:Chapter 10#Trachea|Trachea]]<br />
* [[Histologic:Chapter 10#Bronchi,_Bronchioles,_and_Lung|Bronchi, Bronchioles, and Lung]]<br />
|group11 = [[Histologic:Chapter 11|Chapter 11]]<br />
|list11 =<br />
* [[Histologic:Chapter 11#Lip|Lip]]<br />
* [[Histologic:Chapter 11#Tongue|Tongue]]<br />
* [[Histologic:Chapter 11#Salivary_Glands|Salivary Glands]]<br />
* [[Histologic:Chapter 11#Pancreas|Pancreas]]<br />
* [[Histologic:Chapter 11#Esophagus|Esophagus]]<br />
* [[Histologic:Chapter 11#Stomach|Stomach]]<br />
* [[Histologic:Chapter 11#Small_Intestine|Small Intestine]]<br />
* [[Histologic:Chapter 11#Pylorus-Duodenal_Junction|Pylorus-Duodenal Junction]]<br />
* [[Histologic:Chapter 11#Duodenum|Duodenum]]<br />
* [[Histologic:Chapter 11#Jejunum|Jejunum]]<br />
* [[Histologic:Chapter 11#Ileum|Ileum]]<br />
* [[Histologic:Chapter 11#Appendix|Appendix]]<br />
* [[Histologic:Chapter 11#Colon|Colon]]<br />
* [[Histologic:Chapter 11#Rectum|Rectum]]<br />
* [[Histologic:Chapter 11#Anal_Canal|Anal Canal]]<br />
|group12 = [[Histologic:Chapter 12|Chapter 12]]<br />
|list12 =<br />
* [[Histologic:Chapter 12#Introduction|Introduction]]<br />
* [[Histologic:Chapter 12#Gallbladder|Gallbladder]]<br />
|group13 = [[Histologic:Chapter 13|Chapter 13]]<br />
|list13 =<br />
* [[Histologic:Chapter 13#Skeletal_Muscle|Skeletal Muscle]]<br />
* [[Histologic:Chapter 13#Cartilage|Cartilage]]<br />
* [[Histologic:Chapter 13#Bone|Bone]]<br />
* [[Histologic:Chapter 13#Joints|Joints]]<br />
|group14 = [[Histologic:Chapter 14|Chapter 14]]<br />
|list14 =<br />
* [[Histologic:Chapter 14#Introduction|Introduction]]<br />
* [[Histologic:Chapter 14#Pituitary_Gland_(Hypophysis)|Pituitary Gland (Hypophysis)]]<br />
* [[Histologic:Chapter 14#Thyroid|Thyroid]]<br />
* [[Histologic:Chapter 14#Parathyroid|Parathyroid]]<br />
* [[Histologic:Chapter 14#Suprarenal_(Adrenal)_Glands|Suprarenal (Adrenal) Glands]]<br />
* [[Histologic:Chapter 14#Endocrine_Pancreas_(Pancreatic_Islets_of_Langerhans)|Endocrine Pancreas (Pancreatic Islets of Langerhans)]]<br />
|group15 = [[Histologic:Chapter 15|Chapter 15]]<br />
|list15 =<br />
* [[Histologic:Chapter 15#Kidney|Kidney]]<br />
* [[Histologic:Chapter 15#Ureter_and_Urinary_Bladder|Ureter And Urinary Bladder]]<br />
|group16 = [[Histologic:Chapter 16|Chapter 16]]<br />
|list16 =<br />
* [[Histologic:Chapter 16#Introduction|Introduction]]<br />
* [[Histologic:Chapter 16#The_Testis|The Testis]]<br />
* [[Histologic:Chapter 16#Genital_Ducts|Genital Ducts]]<br />
* [[Histologic:Chapter 16#Accessory_Glands|Accessory Glands]]<br />
* [[Histologic:Chapter 16#Penis|Penis]]<br />
|group17 = [[Histologic:Chapter 17|Chapter 17]]<br />
|list17 =<br />
* [[Histologic:Chapter 17#Introduction|Introduction]]<br />
* [[Histologic:Chapter 17#Ovary|Ovary]]<br />
* [[Histologic:Chapter 17#Uterine_Tube|Uterine Tube]]<br />
* [[Histologic:Chapter 17#Uterus|Uterus]]<br />
* [[Histologic:Chapter 17#Vagina|Vagina]]<br />
* [[Histologic:Chapter 17#Placenta_and_Umbilical_Cord|Placenta and Umbilical Cord]]<br />
* [[Histologic:Chapter 17#Umbilical_Cord|Umbilical Cord]]<br />
|group18 = [[Histologic:Chapter 18|Chapter 18]]<br />
|list18 =<br />
* [[Histologic:Chapter 18#Introduction|Introduction]]<br />
* [[Histologic:Chapter 18#Mammary_Gland|Mammary Gland]]<br />
* [[Histologic:Chapter 18#Nipple_Microanatomy|Nipple Microanatomy]]<br />
|group19 = [[Histologic:Chapter 19|Chapter 19]]<br />
|list19 =<br />
* [[Histologic:Chapter 19#Introduction|Introduction]]<br />
|group20 = [[Histologic:Contributors|Contributors]]<br />
|list20 =<br />
* [[Histologic:Contributors#Acknowledgements|Acknowledgements]]<br />
* [[Histologic:Contributors#Staff|Staff]]<br />
<br />
}}<noinclude><br />
<br />
[[Category:Histologic Templates]]<br />
[[Category:Histologic]]<br />
</noinclude></div>Matthew Andersonhttps://peir.path.uab.edu/index.php?title=Histologic&diff=3261Histologic2014-07-21T22:59:02Z<p>Matthew Anderson: </p>
<hr />
<div>Welcome to [[Histologic]], a constantly-updated, wiki-based comprehensive manual for the teaching of histology at the [http://www.uab.edu/medicine/home/ University of Alabama at Birmingham School of Medicine]. It integrates still images from the [{{SERVER}}/library PEIR Digital Library] and whole slide images from the [http://peir-vm.path.uab.edu PEIR-VM] project. For usage instructions, please see [[Histologic:Chapter 1|Chapter 1]]. To get in touch with us, please see [[Histologic:Contributors|Contributors]].<br />
<br />
== [[Histologic:Chapter 1|Chapter 1: Overview]] ==<br />
* [[Histologic:Chapter 1#Introduction|Introduction]]<br />
* [[Histologic:Chapter 1#Overview_of_Tissue_Preparation_and_Staining_for_Microscopy|Overview of Tissue Preparation and Staining for Microscopy]]<br />
* [[Histologic:Chapter 1#Using_Histologic|Using Histologic]]<br />
<br />
== [[Histologic:Chapter 2|Chapter 2: The Cell]] ==<br />
* [[Histologic:Chapter 2#Cells,_Organelles,_and_Inclusions|Cells, Organelles, and Inclusions]]<br />
* [[Histologic:Chapter 2#Mitosis|Mitosis]]<br />
<br />
== [[Histologic:Chapter 3|Chapter 3: Epithelial Cells]] ==<br />
* [[Histologic:Chapter 3#Introduction|Introduction]]<br />
* [[Histologic:Chapter 3#Simple_Epithelium|Simple Epithelium]]<br />
* [[Histologic:Chapter 3#Stratified_Epithelium|Stratified Epithelium]]<br />
<br />
== [[Histologic:Chapter 4|Chapter 4: Support Cells and the Extracellular Matrix]] ==<br />
* [[Histologic:Chapter 4#Introduction|Introduction]]<br />
* [[Histologic:Chapter 4#Loose_Connective_Tissue|Loose Connective Tissue]]<br />
* [[Histologic:Chapter 4#Dense_Connective_Tissue|Dense Connective Tissue]]<br />
* [[Histologic:Chapter 4#Adipose_Tissue|Adipose Tissue]]<br />
<br />
== [[Histologic:Chapter 5|Chapter 5: Contractile Cells]] ==<br />
* [[Histologic:Chapter 5#Introduction|Introduction]]<br />
* [[Histologic:Chapter 5#Smooth_Muscle|Smooth Muscle]]<br />
* [[Histologic:Chapter 5#Skeletal_Muscle|Skeletal Muscle]]<br />
* [[Histologic:Chapter 5#Cardiac_Muscle|Cardiac Muscle]]<br />
<br />
== [[Histologic:Chapter 6|Chapter 6: Nervous Tissue]] ==<br />
* [[Histologic:Chapter 6#Introduction|Introduction]]<br />
* [[Histologic:Chapter 6#Nerve_Fibers_And_Nerves|Nerve Fibers And Nerves]]<br />
* [[Histologic:Chapter 6#Central_Nervous_System:_Brain|Central Nervous System: Brain]]<br />
* [[Histologic:Chapter 6#Spinal_Cord_-_General_Structure|Spinal Cord - General Structure]]<br />
* [[Histologic:Chapter 6#Sympathetic_Chain_Ganglion_With_Multipolar_Neurons|Sympathetic Chain Ganglion With Multipolar Neurons]]<br />
* [[Histologic:Chapter 6#Parasympathetic_Ganglia|Parasympathetic Ganglia]]<br />
<br />
== [[Histologic:Chapter 7|Chapter 7: Blood Cells]] ==<br />
* [[Histologic:Chapter 7#Introduction|Introduction]]<br />
* [[Histologic:Chapter 7#Blood_Smears|Blood Smears]]<br />
<br />
== [[Histologic:Chapter 8|Chapter 8: Immune System]] ==<br />
* [[Histologic:Chapter 8#Introduction|Introduction]]<br />
* [[Histologic:Chapter 8#Lymph_Nodes|Lymph Nodes]]<br />
* [[Histologic:Chapter 8#Thymus|Thymus]]<br />
* [[Histologic:Chapter 8#Tonsils|Tonsils]]<br />
* [[Histologic:Chapter 8#Spleen|Spleen]]<br />
<br />
== [[Histologic:Chapter 9|Chapter 9: Blood and Lymphatic Circulatory Systems and Heart]] ==<br />
* [[Histologic:Chapter 9#Introduction|Introduction]]<br />
* [[Histologic:Chapter 9#Small_Blood_Vessels|Small Blood Vessels]]<br />
* [[Histologic:Chapter 9#Medium-Sized_Blood_Vessels|Medium-Sized Blood Vessels]]<br />
* [[Histologic:Chapter 9#Large_Arteries|Large Arteries]]<br />
* [[Histologic:Chapter 9#Large_Veins|Large Veins]]<br />
<br />
== [[Histologic:Chapter 10|Chapter 10: Respiratory System]] ==<br />
* [[Histologic:Chapter 10#Olfactory_Area|Olfactory Area]]<br />
* [[Histologic:Chapter 10#Epiglottis|Epiglottis]]<br />
* [[Histologic:Chapter 10#Trachea|Trachea]]<br />
* [[Histologic:Chapter 10#Bronchi,_Bronchioles,_and_Lung|Bronchi, Bronchioles, and Lung]]<br />
<br />
== [[Histologic:Chapter 11|Chapter 11: Alimentary Tract]] ==<br />
* [[Histologic:Chapter 11#Lip|Lip]]<br />
* [[Histologic:Chapter 11#Tongue|Tongue]]<br />
* [[Histologic:Chapter 11#Salivary_Glands|Salivary Glands]]<br />
* [[Histologic:Chapter 11#Pancreas|Pancreas]]<br />
* [[Histologic:Chapter 11#Esophagus|Esophagus]]<br />
* [[Histologic:Chapter 11#Stomach|Stomach]]<br />
* [[Histologic:Chapter 11#Small_Intestine|Small Intestine]]<br />
* [[Histologic:Chapter 11#Pylorus-Duodenal_Junction|Pylorus-Duodenal Junction]]<br />
* [[Histologic:Chapter 11#Duodenum|Duodenum]]<br />
* [[Histologic:Chapter 11#Jejunum|Jejunum]]<br />
* [[Histologic:Chapter 11#Ileum|Ileum]]<br />
* [[Histologic:Chapter 11#Appendix|Appendix]]<br />
* [[Histologic:Chapter 11#Colon|Colon]]<br />
* [[Histologic:Chapter 11#Rectum|Rectum]]<br />
* [[Histologic:Chapter 11#Anal_Canal|Anal Canal]]<br />
<br />
== [[Histologic:Chapter 12|Chapter 12: Liver]] ==<br />
* [[Histologic:Chapter 12#Introduction|Introduction]]<br />
* [[Histologic:Chapter 12#Gallbladder|Gallbladder]]<br />
<br />
== [[Histologic:Chapter 13|Chapter 13: Musculoskeletal System]] ==<br />
* [[Histologic:Chapter 13#Skeletal_Muscle|Skeletal Muscle]]<br />
* [[Histologic:Chapter 13#Cartilage|Cartilage]]<br />
* [[Histologic:Chapter 13#Bone|Bone]]<br />
* [[Histologic:Chapter 13#Joints|Joints]]<br />
<br />
== [[Histologic:Chapter 14|Chapter 14: Endocrine System]] ==<br />
* [[Histologic:Chapter 14#Introduction|Introduction]]<br />
* [[Histologic:Chapter 14#Pituitary_Gland_(Hypophysis)|Pituitary Gland (Hypophysis)]]<br />
* [[Histologic:Chapter 14#Thyroid|Thyroid]]<br />
* [[Histologic:Chapter 14#Parathyroid|Parathyroid]]<br />
* [[Histologic:Chapter 14#Suprarenal_(Adrenal)_Glands|Suprarenal (Adrenal) Glands]]<br />
* [[Histologic:Chapter 14#Endocrine_Pancreas_(Pancreatic_Islets_of_Langerhans)|Endocrine Pancreas (Pancreatic Islets of Langerhans)]]<br />
<br />
== [[Histologic:Chapter 15|Chapter 15: Urinary System]] ==<br />
* [[Histologic:Chapter 15#Kidney|Kidney]]<br />
* [[Histologic:Chapter 15#Ureter_and_Urinary_Bladder|Ureter And Urinary Bladder]]<br />
<br />
== [[Histologic:Chapter 16|Chapter 16: Male Reproductive System]] ==<br />
* [[Histologic:Chapter 16#Introduction|Introduction]]<br />
* [[Histologic:Chapter 16#The_Testis|The Testis]]<br />
* [[Histologic:Chapter 16#Genital_Ducts|Genital Ducts]]<br />
* [[Histologic:Chapter 16#Accessory_Glands|Accessory Glands]]<br />
* [[Histologic:Chapter 16#Penis|Penis]]<br />
<br />
== [[Histologic:Chapter 17|Chapter 17: Female Reproductive System]] ==<br />
* [[Histologic:Chapter 17#Introduction|Introduction]]<br />
* [[Histologic:Chapter 17#Ovary|Ovary]]<br />
* [[Histologic:Chapter 17#Uterine_Tube|Uterine Tube]]<br />
* [[Histologic:Chapter 17#Uterus|Uterus]]<br />
* [[Histologic:Chapter 17#Vagina|Vagina]]<br />
* [[Histologic:Chapter 17#Placenta_and_Umbilical_Cord|Placenta and Umbilical Cord]]<br />
* [[Histologic:Chapter 17#Umbilical_Cord|Umbilical Cord]]<br />
<br />
== [[Histologic:Chapter 18|Chapter 18: Skin and Breast]] ==<br />
* [[Histologic:Chapter 18#Introduction|Introduction]]<br />
* [[Histologic:Chapter 18#Mammary_Gland|Mammary Gland]]<br />
* [[Histologic:Chapter 18#Nipple_Microanatomy|Nipple Microanatomy]]<br />
<br />
== [[Histologic:Chapter 19|Chapter 19: Special Senses]] ==<br />
* [[Histologic:Chapter 19#Introduction|Introduction]]<br />
<br />
== [[Histologic:Contributors|Contributors]] ==<br />
* [[Histologic:Contributors#Acknowledgements|Acknowledgements]]<br />
* [[Histologic:Contributors#Staff|Staff]]<br />
<br />
[[Category:Histologic]]</div>Matthew Andersonhttps://peir.path.uab.edu/index.php?title=Histologic:Chapter_18&diff=3260Histologic:Chapter 182014-07-21T22:56:58Z<p>Matthew Anderson: Created page with "== Introduction == The microanatomy of the skin varies from one region of the body to another. In studying the slides, compare the similarities as well as differences between..."</p>
<hr />
<div>== Introduction ==<br />
<br />
The microanatomy of the skin varies from one region of the body to another. In studying the slides, compare the similarities as well as differences between skin obtained from different areas of the body.<br />
<br />
=== Slide 46, Thick Skin (H&E) ===<br />
<br />
On this slide of thick skin:<br />
<br />
Identify the layers of the epidermis: stratum basale, stratum spinosum, stratum granulosum, stratum lucidum (if present), and stratum corneum.<br />
<br />
Stratum basale. This is represented by a single layer of columnar or high cuboidal cells resting on the basement membrane. Note the arrangement and shape of this layer of cells and look for mitoses.<br />
<br />
Stratum spinosum. This stratum consists of several layers of polygonal-shaped cells located immediately above the stratum basale. At high power view the delicate processes or spines that project all around the spinous cells and hence the basis for their name: ‘prickle cells.’ These are desmosomes, not intercellular bridges as once believed.<br />
<br />
Stratum granulosum. In optimal areas it is seen that this stratum consists of 3-4 layers of squamous-shaped cells containing deeply basophilic granules in the cytoplasm. These are the keratohyalin granules, the first visible indication of the process of keratinization. Recall that the prime purpose of almost all of the cells of the epidermis (with the exception of some of the basal cells) is to become cornified or keratinized. Hence these cells with the keratohyalin granules as well as the spinous cells are referred to as keratinocytes. Another cell type that does not become keratinized is the melanocyte (recognized as the cell with the pale or clear cytoplasm, round dark nucleus, and located in the stratum basale layer). Melanocytes are better seen on slide 4 (thin skin).<br />
<br />
Stratum lucidum. Can be seen as a thin light blue or light green layer of cornified cells lying immediately above the stratum granulosum layer. <br />
<br />
With high magnification, it can be distinguished from the more basophilic layer of cornified tissue lying above it (stratum corneum).<br />
<br />
Stratum corneum. Note the overall thickness of this layer especially when compared with the stratum corneum of thin skin. Also note how much denser it is compared to the loose open weave of the cornified (keratinized) layers of thin skin. Observe the disorganized uppermost layers of the stratum corneum: these are the dead cornified layers being sloughed off (a constant process occurring all over the body surface).<br />
<br />
Dermis (Corium, Cutis). On the same slide, study the dermis and note that it is subdivided into the thin papillary layer and the thick reticular layer.<br />
<br />
Papillary layer (subepithelial). Observe the fine collagen fibers and some fine elastic fibers in this layer. Note the numerous blood vessels present in the papillae of the papillary layer. Most of these are capillaries forming loops extending up into the primary dermal papillae located between the epidermal ridges; these are “large” capillaries, somewhat wider in diameter than ordinary capillaries. Some of the vascular channels are lymphatic vessels (lymphatic capillaries). A rich lymph system is present in this part of the dermis, but difficult to clearly distinguish from venules or capillaries.<br />
<br />
Note an occasional tactile (Meissner’s) corpuscle present in the apical region of a dermal papilla. A Meissner’s corpuscle is an encapsulated sensory nerve ending for light touch (discriminating touch).<br />
<br />
Reticular layer. It is named because of the woven arrangement of the collagenous fibers (in the form of a close meshed net, that is, dense irregular connective tissue), not because it is composed of reticular fibers.<br />
<br />
Identify blood vessels, nerves, and ducts of sweat glands in the reticular layer. The small veins in thick skin generally have more smooth muscle in their tunica media than comparable veins elsewhere. Secretory units of eccrine sweat glands lie deep in the reticular layer; some are even found in the subcutaneous layer (called the hypodermis, but not part of skin proper). The subcutaneous layer of connective tissue also contains lobules of adipose tissue that are separated by strands of collagenous fibers.<br />
<br />
Locate clusters of sections of secretory units of eccrine sweat glands in the dermal-subcutaneous junctional region; each cluster represents one gland. These sweat glands are classified as simple coiled tubular glands. This means that each sweat gland has its own duct and that the secretory portion of the gland is a coiled tube.<br />
<br />
In the coiled tubular portion, the secretory cells are simple cuboidal or columnar epithelium and may show pigment or vacuoles in their cytoplasm. Although it may appear that the secretory cells form double layers, all of them touch the basement membrane except where myoepithelial cells intervene. Identify the latter. Only the dark, thin nucleus of the myoepithelial cell can be seen between the basement membrane and the base of the secretory cells. (These myoid or myoepithelial cells are more prominent in apocrine glands.)<br />
<br />
Ducts of these sweat glands begin in the coiled portion, then straighten out and pass upward through the dermis. They have a narrow lumen and are lined by two layers of small cells (stratified cuboidal but outer cells may be somewhat rectangular). They lose their epithelial structure as they spiral through the epidermis.<br />
<br />
<peir-vm>UAB-Histology-00046</peir-vm><br />
<br />
=== Thin skin: Slides 3, 4, 47, 48 ===<br />
<br />
==== Slide 4, Thin Skin (H&E) ====<br />
<br />
At different magnifications compare thin skin with the sections of thick skin previously studied. Note the extent of the dermis in thin skin (using lowest magnification). One identifying mark of thin skin (aside from the thinner epidermis) is the presence of hair follicles. Only a few are seen on slide 4 (many more are seen on slide 3: scalp).<br />
<br />
Which layers of the epidermis are present?<br />
<br />
Observe the relatively compact arrangement of the collagen fibers immediately beneath the epidermis and their looser arrangement in the deeper regions of the dermis. No distinctive papillary versus reticular layer of the dermis can be seen.<br />
<br />
Note the presence of melanocytes seen among the epithelial cells of the stratum basale. The melanocytes have pale to clear cytoplasm and dark nuclei. It is not possible to see the extent of the melanocytes' cytoplasmic processes that extend up into the spinous layer and surround one to several spinous cells. Pigment is transferred from the melanocytes to the spinous cells.<br />
<br />
<peir-vm>UAB-Histology-00004</peir-vm><br />
<br />
==== Slide 3, Scalp (H&E) ====<br />
<br />
From a 28-year old male.<br />
<br />
Note the presence of numerous hair follicles on this section of scalp; some sectioned longitudinally show how the stratified squamous epithelium of the epidermis continues as a downward growth to form the epidermal root sheath of the hair follicle. The dermal root sheath is present in favorable sections as an arrangement of the dermis which “follows” the outline of the epidermal root sheath. It is not necessary at this time to study the detailed microscopic anatomy of hair follicles, but be able to recognize sections of hair follicles. Try to identify the layers in cross or oblique sections of follicles.<br />
<br />
Observe the presence of numerous sebaceous glands, one or more associated with a hair follicle. Look for sections of erector (arrector pili) muscles (smooth muscle) also associated with hair follicles. The term pilosebaceous unit is given to a hair follicle plus its associated sebaceous gland(s). Note the fine lipid vacuoles in all but the most peripheral small cuboidal cells that rest on the basement membrane of the gland.<br />
<br />
The mode of secretion in which the entire cell is lost is called holocrine secretion, and is characteristic of sebaceous glands. Find a duct which connects with the alveolus (also called saccule) of a sebaceous gland. Ducts are lined by stratified squamous epithelium and open into hair follicles; sebum moves up the outside of the hair shaft and reaches the surface of the skin to lubricate it. In some locations (margins of the lips, nipple, glans penis, labia minora) sebaceous glands are not associated with hair follicles, but open directly onto the skin surface.<br />
<br />
Study eccrine sweat glands. They are located between hair follicles in the vicinity of the sebaceous glands. Identify their ducts and coiled secretory portions.<br />
<br />
Note the extensive hemorrhage in the deep subcutaneous tissue, the result of a skull fracture.<br />
<br />
<peir-vm>UAB-Histology-00003</peir-vm><br />
<br />
==== Slide 47, Axillary Skin (H&E) ====<br />
<br />
In addition to the presence of several pilosebaceous units, axillary skin also contains the two types of sudoriferous (sweat) glands: eccrine glands and apocrine glands. Both types of sweat glands are simple coiled tubular glands. The principal structural difference is that secretory portions of apocrine glands are much larger in diameter than the secretory portions of eccrine glands.<br />
<br />
Using different magnifications, study the secretory cells of the apocrine sweat glands. These cells are either cuboidal or columnar in shape and the round nucleus with a prominent nucleolus is located in the basilar portion of the cells. Secretory droplets accumulate in the more columnar cells (these droplets are better visualized on slide 48 (PASH) of axillary skin). The ducts are identical to those associated with the eccrine glands but empty into the upper portion of the hair follicle. Where do the eccrine gland ducts empty?<br />
<br />
With high magnification study the apical portions of the secretory cells of the apocrine sweat glands. Note how they bulge a considerable way into the lumen. In places they appear to have pinched off and produce the rounded droplets or globules of secretion present in the lumen. In the past, it was assumed that an apical portion of the cell actually was pinched off and discharged (“apocrine secretion”). According to current interpretation, this is probably an erroneous concept resulting from a fixation artifact. Thus, the so-called apocrine sweat gland should really be considered as a modified eccrine or merocrine gland.<br />
<br />
Identify the myoepithelial cells in the secretory portions of the apocrine sweat glands; usually only the nucleus can be seen.<br />
<br />
Identify eccrine sweat glands. The duct sections are distinct. The secretory cells are pale and vacuolated - a postmortem change.<br />
<br />
Identify sections of hair follicles, sebaceous glands, and look for erector pili muscles.<br />
<br />
<peir-vm>UAB-Histology-00047</peir-vm><br />
<br />
==== Slide 48, Axillary Skin (PASH) ====<br />
<br />
Note the abundant and prominent PAS-positive secretory material in the apices of apocrine secretory cells. Due to the oblique cut through several apocrine tubules, some of the secretory epithelium is torn away from the basement membrane.<br />
<br />
Note, however, the absence of large apocrine tubules such as were seen on slide 47. Instead, smaller tubules are seen lined by tall simple columnar epithelium whose apices are filled with PAS-positive material.<br />
<br />
Identify eccrine sweat glands. The ducts are distinct but the secretory cells have marked postmortem degeneration and are sloughing into the lumen.<br />
<br />
<peir-vm>UAB-Histology-00048</peir-vm><br />
<br />
== Mammary Gland ==<br />
<br />
The human mammary gland consists of 15-25 separate compound alveolar glands, each with its own branching duct system. Each of the intralobular ducts of one lobule drains into interlobular ducts, which in turn drain into one of the 15-25 lobar ducts (or lactiferous ducts) that empty separately on the surface of the nipple. The 15 to 25 individual glands or lobes are separated from each other by dense collagenous tissue and abundant adipose tissue, which is primarily responsible for the mass and shape of the breast.<br />
<br />
=== Slide 269, Mammary Gland (H&E) ===<br />
<br />
Slide 269, Mammary gland (H&E) is inactive mammary gland of an adult human female. Histologically, there is a great difference in the mammary gland depending on whether it is inactive, or from a pregnant or lactating individual. Other slides to be studied include inactive gland on slide 268 and two sections from active glands (slides 267 and 270).<br />
<br />
Note on slide 269 the large proportion of stroma (dense collagenous connective tissue and fat), the density of the stroma and the amount and distribution of fat.<br />
<br />
The stroma is modified around the ducts and ‘embryonic’ alveoli and consists of primitive connective tissue with large fibroblasts, fine fibers, some plasma cells and lymphocytes, abundant ground substance and more numerous blood vessels than elsewhere. This is the intralobular connective tissue.<br />
<br />
The interlobular connective tissue has much coarser collagen fibers, fewer fibroblasts, varying numbers of fat cells and fewer vessels.<br />
<br />
Study the characteristics of the parenchyma. It consists solely of isolated groups of intralobular ducts and a few interlobular ducts. The ducts are lined with cuboidal or columnar epithelium with myoepithelial cells between its base and the basement membrane.<br />
<br />
<peir-vm>UAB-Histology-00269</peir-vm><br />
<br />
=== Slide 268, Mammary Gland (Masson) ===<br />
<br />
Slide 268, Mammary gland (Masson) is tissue from the same inactive gland used to make slide 269. Here, with the Masson’s stain, the differences between intralobular duct connective tissue and interlobular duct connective tissue are more easily distinguishable.<br />
<br />
Again note the delicate connective tissue around the intralobular ducts and alveoli. The latter are termed “embryonic” because they resemble the alveoli seen in some infants at term, which are hormonally stimulated to produce “witch’s” milk.<br />
<br />
<peir-vm>UAB-Histology-00268</peir-vm><br />
<br />
=== Slide 270, Mammary Gland (H&E) ===<br />
<br />
Slide 270, Mammary gland is from a lactating gland.<br />
<br />
Note the tremendously increased proportion of glandular tissue to stroma and the resulting formation of lobes and lobules. Observe the branching of some of the secretory alveoli.<br />
<br />
The alveoli have a lumen varying from 50 to 100 μm in diameter lined with simple low cuboidal to low columnar epithelium.<br />
<br />
In both the alveolar ducts (intralobular) and the interlobular ducts can be seen stained secretory material (the denatured proteinaceous portion of milk). The same material fills almost all the lumina of the alveoli; the scalloped outline of the secretory material in the lumina of the alveoli is an artifact of the preparation.<br />
<br />
Note the large size of some of the intralobular ducts; they are large because they are distended with secretion. This ductal epithelium is simple low cuboidal. Some of the interlobular ducts are smaller than the intralobular (alveolar) ducts.<br />
<br />
The interlobular and perilobular stroma is still dense collagenous fibers.<br />
<br />
The primitive intralobular stroma has been largely “used up” to provide “room” for the increased numbers of alveoli and ducts, but traces of it remain.<br />
<br />
Note the increased number and size of blood vessels in both lobular and interlobular locations.<br />
<br />
<peir-vm>UAB-Histology-00270</peir-vm><br />
<br />
=== Slide 267, Mammary Gland (PASH) ===<br />
<br />
Slide 267, Mammary gland is from a lactating gland.<br />
<br />
The alveoli are circular and much smaller, on the average, than those seen in slide 270.<br />
<br />
Note the cuboidal epithelium lining the alveolar lumina, the vacuolated cytoplasm due to dissolved-out lipid and the PAS-positive material in the alveolar lumina.<br />
<br />
The nuclei of the myoepithelial cells are easier to locate on this slide; they appear as elongated, narrow structures located between the epithelial cell and the basement membrane. The cytoplasm of the myoepithelial cells does not stain with either PASH or H&E.<br />
<br />
Oxytocin, the milk letdown factor elaborated from the neurohypophysis, is a hormone that stimulates the myoepithelial cell to contract, and in so doing helps squeeze out or eject the milk from the alveoli.<br />
<br />
Until evidence from EM studies proved otherwise, the consensus among histologists and physiologists was that milk was produced as an apocrine type of secretion, that is, portions of the alveolar epithelial cell were believed to break off and form part of the secretory product. Current EM information indicates that the protein component of milk is released as a merocrine type of secretion. The process of protein release is called exocytosis.<br />
<br />
The lipid component of milk is released from the cell surrounded or enveloped by a membrane derived from the cell’s plasma membrane and an exceeding thin rim of cytoplasm. Technically, this type of secretions is of the apocrine method but the amount of cytoplasm lost is far less than classical histologists would describe for “typical” apocrine gland.”<br />
<br />
<peir-vm>UAB-Histology-00267</peir-vm><br />
<br />
== Nipple Microanatomy ==<br />
<br />
=== Slide 272, Nipple (Masson's) ===<br />
<br />
Slide 272, Nipple (Masson’s) is a section of nipple and part of the surrounding areolar tissue from a human female breast.<br />
<br />
Note the thin epidermal stratified squamous epithelium pierced by numerous “fingers” of dermal papillae. The latter are extremely long and branching particularly in the areolar region around the nipple.<br />
<br />
Observe the large sebaceous glands lying within the dermis. Some of these glands are part of hair follicles (pilosebaceous unit); others are free or independent of the hair follicle.<br />
<br />
Look for large lactiferous ducts, lined with two-layered stratified cuboidal or low columnar epithelium. Smaller ducts (which lead into the lactiferous duct) may be seen towards one side of the section. These ducts merge directly into alveolar or secreting portions (units) of the mammary gland, which are lined with simple cuboidal to low columnar epithelium.<br />
<br />
Numerous bundles of smooth muscles are oriented circumferentially (therefore most are seen cut in x-section) in the nipple at its base and longitudinally around the lactiferous duct. Contraction of the muscle allows the nipple to become erect. Nerve innervation of the nipple is primarily at the tip -not at its sides or in the areola. This is functionally significant because the infant’s sucking stimulus is required for continued normal lactation.<br />
<br />
<peir-vm>UAB-Histology-00272</peir-vm><br />
<br />
{{Template:Histologic}}<br />
<br />
[[Category:Histologic]]</div>Matthew Andersonhttps://peir.path.uab.edu/index.php?title=Histologic:Chapter_17&diff=3259Histologic:Chapter 172014-07-21T19:35:17Z<p>Matthew Anderson: /* Uterus */</p>
<hr />
<div>== Introduction ==<br />
<br />
The female reproductive system consists of the ovaries, the two uterine tubes (oviducts or Fallopian tubes) a uterus, a vagina, the external genitalia and the mammary glands. Normally, the development of this system requires that the zygote have the XX sex chromosomal complement. The ovaries produce the ova or female germ cells and certain hormones; the uterine tubes are necessary for transporting sperm to the ova for fertilization and for transporting the zygote to the uterus. Growth and maturation of the conceptus occur in the uterus. The vagina and external genitalia are the copulatory organs and the mammary glands serve for nutrition of the newborn.<br />
<br />
== Ovary ==<br />
[[File:HistologicChapter17Ovary.jpg|thumb|200px|Ovary]]<br />
With the exception of slide 255, Monkey ovary (PASH), all other slides were obtained from human sources.<br />
<br />
Study first slide 255 since it shows all the representative stages of follicle development. Then study slide 251, Ovary, (H&E); it has very small normal follicles, larger atretic follicles and corpora albicantia. Slide 254 Ovary (Masson) shows a large well-developed corpus luteum and a small atretic follicle with a prominent glassy membrane.<br />
<br />
=== Slide 255, Ovary (PASH) ===<br />
<br />
Slide 255, Ovary (PASH) shows a mature ovary with one large corpus luteum, several large preovulatory follicles, smaller growing follicles, and atretic follicles. Only a portion of the whole ovary is on the slide. <br />
<br />
Study the cortex of the ovary.<br />
<br />
Identify the surface epithelium (germinal epithelium), the tunica albuginea (a zone immediately beneath the surface epithelium which is more compact and less cellular than the stroma) and the stroma of cellular connective tissue.<br />
<br />
Study the various stages of follicles.<br />
<br />
Primordial (unilaminar follicles) consists of a small primary oocyte surrounded by a single layer of squamous follicular cells which rest on a basement membrane.<br />
<br />
A primary follicle contains an enlarging oocyte surrounded by a single layer of flattened, cuboidal or low columnar follicular cells. These cells give rise to granulosa cells by mitosis.<br />
<br />
Growing or multilaminar follicles are surrounded by several layers of follicular cells.<br />
<br />
Vesicular (secondary or antral) follicles consist of a primary oocyte surrounded by 6-12 layers of granulosa cells. Fluid-filled spaces that appear between the granulosa cells gradually enlarge, interconnect, and eventually form a crescent-shaped cavity, the antrum.<br />
<br />
Note the PAS-positive staining basement membrane located between the outer row of granulosa cells of the follicle and the stromal cells. Observe that the stromal cells are organized as a sheath of cells around the growing follicles.<br />
<br />
The vesicular follicles are surrounded by a stromal sheath called the theca folliculi; the theca is divided into two regions, a theca interna and a theca externa.<br />
<br />
The theca interna is a zone of epithelioid stromal cells surrounding the outer granulosa cells but separated from them by the basement membrane; this portion of the theca is vascular, containing capillaries and smaller blood vessels.<br />
<br />
The theca externa lies external to the theca interna and consists of condensed stroma.<br />
<br />
As the follicle enlarges, so does the oocyte. Increase in volume of both the nucleus and the cytoplasm accounts for oocyte enlargement. Observe the prominent nucleolus and the nuclear membrane of the oocytes; note that the cytoplasm is weakly acidophilic.<br />
<br />
The zone pellucida is a prominent PAS-positive staining membrane immediately surrounding the oocyte’s plasma membrane. It is not present in primordial follicles or in smaller growing follicles.<br />
<br />
The degeneration of follicles is called atresia and signs of this activity can be identified as follows:<br />
<br />
*The granulosa cell layer may be partially detached from the theca interna.<br />
*Groups of cells with pyknotic nuclei appear in the granulosa layer. <br />
*Fragmentation of the oocytes may be occurring.<br />
*The oocyte nucleus may be pyknotic (highly condensed and dark staining).<br />
*The basement membrane is very irregular, wavy, and fragmented. <br />
*The zone pellucida is fragmented or broken in places.<br />
<br />
Study the vesicular (secondary or antral) follicles.<br />
<br />
Identify early antrum formation in which the follicular cavity is small. Call-Exner bodies may be present between granulosal cells; they are strongly PAS-positive.<br />
<br />
Find a large follicle (large antrum) in which the large volume of the antrum indicates it is filled with fluid called liquor folliculi.<br />
<br />
The cumulus oophorus is a mound or hill of granulosa cells surrounding and supporting the large oocyte. This structure is present in the mature (Graafian) follicle.<br />
<br />
The corona radiata is a cluster of granulosal cells which immediately surrounds the zona pellucida. When the ovum breaks free from the cumulus oophorus the corona radiata cells “go with it” and surround the ovum during ovulation and transport into the uterine tube.<br />
<br />
Recall that just prior to ovulation, the primary oocyte undergoes its first maturation division, giving off the first polar body, to form a secondary oocyte. The final maturation division will not occur unless fertilization ensues.<br />
<br />
Study the corpus luteum.<br />
<br />
A corpus luteum is a new endocrine organ that makes its appearance after ovulation. The granulosa cells of the follicle hypertrophy, become luteinized and form granulosa lutein cells which secrete primarily progesterone. The corpus luteum on this slide is in an early stage of development. Note its large size. It consists of a thick folded wall and a central cavity (the former antrum of the follicle) which is filling in which fibrin deposits and loose connective tissue growing in from the theca externa. <br />
<br />
Most of the wall is composed of granulosa lutein cells derived from the granulosa cells of the mature follicle. They are large cells with pale cytoplasm and a vesicular nucleus containing a prominent nucleolus. The cell membrane is stained with PAS. The cells are packed closely together, but fibroblasts, fine connective tissue, and capillaries invading from the stroma are penetrating between the cells toward the central cavity.<br />
<br />
The theca lutein cells form a thin zone at the periphery of the corpus luteum and extend into the folds (which were formed when the ruptured follicle collapsed). They are not too apparent with this stain, but they are smaller cells than granulosa lutein cells.<br />
<br />
The former antrum has fibrin deposits and is filling in with loose connective tissue.<br />
<br />
The remains of atretic follicles can be seen as small irregular, intensely stained PAS-positive structures that are hypertrophied zona pellucida remnants from atretic follicles. They may or may not be surrounded by a greatly thickened folded glassy membrane (basement membrane) which stains pink. Both structures will be replaced by stroma.<br />
<br />
<br />
Study the medulla of the ovary.<br />
<br />
The medulla contains fibroelastic tissue, many large and smaller vessels, nerves, and lymphatics. Most of the blood vessels are highly coiled or convoluted.<br />
<br />
The medulla is continuous with the connective tissue of the mesovarium, a short peritoneal fold that attaches the ovary to the broad ligament; the point of attachment serves as a hilus for the ovary. The mesothelium of the serosa (visceral peritoneum) of the mesovarium is continuous with the surface epithelium of the ovary.<br />
<br />
A homologue to the rete testis in the male, the rete ovarii, can be seen in one part of the medulla (upper left in the field). They are distinguished by small, deeply basophilic nuclei of cuboidal cells lining an irregular-shaped lumen.<br />
<br />
<peir-vm>UAB-Histology-00255</peir-vm><br />
<br />
<br />
=== Slide 251, Ovary, Human (H&E) (From an elderly woman) === <br />
<br />
Study the cortex of this ovary.<br />
<br />
Note the prominent tunica albuginea just underneath the surface epithelium. The single layer of simple cuboidal cells making up the surface epithelium is present only in patches since part of it was sloughed off during preparation of the tissue.<br />
<br />
The stroma is much more evident on this slide as compared with the monkey ovary just studied. Note the swirling pattern of the stromal cells, especially how they begin to swirl and encircle a follicle some distance from the follicle. In growing follicles, the stromal cells begin to condense into the thecal follicular sheath of cells that contribute to the function of the follicle.<br />
<br />
Find primordial, primary and small growing follicles; (Primordial follicles are rare in mature ovaries). Note those follicles that show signs of atresia.<br />
<br />
The two or three large follicles (preovulatory follicles) on this slide are also in early atresia. Granulosa cells have sloughed off or are still sloughing; the basement membrane in one follicle is beginning to hypertrophy.<br />
<br />
Look for parts of corpora albicantia (singular = corpus albicans) which are fibrous scars that replace regressed corpora lutea; they are composed of compact collagenous fibers and fibroblasts, and have indefinite borders which merge with the stroma<br />
<br />
Study the medulla of this ovary. <br />
<br />
Note numerous, prominent blood vessels of various caliber which take up most of the volume of the medulla. Some of these vessels are quite convoluted (a long row of cross-sections of a vessel, each cross-section of about the same diameter, may be observed.<br />
<br />
Lymphatics are also a prominent feature of the ovarian medulla. They are more difficult to distinguish because their thin walls may have collapsed, eliminating the lumen.<br />
<br />
Vasomotor nerves to the smooth muscles of blood vessels may be seen; they are too small to see clearly.<br />
<br />
<peir-vm>UAB-Histology-00251</peir-vm><br />
<br />
<br />
=== Slide 254, Ovary, Human (Masson) ===<br />
<br />
The principal structure occupying most of this section is a corpus luteum. Other follicles may also be present, but concentrate on the corpus luteum.<br />
<br />
The corpus luteum represents a very young stage of development, soon after ovulation. The amount of connective tissue located in the middle of the corpus luteum indicates the age of the organ. Note the huge size of the corpus luteum; it occupies most of the section.<br />
<br />
Observe again that granulosa lutein cells make up the bulk of the corpus luteum; these are large cells with granular cytoplasm, vesicular nuclei and prominent nucleoli. Due to artifact of preparation or postmortem changes the cells are separated from each other by spaces.<br />
<br />
The granulosa lutein cells are arranged into groups separated by delicate strands of connective tissue and capillaries.<br />
<br />
In the central cavity are strands of clotted blood (red blood corpuscles and precipitated fibrin) and fine fibrin filaments. Little or no connective tissue is present as yet.<br />
<br />
Numerous dilated blood vessels are seen in the stroma around the periphery of the corpus luteum, probably still in this state from their preovulatory condition.<br />
<br />
The blue-staining connective tissue on the outer margin of the corpus luteum represents the former theca externa.<br />
<br />
Theca lutein cells are present on the periphery and in the folds of this corpus luteum but are not yet well differentiated, thus are not easily identified. Blood vessels and connective tissue will be growing in from the former theca externa.<br />
<br />
If fertilization does not take place, the corpus luteum persists for about two weeks, and then it breaks down (regresses) to become a corpus albicans. The corpus luteum in this case is called a corpus luteum spurium (false) or corpus luteum of menstruation.<br />
<br />
If fertilization occurs, the corpus luteum persists, gets larger, and lasts longer; it is now called a corpus luteum verum (true) or corpus luteum of pregnancy.<br />
<br />
<peir-vm>UAB-Histology-00254</peir-vm><br />
<br />
== Uterine Tube ==<br />
<br />
Each uterine tube is about 12 cm long and serves to connect the uterus with the ovaries for transport of spermatozoa, fertilization of the ovum and nourishment and transport of the zygote. The uterine tube is embedded in (courses through) the mesosalpinx which is the upper part of the broad ligament of the uterus. Within this mesentery of the uterine tube is a central core of connective tissue, some smooth muscle, blood vessels and nerves, and it is covered by a serosa (peritoneum). Thus the wall of the uterine tube consists of three layers: a mucosa, a muscularis and a serosa.<br />
<br />
Four regions of the uterine tube are generally recognized; from the uterus distally they are the interstitial (intramural) segment, the isthmus, the ampulla and the infundibulum. Only two regions or segments are represented in these slides. These are slides of the ampulla (slides 256, 257 and 258 and of the isthmus (slide 259).<br />
<br />
=== Slide 257, Uterine Tube Ampulla (Masson) ===<br />
<br />
Study the mucosa (mucous membrane) of this section of the uterine tube; note the complex foldings of the mucosa. The epithelium is actually simple columnar, but it frequently appears pseudostratified. It is tallest in the ampulla and decreases in height towards the uterus.<br />
<br />
The epithelium consists of two types of cells, ciliated columnar cells (numerous on the fimbria and in the ampulla) and non-ciliated columnar secretory cells (peg cells).<br />
<br />
The thin lamina propria is a primitive type of connective tissue, quite cellular; it extends into the folds. It is loosely arranged in the ampulla and is quite vascular. (It undergoes a decidual reaction, resembling decidual stromal cells found in the endometrium of the pregnant uterus, when tubal pregnancy occurs).<br />
<br />
Observe the muscularis (muscular coat). It has two ill-defined smooth muscle layers; the inner spiral circular layer is thicker than the outer longitudinal muscle layer. Fine connective tissue intermingles with smooth muscle cells.<br />
<br />
Surrounding the muscularis and intermingling with it is vascular connective tissue of the mesosalpinx. Note here the numerous greatly congested blood vessels of various diameters. Such congestion usually indicates a preovulatory state. A serosa forms the outermost layer.<br />
<br />
<peir-vm>UAB-Histology-00257</peir-vm><br />
<br />
=== Slide 258, Uterine Tube, Ampulla (PASH) ===<br />
<br />
This section of uterine tube is also from the ampulla in a pre-ovulatory state.<br />
<br />
The two epithelial cell types can be identified; there appear to be fewer ciliated cells (may be post-mortem loss). PAS clearly demonstrates basement membranes of the epithelial cells as well as elastic membranes in blood vessels.<br />
<br />
In the lamina propria, the looseness of the connective tissue in the folds is better demonstrated than in slide 257. Note branched fibroblasts and scattered lymphocytes. Lymphocytes may also be seen migrating through the epithelium to be eliminated from the body. Many dilated blood vessels are seen in this region.<br />
<br />
The muscularis appears as patches of smooth muscle fibers dispersed among a loose arrangement of connective tissue fibers. Numerous dilated blood vessels are interspersed in the connective tissue among the bundles of muscle fibers.<br />
<br />
<peir-vm>UAB-Histology-00258</peir-vm><br />
<br />
=== Slide 256, Uterine Tube (Ampulla) of Pregnancy (Masson) ===<br />
<br />
This section represents uterine tube removed from a pregnant woman. There are artifactual breaks in the tissue section. <br />
<br />
Identify the cell types in the epithelium. Nonciliated peg cells are most predominant, but this varies from place to place. The connective tissue of the lamina propria has proliferated to appear more like a primitive connective tissue; lymphocytes are more numerous. In the connective tissue you may be able to see large, pale-staining decidual cells which look like macrophages. These are glycogen storing cells that occur in great numbers in the uterus during pregnancy.<br />
<br />
Lymphocytes, decidual cells, and other cells appear to be working their way between the epithelial cells into the lumen, probably a reaction to an interrupted pregnancy. They are surrounded by a vacuole.<br />
<br />
Identify the layers of smooth muscle forming the muscularis, the numerous blood vessels in the connective tissue between the muscle bundles, and serosa covering most of the section.<br />
<br />
<peir-vm>UAB-Histology-00256</peir-vm><br />
<br />
=== Slide 259, Uterine Tube (Masson) ===<br />
<br />
This section is from the isthmus segment of the uterine tube, which lies along the uterine wall. Compare with slide 257, ampulla.<br />
<br />
Observe the size of the lumen, the degree of mucosal folding, the height of the epithelium and the width of the lamina propria and the muscularis. The mucosal foldings are much less complex than in the ampulla.<br />
<br />
Due to the thickness of this section of uterine tube its epithelium appears to be pseudostratified tall columnar. The nuclei are elongated and a few cells appear ciliated.<br />
<br />
The lamina propria is more compact in the isthmus than in the folds of the ampulla.<br />
<br />
Compare this section with that of the ductus deferens (slide 232) with which it might be confused. One should be able to distinguish them by the epithelium and by the layers of muscle.<br />
<br />
<peir-vm>UAB-Histology-00259</peir-vm><br />
<br />
<br />
== Uterus ==<br />
[[File:HistologicChapter17Uterus.jpg|thumb|200px|Uterus]]<br />
The uterine slides demonstrate two phases of the menstrual cycle and one of pregnancy. No slides are available from premenstrual and menstrual phases of the uterus.<br />
<br />
Slide 278 (H&E) is from the early proliferative phase.<br />
<br />
Slide 261 (H&E) is from the proliferative phase.<br />
<br />
Slide 262 (H&E) is from the secretory phase.<br />
<br />
Slide 264 (PASH) is from pregnant uterus; it shows decidual cells in the stroma and also has some placenta attached to it.<br />
<br />
=== Slide 278, Uterus, cross-section (H&E) ===<br />
<br />
Slide 278, Uterus, cross-section (H&E), shows endometrium in early to mid- proliferative phase of the menstrual cycle (days 7 to 9).<br />
<br />
Identify: endometrium (mucosa), myometrium (muscularis), and perimetrium (serosa).<br />
<br />
Study the endometrium.<br />
<br />
Distinguish two zones in the endometrium:<br />
<br />
*The basalis (deep layer) where the stroma is compact and glands are branched.<br />
<br />
*The functionalis, the entire endometrium above this. The stroma is not as compact as in the basal layer, but is quite dense in comparison with endometrium in later phases of the cycle.<br />
<br />
Note the simple columnar surface epithelium; it may appear pseudostratified but all nuclei are similar, therefore all cells are columnar. Occasional lymphocytes lying in a small vacuole are seen in the columnar cells.<br />
<br />
Simple tubular glands indent from the surface epithelium and extend through the thickness of the endometrium, becoming branched in their deepest parts. Some glands may extend into the myometrium for a short distance. The glandular epithelium is simple columnar that may also appear pseudostratified. Cytoplasm is very granular. Nuclei are basally located. Epithelium is proliferating; look for mitotic figures.<br />
<br />
The stroma is a “cellular” connective tissue, with fibroblasts with large oval nuclei and branching cell processes embedded in fine collagenous and reticular fibers. It resembles embryonic connective tissue. Some proliferation of fibroblasts is still in progress; look for mitotic figures. Some lymphocytes are present, especially in the most peripheral stroma. Note that the stroma is denser in the basal layer. This region remains relatively inactive.<br />
<br />
Look for coiled arteries in the lower fourth or third of the endometrium. Later, they will extend almost to the surface. A group of cross sections of these arterioles or very small arteries represents one coiled artery. Capillaries and venules are throughout the endometrium.<br />
<br />
Myometrium (muscularis).<br />
<br />
Note the thickness of the myometrium and the density of the muscle. Attempt to define the three layers of muscle but in a section it is difficult to do so.<br />
<br />
Stratum subvasculare, adjacent to the endometrium. Muscle fibers are in compact bundles, in cross or oblique sections (course longitudinally in the intact uterus), with prominent septa between them.<br />
<br />
Stratum vasculare, the middle layer, the thickest part of the muscularis. Interlacing bundles of muscle course both circularly and spirally.<br />
<br />
Note the large blood vessels in the deeper part of this stratum. Their peculiarities are normal for the uterus. These include muscle in the intima of the arteries, increased muscle in the media of the veins, and sometimes muscle in the adventitia of both. (Some arteries in this slide have arteriosclerosis or intimal hyalinzation.)<br />
<br />
Stratum supravasculare, the thin most peripheral layer, with longitudinal and circular fibers.<br />
<br />
Perimetrium (typical serosa): mesothelium and a little underlying loose connective tissue.<br />
<br />
<peir-vm>UAB-Histology-00278</peir-vm><br />
<br />
=== Slide 261, Uterus (H&E) ===<br />
<br />
Slide 261, Uterus (H&E), later proliferative phase, probably about days 10-12.<br />
<br />
Study the endometrium in comparison with slide 278.<br />
<br />
Note that the endometrium is a wider layer.<br />
<br />
Stroma is much less compact - more tissue fluid is present, fibroblasts are farther apart. Nearer the epithelium, stroma in places is beginning to have a spongy appearance.<br />
<br />
Glandular cells are larger, nuclei are large and vesicular, and epithelium appears pseudostratified. Secretion (glycogen, mucin) is beginning to accumulate at the bases of many cells. Small vacuolated areas represent the secretions that are removed during section preparation.<br />
<br />
Fibroblasts are seen more distinctly in the looser stroma; note their processes. Look for mitoses. Small lymphocytes are scattered throughout.<br />
<br />
Look for coiled arteries but they are not too prominent on this slide. Look for other small blood vessels.<br />
<br />
<peir-vm>UAB-Histology-00261</peir-vm><br />
<br />
=== Slide 262, Uterus (H&E) ===<br />
<br />
Slide 262, Uterus, (H&E) exhibits endometrium in a very late secretory phase or early premenstrual (probably days 24-26 of cycle; it is difficult to date precisely).<br />
<br />
Study the endometrium of this phase of the uterine cycle.<br />
<br />
Compare the width of the endometrium in this phase of the cycle with that in the previous slide.<br />
<br />
Note the characteristic large sacculated glands (“corkscrew appearance”). These are prominent throughout most of the functional zone. In the upper region of the functionalis zone (towards the surface) the glands have larger lumina but the sacculations in the walls are less.<br />
<br />
Note the position of the nuclei and the size of the glandular cells. Secretory material has moved from the infranuclear position to the supranuclear position, and some secretion has been liberated into the lumens of the glands. Therefore, the cells are smaller than in the earlier secretory stages, pseudostratification is much less apparent, and nuclei are basally located.<br />
<br />
Note areas of edema in the functional zone, but much of the excessive tissue fluid has already been resorbed.<br />
<br />
Note now the large size of the coiled arteries and their extent halfway or more upward into the functional zone.<br />
<br />
Observe the increased vascularity of capillaries and venules, especially in the outer functional zone. Some may already have ruptured.<br />
<br />
The surface epithelium is still intact.<br />
<br />
Note the myometrium and its blood vessels. Perimetrium is not present.<br />
<br />
<peir-vm>UAB-Histology-00262</peir-vm><br />
<br />
=== Slide 281, Cervix and OS Cervix, one wall (H&E) ===<br />
<br />
Slide shows endocervical epithelium and glands. The plane of section missed the junctional zone between endocervix and os cervix.<br />
<br />
Locate the os cervix (portio vaginalis) which is lined with stratified squamous epithelium. It can be seen grossly on the right margin of the section.<br />
<br />
Look along either surface of the section for cervical mucosa. The simple columnar lining epithelium consists of tall columnar cells, mucus-secreting; the luminal margin of the cells often appears indistinct or ragged. Note the Nabothian cyst (a cyst of a mucous gland of the cervix).<br />
<br />
The surface epithelium continues down to line the simple branched tubular mucus-secreting cervical glands.<br />
<br />
The lamina propria is no longer a primitive connective tissue as in the uterine endometrium.<br />
<br />
The mucosa is often folded, forming plicae palmatae.<br />
<br />
<peir-vm>UAB-Histology-00281</peir-vm><br />
<br />
== Vagina ==<br />
<br />
The vagina is a thick-walled fibromuscular tube that connects the uterus with the exterior and serves as a cavity for the reception of the penis at coitus and as a birth canal at the time of parturition.<br />
<br />
=== Slide 266, Vagina (H&E) ===<br />
<br />
The wall of the vagina consists of a mucosa, a muscularis, and a broad fibrosa that connects it to adjacent structures. The mucosa is thrown into broad folds (rugae) which are gross structures, not demonstrable in a small piece of tissue used for microscopic slides.<br />
<br />
Mucosa<br />
<br />
The epithelium is non-cornified stratified squamous. Note the stratum basale, the stratum spinosum, and the stratum corneum, so-called even though it is not cornified. The cells that appear empty contain glycogen and mucin, both of which are removed during routine section preparation.<br />
<br />
The broad areas of epithelium are tangential sections. Cross-sections of connective tissue papillae may be seen within them.<br />
<br />
Note connective tissue papillae projecting into the epithelium from the lamina propria. These are characteristic of most stratified squamous epithelia.<br />
<br />
The lamina propria is a broad zone of highly vascularized connective tissue, with abundant elastic fibers, extending to the muscularis. The elastic fibers may be seen as fine homogenous threads. (There is no muscularis mucosae or submucosa.) Note numerous small blood vessels and nerves. In many of the vessels, the endothelial cells (nuclei) are hypertrophied - not a normal condition.<br />
<br />
Scattered lymphocytes and plasma cells are seen throughout the mucosa. Lymphocytes may aggregate just below the epithelium to form diffuse lymphatic tissue or an occasional small nodule. Lymphocytes may penetrate the epithelium to migrate toward its surface.<br />
<br />
The muscularis, mostly arranged longitudinally, appears as bundles of smooth muscle interspersed with connective tissue rich in elastic fibers which may be seen as thin, homogenous threads. Larger blood vessels, as well as small ones, are found in the deep muscularis or fibrosa.<br />
<br />
The fibrosa is loose connective tissue. It should have some adipose tissue and nerves.<br />
<br />
<peir-vm>UAB-Histology-00266</peir-vm><br />
<br />
=== Slide 265, Vagina (Masson) ===<br />
<br />
Identify the regions of the wall and their component parts as in slide 266.<br />
<br />
Muscle and connective tissue are easily differentiated with Masson’s; they stain red and blue respectively. All nuclei stain red, as do erythrocytes. Elastic fibers are not distinguishable.<br />
<br />
The vascularity of the lamina propria is emphasized, with many of the venules congested.<br />
<br />
The large amount of connective tissue between the muscle bundles is well demonstrated.<br />
<br />
Lightly staining nerves occur among the muscle bundles and in the fibrosa.<br />
<br />
<peir-vm>UAB-Histology-00265</peir-vm><br />
<br />
== Placenta and Umbilical Cord ==<br />
<br />
Slides: 275, 264, 273, 274, 279, 280.<br />
<br />
=== Slide 275, Chorionic Villi (H&E) ===<br />
<br />
This is a section of a small part of a fetal placenta of a very early pregnancy, showing chorionic villi and the surrounding maternal blood spaces. Some slides have a strip of chorionic plate across the upper margin of the section.<br />
<br />
Chorionic plate<br />
<br />
The greater part of the plate is chorion, composed of a mass of embryonic connective tissue (large fibroblasts, fine collagenous fibers, abundant ground substance), covered on its lower surface by a double layer of epithelial cells: the cytotrophoblast adjacent to the connective tissue, and the syntrophoblast (syncytial trophoblast) on the free surface, bordering on maternal blood spaces.<br />
<br />
Cells of the syntrophoblast do not show cell boundaries. Ragged cell surfaces indicate microvilli. Cells of the cytotrophoblast supposedly show cell boundaries but they are not readily seen here. They divide to form syntrophoblast.<br />
<br />
Note blood vessels in the connective tissue (branches of umbilical vessels) containing nucleated fetal red blood corpuscles.<br />
<br />
The small zone of looser connective tissue in the upper part of the chorionic plate is part of the amnion. The cuboidal surface epithelium has been torn off.<br />
<br />
Chorionic villi. The villi are outgrowths from the chorion, having the same structure as the chorion. They increase in size and branch repeatedly as they invade the maternal blood spaces. The initial larger villi will become the anchoring villi that will penetrate the endometrium (decidua basalis) to anchor the fetal placenta. Smaller villi sprout off the anchoring villi.<br />
<br />
Note that the villi vary in size. The largest ones are potential anchoring villi. Others are floating villi; their free ends are in the blood spaces.<br />
<br />
Each villus has a core of embryonic connective tissue, branches of umbilical vessels (sparse in this early placenta), and a covering of inner cytotrophoblast and superficial syntrophoblast.<br />
<br />
<peir-vm>UAB-Histology-00275</peir-vm><br />
<br />
=== Slide 264, Uterus and Placenta from a later stage of pregnancy (PASH) === <br />
<br />
Look at the fetal placenta.<br />
<br />
Villi are larger and more numerous than in slide 275, stroma is generally more compact with more collagenous fibers (still fine) and abundant fibroblasts.<br />
<br />
Blood vessels in the villi are more numerous. Capillaries and little venules are peripherally located close to the trophoblast cells, although this may not be obvious due to plane of sections. Note that now red blood corpuscles are not nucleated.<br />
<br />
Syntrophoblast and cytotrophoblast are still present but cytotrophoblast is incomplete in many areas. (It will disappear entirely by late pregnancy.)<br />
<br />
Look for macrophages (Hofbauer cells) in the stroma of the villi - large rounded cells whose cytoplasm may have small vacuoles and/or PAS positive granules.<br />
<br />
Look for syncytial knots on the surface of villi or in the intervillous spaces. These are groups of syntrophoblast cells that detach from the villi and float freely in the spaces; progressively more are formed toward term.<br />
<br />
Look for very small deposits of fibrinoid, on or in the villi or in the intervillous spaces, a non-cellular, homogenous, proteinaceous material associated with transplantation immunity to protect the fetus.<br />
<br />
Maternal placenta (decidua basalis) and uterus. The decidua basalis is the name given to the endometrium that underlies the villi of the fetal placenta. Some villi (anchoring villi) penetrate the decidua basalis (endometrium) for varying distances. In doing so, part of the surface of the endometrium has been eroded and destroyed (surface epithelium is missing).<br />
<br />
Look for anchoring villi attaching to the decidua basalis. Note larger fibrinoid deposits and aggregations of syncytial knots in this region.<br />
<br />
In the decidua basalis, note the vast numbers of large and smaller decidual cells with PAS- positive cytoplasm (are storing glycogen) and large, lightly staining nuclei. Cytoplasm of those with less glycogen stains faintly acidophilic or somewhat grayish. Decidual cells are derived from fibroblasts of the endometrium.<br />
<br />
A few glands are seen in the basal zone of the endometrium. They may be dilated, have very low epithelium or hypertrophied epithelium, and have lymphocytic infiltration surrounding some of them.<br />
<br />
Identify the myometrium and note the large size of the muscle fibers that hypertrophy greatly during pregnancy.<br />
<br />
<peir-vm>UAB-Histology-00264</peir-vm><br />
<br />
=== Slide 280. Uterus and Placenta near term (H&E) ===<br />
<br />
Fetal placenta. Proliferation of villi has continued to increase during pregnancy.<br />
<br />
Note the great number of chorionic villi, practically filling the maternal blood spaces. The anchoring villi have become very large. The connective tissue in the core is fibrous, but embryonic connective tissue has persisted at the periphery. The larger blood vessels course in these villi. Observe the variation in size of the floating villi, which continue to form throughout pregnancy.<br />
<br />
In the villi, note further compactness of stroma, areas of more dense collagenous fibers, more capillaries, and venules close to the trophoblast.<br />
<br />
Look for macrophages (Hofbauer cells) in the stroma of the villi. With H&E, the cytoplasm is finely vacuolated.<br />
<br />
Syntrophoblasts still cover the surface of the villi. Cytotrophoblasts have generally disappeared.<br />
<br />
Note increased number of syncytial knots and much fibrinoid material. Knots are seen deep in the endometrium; they appear as darkly stained groups of pyknotic nuclei.<br />
<br />
The maternal placenta (decidua basalis).<br />
<br />
Again note the placental villi anchoring into the endometrium.<br />
<br />
Decidual cells are still present in the endometrium but many have “used up” their glycogen and are reverting to fibroblasts. Lymphocytic infiltration is seen in places. Much fibrinoid is present.<br />
<br />
Uterine glands, whose basal portions had remained inactive, are proliferating and regenerating. Some appear cystic.<br />
<br />
Uterine Muscularis.<br />
<br />
The three layers are not readily identified, but note again the large size of the fibers.<br />
<br />
Note the huge multinucleated giant cells in the deep endometrium and especially in the muscularis. They are thought to be of trophoblastic origin (perhaps differentiated from but not to be confused with syncytial knots).<br />
<br />
<peir-vm>UAB-Histology-00280</peir-vm><br />
<br />
=== Slide 279. Placenta at term (H&E) ===<br />
<br />
These slides are from a “fresh” placenta immediately after parturition; thus very little postmortem change is present and structures are seen distinctly.<br />
<br />
Go over the fetal placenta as in slide 280. Numerous red blood corpuscles are present in the maternal blood spaces, probably due to rupture of blood vessels during parturition.<br />
<br />
Note the tremendous vascularity of the placental villi, apparent here because of the fresh condition of the tissues; note also the great number of syncytial knots.<br />
<br />
A fragment of decidua basalis may be present (left end of the section in the field). Anchoring villi are seen and large decidual cells may still be present.<br />
<br />
<peir-vm>UAB-Histology-00279</peir-vm><br />
<br />
=== Slide 274, Placenta at term (PASH) ===<br />
<br />
This tissue is from the same placenta used for making slides 279 and 273. Look at the slide to see how term structures stain with PASH.<br />
<br />
Basement membranes are prominent under the syntrophoblast and under endothelium of the blood vessels. Note also that blood vessels are more numerous in these villi than in those of slide 280, are also congested which may be the cause of their large size.<br />
<br />
Areas of decidua basalis are present.<br />
<br />
<peir-vm>UAB-Histology-00274</peir-vm><br />
<br />
=== Slide 273, Placenta, term (Masson) ===<br />
<br />
This tissue is from the same placenta as used for making slides 274 and 279.<br />
<br />
Identify the structures as seen with this stain. Connective tissue elements are blue, nuclei are reddish or indistinct, and the cytoplasm varies. <br />
<br />
This section shows the chorionic plate at the right (in the field).<br />
<br />
The outer “membrane” is the amnion, consisting of a layer of cuboidal or low columnar epithelium and a thin layer of connective tissue. It is mechanically separated from the underlying chorion.<br />
<br />
The chorion consists of a layer of connective tissue covered by syncytial trophoblast that is now mostly fibrinoid.<br />
<br />
Two main umbilical vessels and smaller branches are passing through the chorionic plate.<br />
<br />
<peir-vm>UAB-Histology-00273</peir-vm><br />
<br />
== Umbilical Cord ==<br />
<br />
=== Slide 287, Umbilical Cords (H&E) ===<br />
<br />
Slide 287, Umbilical Cords (H&E), is from an early pregnancy and from late in pregnancy.<br />
<br />
The early pregnancy umbilical cord is on the left. The two umbilical arteries and the umbilical vein look generally similar because of the atypical large amount of muscle in the wall. An internal elastic membrane is lacking in the arteries. The diameter of the vein is greater than that of the artery and the muscle is not quite as compactly arranged.<br />
<br />
The stroma of the cord is mucous connective tissue - embryonic connective tissue with a mucoid ground substance (Wharton’s jelly) which is removed in section preparation. Note the fine collagenous fibers and the large branched fibroblasts.<br />
<br />
Covering the cord is simple squamous or simple cuboidal epithelium, part of the amnion.<br />
<br />
<peir-vm>UAB-Histology-00287</peir-vm><br />
<br />
=== Slides 287 (tissue on right) and Slide 277, umbilical cord at term (H&E) ===<br />
<br />
In this fully developed placenta, the atypical structure of the arteries is well shown - a wide inner layer of longitudinally arranged muscle and a thick outer circular layer. Postmortem contraction causes collapse of the vessels. The vein has some inner longitudinal muscle; most of it is outer circular. Reticular fibers between muscle fibers are seen with H&E (due to postmortem shrinkage of muscle fibers). The small vacuoles are probably early degenerative changes.<br />
<br />
Collagenous fibers in the stroma are somewhat heavier than in the earlier cord but are not mature fibers. Mucous connective tissue retains its embryonic nature; note that fibroblasts are still large branched cells.<br />
<br />
Neutrophils are invading some areas of the stroma (lower field especially), also related to breakdown of the tissues.<br />
<br />
Epithelium of the amnion surrounds the cord.<br />
<br />
==== Slide 287, Umbilical Cord at term (tissue on right) (H&E) ====<br />
<peir-vm>UAB-Histology-00287</peir-vm><br />
==== Slide 277, Umbilical Cord at term (H&E) ====<br />
<peir-vm>UAB-Histology-00277</peir-vm><br />
<br />
{{Template:Histologic}}<br />
<br />
[[Category:Histologic]]</div>Matthew Andersonhttps://peir.path.uab.edu/index.php?title=File:HistologicChapter17Uterus.jpg&diff=3258File:HistologicChapter17Uterus.jpg2014-07-21T19:35:01Z<p>Matthew Anderson: </p>
<hr />
<div></div>Matthew Andersonhttps://peir.path.uab.edu/index.php?title=Histologic:Chapter_17&diff=3257Histologic:Chapter 172014-07-21T19:31:54Z<p>Matthew Anderson: /* Ovary */</p>
<hr />
<div>== Introduction ==<br />
<br />
The female reproductive system consists of the ovaries, the two uterine tubes (oviducts or Fallopian tubes) a uterus, a vagina, the external genitalia and the mammary glands. Normally, the development of this system requires that the zygote have the XX sex chromosomal complement. The ovaries produce the ova or female germ cells and certain hormones; the uterine tubes are necessary for transporting sperm to the ova for fertilization and for transporting the zygote to the uterus. Growth and maturation of the conceptus occur in the uterus. The vagina and external genitalia are the copulatory organs and the mammary glands serve for nutrition of the newborn.<br />
<br />
== Ovary ==<br />
[[File:HistologicChapter17Ovary.jpg|thumb|200px|Ovary]]<br />
With the exception of slide 255, Monkey ovary (PASH), all other slides were obtained from human sources.<br />
<br />
Study first slide 255 since it shows all the representative stages of follicle development. Then study slide 251, Ovary, (H&E); it has very small normal follicles, larger atretic follicles and corpora albicantia. Slide 254 Ovary (Masson) shows a large well-developed corpus luteum and a small atretic follicle with a prominent glassy membrane.<br />
<br />
=== Slide 255, Ovary (PASH) ===<br />
<br />
Slide 255, Ovary (PASH) shows a mature ovary with one large corpus luteum, several large preovulatory follicles, smaller growing follicles, and atretic follicles. Only a portion of the whole ovary is on the slide. <br />
<br />
Study the cortex of the ovary.<br />
<br />
Identify the surface epithelium (germinal epithelium), the tunica albuginea (a zone immediately beneath the surface epithelium which is more compact and less cellular than the stroma) and the stroma of cellular connective tissue.<br />
<br />
Study the various stages of follicles.<br />
<br />
Primordial (unilaminar follicles) consists of a small primary oocyte surrounded by a single layer of squamous follicular cells which rest on a basement membrane.<br />
<br />
A primary follicle contains an enlarging oocyte surrounded by a single layer of flattened, cuboidal or low columnar follicular cells. These cells give rise to granulosa cells by mitosis.<br />
<br />
Growing or multilaminar follicles are surrounded by several layers of follicular cells.<br />
<br />
Vesicular (secondary or antral) follicles consist of a primary oocyte surrounded by 6-12 layers of granulosa cells. Fluid-filled spaces that appear between the granulosa cells gradually enlarge, interconnect, and eventually form a crescent-shaped cavity, the antrum.<br />
<br />
Note the PAS-positive staining basement membrane located between the outer row of granulosa cells of the follicle and the stromal cells. Observe that the stromal cells are organized as a sheath of cells around the growing follicles.<br />
<br />
The vesicular follicles are surrounded by a stromal sheath called the theca folliculi; the theca is divided into two regions, a theca interna and a theca externa.<br />
<br />
The theca interna is a zone of epithelioid stromal cells surrounding the outer granulosa cells but separated from them by the basement membrane; this portion of the theca is vascular, containing capillaries and smaller blood vessels.<br />
<br />
The theca externa lies external to the theca interna and consists of condensed stroma.<br />
<br />
As the follicle enlarges, so does the oocyte. Increase in volume of both the nucleus and the cytoplasm accounts for oocyte enlargement. Observe the prominent nucleolus and the nuclear membrane of the oocytes; note that the cytoplasm is weakly acidophilic.<br />
<br />
The zone pellucida is a prominent PAS-positive staining membrane immediately surrounding the oocyte’s plasma membrane. It is not present in primordial follicles or in smaller growing follicles.<br />
<br />
The degeneration of follicles is called atresia and signs of this activity can be identified as follows:<br />
<br />
*The granulosa cell layer may be partially detached from the theca interna.<br />
*Groups of cells with pyknotic nuclei appear in the granulosa layer. <br />
*Fragmentation of the oocytes may be occurring.<br />
*The oocyte nucleus may be pyknotic (highly condensed and dark staining).<br />
*The basement membrane is very irregular, wavy, and fragmented. <br />
*The zone pellucida is fragmented or broken in places.<br />
<br />
Study the vesicular (secondary or antral) follicles.<br />
<br />
Identify early antrum formation in which the follicular cavity is small. Call-Exner bodies may be present between granulosal cells; they are strongly PAS-positive.<br />
<br />
Find a large follicle (large antrum) in which the large volume of the antrum indicates it is filled with fluid called liquor folliculi.<br />
<br />
The cumulus oophorus is a mound or hill of granulosa cells surrounding and supporting the large oocyte. This structure is present in the mature (Graafian) follicle.<br />
<br />
The corona radiata is a cluster of granulosal cells which immediately surrounds the zona pellucida. When the ovum breaks free from the cumulus oophorus the corona radiata cells “go with it” and surround the ovum during ovulation and transport into the uterine tube.<br />
<br />
Recall that just prior to ovulation, the primary oocyte undergoes its first maturation division, giving off the first polar body, to form a secondary oocyte. The final maturation division will not occur unless fertilization ensues.<br />
<br />
Study the corpus luteum.<br />
<br />
A corpus luteum is a new endocrine organ that makes its appearance after ovulation. The granulosa cells of the follicle hypertrophy, become luteinized and form granulosa lutein cells which secrete primarily progesterone. The corpus luteum on this slide is in an early stage of development. Note its large size. It consists of a thick folded wall and a central cavity (the former antrum of the follicle) which is filling in which fibrin deposits and loose connective tissue growing in from the theca externa. <br />
<br />
Most of the wall is composed of granulosa lutein cells derived from the granulosa cells of the mature follicle. They are large cells with pale cytoplasm and a vesicular nucleus containing a prominent nucleolus. The cell membrane is stained with PAS. The cells are packed closely together, but fibroblasts, fine connective tissue, and capillaries invading from the stroma are penetrating between the cells toward the central cavity.<br />
<br />
The theca lutein cells form a thin zone at the periphery of the corpus luteum and extend into the folds (which were formed when the ruptured follicle collapsed). They are not too apparent with this stain, but they are smaller cells than granulosa lutein cells.<br />
<br />
The former antrum has fibrin deposits and is filling in with loose connective tissue.<br />
<br />
The remains of atretic follicles can be seen as small irregular, intensely stained PAS-positive structures that are hypertrophied zona pellucida remnants from atretic follicles. They may or may not be surrounded by a greatly thickened folded glassy membrane (basement membrane) which stains pink. Both structures will be replaced by stroma.<br />
<br />
<br />
Study the medulla of the ovary.<br />
<br />
The medulla contains fibroelastic tissue, many large and smaller vessels, nerves, and lymphatics. Most of the blood vessels are highly coiled or convoluted.<br />
<br />
The medulla is continuous with the connective tissue of the mesovarium, a short peritoneal fold that attaches the ovary to the broad ligament; the point of attachment serves as a hilus for the ovary. The mesothelium of the serosa (visceral peritoneum) of the mesovarium is continuous with the surface epithelium of the ovary.<br />
<br />
A homologue to the rete testis in the male, the rete ovarii, can be seen in one part of the medulla (upper left in the field). They are distinguished by small, deeply basophilic nuclei of cuboidal cells lining an irregular-shaped lumen.<br />
<br />
<peir-vm>UAB-Histology-00255</peir-vm><br />
<br />
<br />
=== Slide 251, Ovary, Human (H&E) (From an elderly woman) === <br />
<br />
Study the cortex of this ovary.<br />
<br />
Note the prominent tunica albuginea just underneath the surface epithelium. The single layer of simple cuboidal cells making up the surface epithelium is present only in patches since part of it was sloughed off during preparation of the tissue.<br />
<br />
The stroma is much more evident on this slide as compared with the monkey ovary just studied. Note the swirling pattern of the stromal cells, especially how they begin to swirl and encircle a follicle some distance from the follicle. In growing follicles, the stromal cells begin to condense into the thecal follicular sheath of cells that contribute to the function of the follicle.<br />
<br />
Find primordial, primary and small growing follicles; (Primordial follicles are rare in mature ovaries). Note those follicles that show signs of atresia.<br />
<br />
The two or three large follicles (preovulatory follicles) on this slide are also in early atresia. Granulosa cells have sloughed off or are still sloughing; the basement membrane in one follicle is beginning to hypertrophy.<br />
<br />
Look for parts of corpora albicantia (singular = corpus albicans) which are fibrous scars that replace regressed corpora lutea; they are composed of compact collagenous fibers and fibroblasts, and have indefinite borders which merge with the stroma<br />
<br />
Study the medulla of this ovary. <br />
<br />
Note numerous, prominent blood vessels of various caliber which take up most of the volume of the medulla. Some of these vessels are quite convoluted (a long row of cross-sections of a vessel, each cross-section of about the same diameter, may be observed.<br />
<br />
Lymphatics are also a prominent feature of the ovarian medulla. They are more difficult to distinguish because their thin walls may have collapsed, eliminating the lumen.<br />
<br />
Vasomotor nerves to the smooth muscles of blood vessels may be seen; they are too small to see clearly.<br />
<br />
<peir-vm>UAB-Histology-00251</peir-vm><br />
<br />
<br />
=== Slide 254, Ovary, Human (Masson) ===<br />
<br />
The principal structure occupying most of this section is a corpus luteum. Other follicles may also be present, but concentrate on the corpus luteum.<br />
<br />
The corpus luteum represents a very young stage of development, soon after ovulation. The amount of connective tissue located in the middle of the corpus luteum indicates the age of the organ. Note the huge size of the corpus luteum; it occupies most of the section.<br />
<br />
Observe again that granulosa lutein cells make up the bulk of the corpus luteum; these are large cells with granular cytoplasm, vesicular nuclei and prominent nucleoli. Due to artifact of preparation or postmortem changes the cells are separated from each other by spaces.<br />
<br />
The granulosa lutein cells are arranged into groups separated by delicate strands of connective tissue and capillaries.<br />
<br />
In the central cavity are strands of clotted blood (red blood corpuscles and precipitated fibrin) and fine fibrin filaments. Little or no connective tissue is present as yet.<br />
<br />
Numerous dilated blood vessels are seen in the stroma around the periphery of the corpus luteum, probably still in this state from their preovulatory condition.<br />
<br />
The blue-staining connective tissue on the outer margin of the corpus luteum represents the former theca externa.<br />
<br />
Theca lutein cells are present on the periphery and in the folds of this corpus luteum but are not yet well differentiated, thus are not easily identified. Blood vessels and connective tissue will be growing in from the former theca externa.<br />
<br />
If fertilization does not take place, the corpus luteum persists for about two weeks, and then it breaks down (regresses) to become a corpus albicans. The corpus luteum in this case is called a corpus luteum spurium (false) or corpus luteum of menstruation.<br />
<br />
If fertilization occurs, the corpus luteum persists, gets larger, and lasts longer; it is now called a corpus luteum verum (true) or corpus luteum of pregnancy.<br />
<br />
<peir-vm>UAB-Histology-00254</peir-vm><br />
<br />
== Uterine Tube ==<br />
<br />
Each uterine tube is about 12 cm long and serves to connect the uterus with the ovaries for transport of spermatozoa, fertilization of the ovum and nourishment and transport of the zygote. The uterine tube is embedded in (courses through) the mesosalpinx which is the upper part of the broad ligament of the uterus. Within this mesentery of the uterine tube is a central core of connective tissue, some smooth muscle, blood vessels and nerves, and it is covered by a serosa (peritoneum). Thus the wall of the uterine tube consists of three layers: a mucosa, a muscularis and a serosa.<br />
<br />
Four regions of the uterine tube are generally recognized; from the uterus distally they are the interstitial (intramural) segment, the isthmus, the ampulla and the infundibulum. Only two regions or segments are represented in these slides. These are slides of the ampulla (slides 256, 257 and 258 and of the isthmus (slide 259).<br />
<br />
=== Slide 257, Uterine Tube Ampulla (Masson) ===<br />
<br />
Study the mucosa (mucous membrane) of this section of the uterine tube; note the complex foldings of the mucosa. The epithelium is actually simple columnar, but it frequently appears pseudostratified. It is tallest in the ampulla and decreases in height towards the uterus.<br />
<br />
The epithelium consists of two types of cells, ciliated columnar cells (numerous on the fimbria and in the ampulla) and non-ciliated columnar secretory cells (peg cells).<br />
<br />
The thin lamina propria is a primitive type of connective tissue, quite cellular; it extends into the folds. It is loosely arranged in the ampulla and is quite vascular. (It undergoes a decidual reaction, resembling decidual stromal cells found in the endometrium of the pregnant uterus, when tubal pregnancy occurs).<br />
<br />
Observe the muscularis (muscular coat). It has two ill-defined smooth muscle layers; the inner spiral circular layer is thicker than the outer longitudinal muscle layer. Fine connective tissue intermingles with smooth muscle cells.<br />
<br />
Surrounding the muscularis and intermingling with it is vascular connective tissue of the mesosalpinx. Note here the numerous greatly congested blood vessels of various diameters. Such congestion usually indicates a preovulatory state. A serosa forms the outermost layer.<br />
<br />
<peir-vm>UAB-Histology-00257</peir-vm><br />
<br />
=== Slide 258, Uterine Tube, Ampulla (PASH) ===<br />
<br />
This section of uterine tube is also from the ampulla in a pre-ovulatory state.<br />
<br />
The two epithelial cell types can be identified; there appear to be fewer ciliated cells (may be post-mortem loss). PAS clearly demonstrates basement membranes of the epithelial cells as well as elastic membranes in blood vessels.<br />
<br />
In the lamina propria, the looseness of the connective tissue in the folds is better demonstrated than in slide 257. Note branched fibroblasts and scattered lymphocytes. Lymphocytes may also be seen migrating through the epithelium to be eliminated from the body. Many dilated blood vessels are seen in this region.<br />
<br />
The muscularis appears as patches of smooth muscle fibers dispersed among a loose arrangement of connective tissue fibers. Numerous dilated blood vessels are interspersed in the connective tissue among the bundles of muscle fibers.<br />
<br />
<peir-vm>UAB-Histology-00258</peir-vm><br />
<br />
=== Slide 256, Uterine Tube (Ampulla) of Pregnancy (Masson) ===<br />
<br />
This section represents uterine tube removed from a pregnant woman. There are artifactual breaks in the tissue section. <br />
<br />
Identify the cell types in the epithelium. Nonciliated peg cells are most predominant, but this varies from place to place. The connective tissue of the lamina propria has proliferated to appear more like a primitive connective tissue; lymphocytes are more numerous. In the connective tissue you may be able to see large, pale-staining decidual cells which look like macrophages. These are glycogen storing cells that occur in great numbers in the uterus during pregnancy.<br />
<br />
Lymphocytes, decidual cells, and other cells appear to be working their way between the epithelial cells into the lumen, probably a reaction to an interrupted pregnancy. They are surrounded by a vacuole.<br />
<br />
Identify the layers of smooth muscle forming the muscularis, the numerous blood vessels in the connective tissue between the muscle bundles, and serosa covering most of the section.<br />
<br />
<peir-vm>UAB-Histology-00256</peir-vm><br />
<br />
=== Slide 259, Uterine Tube (Masson) ===<br />
<br />
This section is from the isthmus segment of the uterine tube, which lies along the uterine wall. Compare with slide 257, ampulla.<br />
<br />
Observe the size of the lumen, the degree of mucosal folding, the height of the epithelium and the width of the lamina propria and the muscularis. The mucosal foldings are much less complex than in the ampulla.<br />
<br />
Due to the thickness of this section of uterine tube its epithelium appears to be pseudostratified tall columnar. The nuclei are elongated and a few cells appear ciliated.<br />
<br />
The lamina propria is more compact in the isthmus than in the folds of the ampulla.<br />
<br />
Compare this section with that of the ductus deferens (slide 232) with which it might be confused. One should be able to distinguish them by the epithelium and by the layers of muscle.<br />
<br />
<peir-vm>UAB-Histology-00259</peir-vm><br />
<br />
<br />
== Uterus ==<br />
<br />
The uterine slides demonstrate two phases of the menstrual cycle and one of pregnancy. No slides are available from premenstrual and menstrual phases of the uterus.<br />
<br />
Slide 278 (H&E) is from the early proliferative phase.<br />
<br />
Slide 261 (H&E) is from the proliferative phase.<br />
<br />
Slide 262 (H&E) is from the secretory phase.<br />
<br />
Slide 264 (PASH) is from pregnant uterus; it shows decidual cells in the stroma and also has some placenta attached to it.<br />
<br />
=== Slide 278, Uterus, cross-section (H&E) ===<br />
<br />
Slide 278, Uterus, cross-section (H&E), shows endometrium in early to mid- proliferative phase of the menstrual cycle (days 7 to 9).<br />
<br />
Identify: endometrium (mucosa), myometrium (muscularis), and perimetrium (serosa).<br />
<br />
Study the endometrium.<br />
<br />
Distinguish two zones in the endometrium:<br />
<br />
*The basalis (deep layer) where the stroma is compact and glands are branched.<br />
<br />
*The functionalis, the entire endometrium above this. The stroma is not as compact as in the basal layer, but is quite dense in comparison with endometrium in later phases of the cycle.<br />
<br />
Note the simple columnar surface epithelium; it may appear pseudostratified but all nuclei are similar, therefore all cells are columnar. Occasional lymphocytes lying in a small vacuole are seen in the columnar cells.<br />
<br />
Simple tubular glands indent from the surface epithelium and extend through the thickness of the endometrium, becoming branched in their deepest parts. Some glands may extend into the myometrium for a short distance. The glandular epithelium is simple columnar that may also appear pseudostratified. Cytoplasm is very granular. Nuclei are basally located. Epithelium is proliferating; look for mitotic figures.<br />
<br />
The stroma is a “cellular” connective tissue, with fibroblasts with large oval nuclei and branching cell processes embedded in fine collagenous and reticular fibers. It resembles embryonic connective tissue. Some proliferation of fibroblasts is still in progress; look for mitotic figures. Some lymphocytes are present, especially in the most peripheral stroma. Note that the stroma is denser in the basal layer. This region remains relatively inactive.<br />
<br />
Look for coiled arteries in the lower fourth or third of the endometrium. Later, they will extend almost to the surface. A group of cross sections of these arterioles or very small arteries represents one coiled artery. Capillaries and venules are throughout the endometrium.<br />
<br />
Myometrium (muscularis).<br />
<br />
Note the thickness of the myometrium and the density of the muscle. Attempt to define the three layers of muscle but in a section it is difficult to do so.<br />
<br />
Stratum subvasculare, adjacent to the endometrium. Muscle fibers are in compact bundles, in cross or oblique sections (course longitudinally in the intact uterus), with prominent septa between them.<br />
<br />
Stratum vasculare, the middle layer, the thickest part of the muscularis. Interlacing bundles of muscle course both circularly and spirally.<br />
<br />
Note the large blood vessels in the deeper part of this stratum. Their peculiarities are normal for the uterus. These include muscle in the intima of the arteries, increased muscle in the media of the veins, and sometimes muscle in the adventitia of both. (Some arteries in this slide have arteriosclerosis or intimal hyalinzation.)<br />
<br />
Stratum supravasculare, the thin most peripheral layer, with longitudinal and circular fibers.<br />
<br />
Perimetrium (typical serosa): mesothelium and a little underlying loose connective tissue.<br />
<br />
<peir-vm>UAB-Histology-00278</peir-vm><br />
<br />
=== Slide 261, Uterus (H&E) ===<br />
<br />
Slide 261, Uterus (H&E), later proliferative phase, probably about days 10-12.<br />
<br />
Study the endometrium in comparison with slide 278.<br />
<br />
Note that the endometrium is a wider layer.<br />
<br />
Stroma is much less compact - more tissue fluid is present, fibroblasts are farther apart. Nearer the epithelium, stroma in places is beginning to have a spongy appearance.<br />
<br />
Glandular cells are larger, nuclei are large and vesicular, and epithelium appears pseudostratified. Secretion (glycogen, mucin) is beginning to accumulate at the bases of many cells. Small vacuolated areas represent the secretions that are removed during section preparation.<br />
<br />
Fibroblasts are seen more distinctly in the looser stroma; note their processes. Look for mitoses. Small lymphocytes are scattered throughout.<br />
<br />
Look for coiled arteries but they are not too prominent on this slide. Look for other small blood vessels.<br />
<br />
<peir-vm>UAB-Histology-00261</peir-vm><br />
<br />
=== Slide 262, Uterus (H&E) ===<br />
<br />
Slide 262, Uterus, (H&E) exhibits endometrium in a very late secretory phase or early premenstrual (probably days 24-26 of cycle; it is difficult to date precisely).<br />
<br />
Study the endometrium of this phase of the uterine cycle.<br />
<br />
Compare the width of the endometrium in this phase of the cycle with that in the previous slide.<br />
<br />
Note the characteristic large sacculated glands (“corkscrew appearance”). These are prominent throughout most of the functional zone. In the upper region of the functionalis zone (towards the surface) the glands have larger lumina but the sacculations in the walls are less.<br />
<br />
Note the position of the nuclei and the size of the glandular cells. Secretory material has moved from the infranuclear position to the supranuclear position, and some secretion has been liberated into the lumens of the glands. Therefore, the cells are smaller than in the earlier secretory stages, pseudostratification is much less apparent, and nuclei are basally located.<br />
<br />
Note areas of edema in the functional zone, but much of the excessive tissue fluid has already been resorbed.<br />
<br />
Note now the large size of the coiled arteries and their extent halfway or more upward into the functional zone.<br />
<br />
Observe the increased vascularity of capillaries and venules, especially in the outer functional zone. Some may already have ruptured.<br />
<br />
The surface epithelium is still intact.<br />
<br />
Note the myometrium and its blood vessels. Perimetrium is not present.<br />
<br />
<peir-vm>UAB-Histology-00262</peir-vm><br />
<br />
=== Slide 281, Cervix and OS Cervix, one wall (H&E) ===<br />
<br />
Slide shows endocervical epithelium and glands. The plane of section missed the junctional zone between endocervix and os cervix.<br />
<br />
Locate the os cervix (portio vaginalis) which is lined with stratified squamous epithelium. It can be seen grossly on the right margin of the section.<br />
<br />
Look along either surface of the section for cervical mucosa. The simple columnar lining epithelium consists of tall columnar cells, mucus-secreting; the luminal margin of the cells often appears indistinct or ragged. Note the Nabothian cyst (a cyst of a mucous gland of the cervix).<br />
<br />
The surface epithelium continues down to line the simple branched tubular mucus-secreting cervical glands.<br />
<br />
The lamina propria is no longer a primitive connective tissue as in the uterine endometrium.<br />
<br />
The mucosa is often folded, forming plicae palmatae.<br />
<br />
<peir-vm>UAB-Histology-00281</peir-vm><br />
<br />
== Vagina ==<br />
<br />
The vagina is a thick-walled fibromuscular tube that connects the uterus with the exterior and serves as a cavity for the reception of the penis at coitus and as a birth canal at the time of parturition.<br />
<br />
=== Slide 266, Vagina (H&E) ===<br />
<br />
The wall of the vagina consists of a mucosa, a muscularis, and a broad fibrosa that connects it to adjacent structures. The mucosa is thrown into broad folds (rugae) which are gross structures, not demonstrable in a small piece of tissue used for microscopic slides.<br />
<br />
Mucosa<br />
<br />
The epithelium is non-cornified stratified squamous. Note the stratum basale, the stratum spinosum, and the stratum corneum, so-called even though it is not cornified. The cells that appear empty contain glycogen and mucin, both of which are removed during routine section preparation.<br />
<br />
The broad areas of epithelium are tangential sections. Cross-sections of connective tissue papillae may be seen within them.<br />
<br />
Note connective tissue papillae projecting into the epithelium from the lamina propria. These are characteristic of most stratified squamous epithelia.<br />
<br />
The lamina propria is a broad zone of highly vascularized connective tissue, with abundant elastic fibers, extending to the muscularis. The elastic fibers may be seen as fine homogenous threads. (There is no muscularis mucosae or submucosa.) Note numerous small blood vessels and nerves. In many of the vessels, the endothelial cells (nuclei) are hypertrophied - not a normal condition.<br />
<br />
Scattered lymphocytes and plasma cells are seen throughout the mucosa. Lymphocytes may aggregate just below the epithelium to form diffuse lymphatic tissue or an occasional small nodule. Lymphocytes may penetrate the epithelium to migrate toward its surface.<br />
<br />
The muscularis, mostly arranged longitudinally, appears as bundles of smooth muscle interspersed with connective tissue rich in elastic fibers which may be seen as thin, homogenous threads. Larger blood vessels, as well as small ones, are found in the deep muscularis or fibrosa.<br />
<br />
The fibrosa is loose connective tissue. It should have some adipose tissue and nerves.<br />
<br />
<peir-vm>UAB-Histology-00266</peir-vm><br />
<br />
=== Slide 265, Vagina (Masson) ===<br />
<br />
Identify the regions of the wall and their component parts as in slide 266.<br />
<br />
Muscle and connective tissue are easily differentiated with Masson’s; they stain red and blue respectively. All nuclei stain red, as do erythrocytes. Elastic fibers are not distinguishable.<br />
<br />
The vascularity of the lamina propria is emphasized, with many of the venules congested.<br />
<br />
The large amount of connective tissue between the muscle bundles is well demonstrated.<br />
<br />
Lightly staining nerves occur among the muscle bundles and in the fibrosa.<br />
<br />
<peir-vm>UAB-Histology-00265</peir-vm><br />
<br />
== Placenta and Umbilical Cord ==<br />
<br />
Slides: 275, 264, 273, 274, 279, 280.<br />
<br />
=== Slide 275, Chorionic Villi (H&E) ===<br />
<br />
This is a section of a small part of a fetal placenta of a very early pregnancy, showing chorionic villi and the surrounding maternal blood spaces. Some slides have a strip of chorionic plate across the upper margin of the section.<br />
<br />
Chorionic plate<br />
<br />
The greater part of the plate is chorion, composed of a mass of embryonic connective tissue (large fibroblasts, fine collagenous fibers, abundant ground substance), covered on its lower surface by a double layer of epithelial cells: the cytotrophoblast adjacent to the connective tissue, and the syntrophoblast (syncytial trophoblast) on the free surface, bordering on maternal blood spaces.<br />
<br />
Cells of the syntrophoblast do not show cell boundaries. Ragged cell surfaces indicate microvilli. Cells of the cytotrophoblast supposedly show cell boundaries but they are not readily seen here. They divide to form syntrophoblast.<br />
<br />
Note blood vessels in the connective tissue (branches of umbilical vessels) containing nucleated fetal red blood corpuscles.<br />
<br />
The small zone of looser connective tissue in the upper part of the chorionic plate is part of the amnion. The cuboidal surface epithelium has been torn off.<br />
<br />
Chorionic villi. The villi are outgrowths from the chorion, having the same structure as the chorion. They increase in size and branch repeatedly as they invade the maternal blood spaces. The initial larger villi will become the anchoring villi that will penetrate the endometrium (decidua basalis) to anchor the fetal placenta. Smaller villi sprout off the anchoring villi.<br />
<br />
Note that the villi vary in size. The largest ones are potential anchoring villi. Others are floating villi; their free ends are in the blood spaces.<br />
<br />
Each villus has a core of embryonic connective tissue, branches of umbilical vessels (sparse in this early placenta), and a covering of inner cytotrophoblast and superficial syntrophoblast.<br />
<br />
<peir-vm>UAB-Histology-00275</peir-vm><br />
<br />
=== Slide 264, Uterus and Placenta from a later stage of pregnancy (PASH) === <br />
<br />
Look at the fetal placenta.<br />
<br />
Villi are larger and more numerous than in slide 275, stroma is generally more compact with more collagenous fibers (still fine) and abundant fibroblasts.<br />
<br />
Blood vessels in the villi are more numerous. Capillaries and little venules are peripherally located close to the trophoblast cells, although this may not be obvious due to plane of sections. Note that now red blood corpuscles are not nucleated.<br />
<br />
Syntrophoblast and cytotrophoblast are still present but cytotrophoblast is incomplete in many areas. (It will disappear entirely by late pregnancy.)<br />
<br />
Look for macrophages (Hofbauer cells) in the stroma of the villi - large rounded cells whose cytoplasm may have small vacuoles and/or PAS positive granules.<br />
<br />
Look for syncytial knots on the surface of villi or in the intervillous spaces. These are groups of syntrophoblast cells that detach from the villi and float freely in the spaces; progressively more are formed toward term.<br />
<br />
Look for very small deposits of fibrinoid, on or in the villi or in the intervillous spaces, a non-cellular, homogenous, proteinaceous material associated with transplantation immunity to protect the fetus.<br />
<br />
Maternal placenta (decidua basalis) and uterus. The decidua basalis is the name given to the endometrium that underlies the villi of the fetal placenta. Some villi (anchoring villi) penetrate the decidua basalis (endometrium) for varying distances. In doing so, part of the surface of the endometrium has been eroded and destroyed (surface epithelium is missing).<br />
<br />
Look for anchoring villi attaching to the decidua basalis. Note larger fibrinoid deposits and aggregations of syncytial knots in this region.<br />
<br />
In the decidua basalis, note the vast numbers of large and smaller decidual cells with PAS- positive cytoplasm (are storing glycogen) and large, lightly staining nuclei. Cytoplasm of those with less glycogen stains faintly acidophilic or somewhat grayish. Decidual cells are derived from fibroblasts of the endometrium.<br />
<br />
A few glands are seen in the basal zone of the endometrium. They may be dilated, have very low epithelium or hypertrophied epithelium, and have lymphocytic infiltration surrounding some of them.<br />
<br />
Identify the myometrium and note the large size of the muscle fibers that hypertrophy greatly during pregnancy.<br />
<br />
<peir-vm>UAB-Histology-00264</peir-vm><br />
<br />
=== Slide 280. Uterus and Placenta near term (H&E) ===<br />
<br />
Fetal placenta. Proliferation of villi has continued to increase during pregnancy.<br />
<br />
Note the great number of chorionic villi, practically filling the maternal blood spaces. The anchoring villi have become very large. The connective tissue in the core is fibrous, but embryonic connective tissue has persisted at the periphery. The larger blood vessels course in these villi. Observe the variation in size of the floating villi, which continue to form throughout pregnancy.<br />
<br />
In the villi, note further compactness of stroma, areas of more dense collagenous fibers, more capillaries, and venules close to the trophoblast.<br />
<br />
Look for macrophages (Hofbauer cells) in the stroma of the villi. With H&E, the cytoplasm is finely vacuolated.<br />
<br />
Syntrophoblasts still cover the surface of the villi. Cytotrophoblasts have generally disappeared.<br />
<br />
Note increased number of syncytial knots and much fibrinoid material. Knots are seen deep in the endometrium; they appear as darkly stained groups of pyknotic nuclei.<br />
<br />
The maternal placenta (decidua basalis).<br />
<br />
Again note the placental villi anchoring into the endometrium.<br />
<br />
Decidual cells are still present in the endometrium but many have “used up” their glycogen and are reverting to fibroblasts. Lymphocytic infiltration is seen in places. Much fibrinoid is present.<br />
<br />
Uterine glands, whose basal portions had remained inactive, are proliferating and regenerating. Some appear cystic.<br />
<br />
Uterine Muscularis.<br />
<br />
The three layers are not readily identified, but note again the large size of the fibers.<br />
<br />
Note the huge multinucleated giant cells in the deep endometrium and especially in the muscularis. They are thought to be of trophoblastic origin (perhaps differentiated from but not to be confused with syncytial knots).<br />
<br />
<peir-vm>UAB-Histology-00280</peir-vm><br />
<br />
=== Slide 279. Placenta at term (H&E) ===<br />
<br />
These slides are from a “fresh” placenta immediately after parturition; thus very little postmortem change is present and structures are seen distinctly.<br />
<br />
Go over the fetal placenta as in slide 280. Numerous red blood corpuscles are present in the maternal blood spaces, probably due to rupture of blood vessels during parturition.<br />
<br />
Note the tremendous vascularity of the placental villi, apparent here because of the fresh condition of the tissues; note also the great number of syncytial knots.<br />
<br />
A fragment of decidua basalis may be present (left end of the section in the field). Anchoring villi are seen and large decidual cells may still be present.<br />
<br />
<peir-vm>UAB-Histology-00279</peir-vm><br />
<br />
=== Slide 274, Placenta at term (PASH) ===<br />
<br />
This tissue is from the same placenta used for making slides 279 and 273. Look at the slide to see how term structures stain with PASH.<br />
<br />
Basement membranes are prominent under the syntrophoblast and under endothelium of the blood vessels. Note also that blood vessels are more numerous in these villi than in those of slide 280, are also congested which may be the cause of their large size.<br />
<br />
Areas of decidua basalis are present.<br />
<br />
<peir-vm>UAB-Histology-00274</peir-vm><br />
<br />
=== Slide 273, Placenta, term (Masson) ===<br />
<br />
This tissue is from the same placenta as used for making slides 274 and 279.<br />
<br />
Identify the structures as seen with this stain. Connective tissue elements are blue, nuclei are reddish or indistinct, and the cytoplasm varies. <br />
<br />
This section shows the chorionic plate at the right (in the field).<br />
<br />
The outer “membrane” is the amnion, consisting of a layer of cuboidal or low columnar epithelium and a thin layer of connective tissue. It is mechanically separated from the underlying chorion.<br />
<br />
The chorion consists of a layer of connective tissue covered by syncytial trophoblast that is now mostly fibrinoid.<br />
<br />
Two main umbilical vessels and smaller branches are passing through the chorionic plate.<br />
<br />
<peir-vm>UAB-Histology-00273</peir-vm><br />
<br />
== Umbilical Cord ==<br />
<br />
=== Slide 287, Umbilical Cords (H&E) ===<br />
<br />
Slide 287, Umbilical Cords (H&E), is from an early pregnancy and from late in pregnancy.<br />
<br />
The early pregnancy umbilical cord is on the left. The two umbilical arteries and the umbilical vein look generally similar because of the atypical large amount of muscle in the wall. An internal elastic membrane is lacking in the arteries. The diameter of the vein is greater than that of the artery and the muscle is not quite as compactly arranged.<br />
<br />
The stroma of the cord is mucous connective tissue - embryonic connective tissue with a mucoid ground substance (Wharton’s jelly) which is removed in section preparation. Note the fine collagenous fibers and the large branched fibroblasts.<br />
<br />
Covering the cord is simple squamous or simple cuboidal epithelium, part of the amnion.<br />
<br />
<peir-vm>UAB-Histology-00287</peir-vm><br />
<br />
=== Slides 287 (tissue on right) and Slide 277, umbilical cord at term (H&E) ===<br />
<br />
In this fully developed placenta, the atypical structure of the arteries is well shown - a wide inner layer of longitudinally arranged muscle and a thick outer circular layer. Postmortem contraction causes collapse of the vessels. The vein has some inner longitudinal muscle; most of it is outer circular. Reticular fibers between muscle fibers are seen with H&E (due to postmortem shrinkage of muscle fibers). The small vacuoles are probably early degenerative changes.<br />
<br />
Collagenous fibers in the stroma are somewhat heavier than in the earlier cord but are not mature fibers. Mucous connective tissue retains its embryonic nature; note that fibroblasts are still large branched cells.<br />
<br />
Neutrophils are invading some areas of the stroma (lower field especially), also related to breakdown of the tissues.<br />
<br />
Epithelium of the amnion surrounds the cord.<br />
<br />
==== Slide 287, Umbilical Cord at term (tissue on right) (H&E) ====<br />
<peir-vm>UAB-Histology-00287</peir-vm><br />
==== Slide 277, Umbilical Cord at term (H&E) ====<br />
<peir-vm>UAB-Histology-00277</peir-vm><br />
<br />
{{Template:Histologic}}<br />
<br />
[[Category:Histologic]]</div>Matthew Andersonhttps://peir.path.uab.edu/index.php?title=File:HistologicChapter17Ovary.jpg&diff=3256File:HistologicChapter17Ovary.jpg2014-07-21T19:31:23Z<p>Matthew Anderson: </p>
<hr />
<div></div>Matthew Andersonhttps://peir.path.uab.edu/index.php?title=Histologic:Chapter_17&diff=3255Histologic:Chapter 172014-07-21T19:29:23Z<p>Matthew Anderson: /* Placenta And Umbilical Cord */</p>
<hr />
<div>== Introduction ==<br />
<br />
The female reproductive system consists of the ovaries, the two uterine tubes (oviducts or Fallopian tubes) a uterus, a vagina, the external genitalia and the mammary glands. Normally, the development of this system requires that the zygote have the XX sex chromosomal complement. The ovaries produce the ova or female germ cells and certain hormones; the uterine tubes are necessary for transporting sperm to the ova for fertilization and for transporting the zygote to the uterus. Growth and maturation of the conceptus occur in the uterus. The vagina and external genitalia are the copulatory organs and the mammary glands serve for nutrition of the newborn.<br />
<br />
== Ovary ==<br />
<br />
With the exception of slide 255, Monkey ovary (PASH), all other slides were obtained from human sources.<br />
<br />
Study first slide 255 since it shows all the representative stages of follicle development. Then study slide 251, Ovary, (H&E); it has very small normal follicles, larger atretic follicles and corpora albicantia. Slide 254 Ovary (Masson) shows a large well-developed corpus luteum and a small atretic follicle with a prominent glassy membrane.<br />
<br />
=== Slide 255, Ovary (PASH) ===<br />
<br />
Slide 255, Ovary (PASH) shows a mature ovary with one large corpus luteum, several large preovulatory follicles, smaller growing follicles, and atretic follicles. Only a portion of the whole ovary is on the slide. <br />
<br />
Study the cortex of the ovary.<br />
<br />
Identify the surface epithelium (germinal epithelium), the tunica albuginea (a zone immediately beneath the surface epithelium which is more compact and less cellular than the stroma) and the stroma of cellular connective tissue.<br />
<br />
Study the various stages of follicles.<br />
<br />
Primordial (unilaminar follicles) consists of a small primary oocyte surrounded by a single layer of squamous follicular cells which rest on a basement membrane.<br />
<br />
A primary follicle contains an enlarging oocyte surrounded by a single layer of flattened, cuboidal or low columnar follicular cells. These cells give rise to granulosa cells by mitosis.<br />
<br />
Growing or multilaminar follicles are surrounded by several layers of follicular cells.<br />
<br />
Vesicular (secondary or antral) follicles consist of a primary oocyte surrounded by 6-12 layers of granulosa cells. Fluid-filled spaces that appear between the granulosa cells gradually enlarge, interconnect, and eventually form a crescent-shaped cavity, the antrum.<br />
<br />
Note the PAS-positive staining basement membrane located between the outer row of granulosa cells of the follicle and the stromal cells. Observe that the stromal cells are organized as a sheath of cells around the growing follicles.<br />
<br />
The vesicular follicles are surrounded by a stromal sheath called the theca folliculi; the theca is divided into two regions, a theca interna and a theca externa.<br />
<br />
The theca interna is a zone of epithelioid stromal cells surrounding the outer granulosa cells but separated from them by the basement membrane; this portion of the theca is vascular, containing capillaries and smaller blood vessels.<br />
<br />
The theca externa lies external to the theca interna and consists of condensed stroma.<br />
<br />
As the follicle enlarges, so does the oocyte. Increase in volume of both the nucleus and the cytoplasm accounts for oocyte enlargement. Observe the prominent nucleolus and the nuclear membrane of the oocytes; note that the cytoplasm is weakly acidophilic.<br />
<br />
The zone pellucida is a prominent PAS-positive staining membrane immediately surrounding the oocyte’s plasma membrane. It is not present in primordial follicles or in smaller growing follicles.<br />
<br />
The degeneration of follicles is called atresia and signs of this activity can be identified as follows:<br />
<br />
*The granulosa cell layer may be partially detached from the theca interna.<br />
*Groups of cells with pyknotic nuclei appear in the granulosa layer. <br />
*Fragmentation of the oocytes may be occurring.<br />
*The oocyte nucleus may be pyknotic (highly condensed and dark staining).<br />
*The basement membrane is very irregular, wavy, and fragmented. <br />
*The zone pellucida is fragmented or broken in places.<br />
<br />
Study the vesicular (secondary or antral) follicles.<br />
<br />
Identify early antrum formation in which the follicular cavity is small. Call-Exner bodies may be present between granulosal cells; they are strongly PAS-positive.<br />
<br />
Find a large follicle (large antrum) in which the large volume of the antrum indicates it is filled with fluid called liquor folliculi.<br />
<br />
The cumulus oophorus is a mound or hill of granulosa cells surrounding and supporting the large oocyte. This structure is present in the mature (Graafian) follicle.<br />
<br />
The corona radiata is a cluster of granulosal cells which immediately surrounds the zona pellucida. When the ovum breaks free from the cumulus oophorus the corona radiata cells “go with it” and surround the ovum during ovulation and transport into the uterine tube.<br />
<br />
Recall that just prior to ovulation, the primary oocyte undergoes its first maturation division, giving off the first polar body, to form a secondary oocyte. The final maturation division will not occur unless fertilization ensues.<br />
<br />
Study the corpus luteum.<br />
<br />
A corpus luteum is a new endocrine organ that makes its appearance after ovulation. The granulosa cells of the follicle hypertrophy, become luteinized and form granulosa lutein cells which secrete primarily progesterone. The corpus luteum on this slide is in an early stage of development. Note its large size. It consists of a thick folded wall and a central cavity (the former antrum of the follicle) which is filling in which fibrin deposits and loose connective tissue growing in from the theca externa. <br />
<br />
Most of the wall is composed of granulosa lutein cells derived from the granulosa cells of the mature follicle. They are large cells with pale cytoplasm and a vesicular nucleus containing a prominent nucleolus. The cell membrane is stained with PAS. The cells are packed closely together, but fibroblasts, fine connective tissue, and capillaries invading from the stroma are penetrating between the cells toward the central cavity.<br />
<br />
The theca lutein cells form a thin zone at the periphery of the corpus luteum and extend into the folds (which were formed when the ruptured follicle collapsed). They are not too apparent with this stain, but they are smaller cells than granulosa lutein cells.<br />
<br />
The former antrum has fibrin deposits and is filling in with loose connective tissue.<br />
<br />
The remains of atretic follicles can be seen as small irregular, intensely stained PAS-positive structures that are hypertrophied zona pellucida remnants from atretic follicles. They may or may not be surrounded by a greatly thickened folded glassy membrane (basement membrane) which stains pink. Both structures will be replaced by stroma.<br />
<br />
<br />
Study the medulla of the ovary.<br />
<br />
The medulla contains fibroelastic tissue, many large and smaller vessels, nerves, and lymphatics. Most of the blood vessels are highly coiled or convoluted.<br />
<br />
The medulla is continuous with the connective tissue of the mesovarium, a short peritoneal fold that attaches the ovary to the broad ligament; the point of attachment serves as a hilus for the ovary. The mesothelium of the serosa (visceral peritoneum) of the mesovarium is continuous with the surface epithelium of the ovary.<br />
<br />
A homologue to the rete testis in the male, the rete ovarii, can be seen in one part of the medulla (upper left in the field). They are distinguished by small, deeply basophilic nuclei of cuboidal cells lining an irregular-shaped lumen.<br />
<br />
<peir-vm>UAB-Histology-00255</peir-vm><br />
<br />
<br />
=== Slide 251, Ovary, Human (H&E) (From an elderly woman) === <br />
<br />
Study the cortex of this ovary.<br />
<br />
Note the prominent tunica albuginea just underneath the surface epithelium. The single layer of simple cuboidal cells making up the surface epithelium is present only in patches since part of it was sloughed off during preparation of the tissue.<br />
<br />
The stroma is much more evident on this slide as compared with the monkey ovary just studied. Note the swirling pattern of the stromal cells, especially how they begin to swirl and encircle a follicle some distance from the follicle. In growing follicles, the stromal cells begin to condense into the thecal follicular sheath of cells that contribute to the function of the follicle.<br />
<br />
Find primordial, primary and small growing follicles; (Primordial follicles are rare in mature ovaries). Note those follicles that show signs of atresia.<br />
<br />
The two or three large follicles (preovulatory follicles) on this slide are also in early atresia. Granulosa cells have sloughed off or are still sloughing; the basement membrane in one follicle is beginning to hypertrophy.<br />
<br />
Look for parts of corpora albicantia (singular = corpus albicans) which are fibrous scars that replace regressed corpora lutea; they are composed of compact collagenous fibers and fibroblasts, and have indefinite borders which merge with the stroma<br />
<br />
Study the medulla of this ovary. <br />
<br />
Note numerous, prominent blood vessels of various caliber which take up most of the volume of the medulla. Some of these vessels are quite convoluted (a long row of cross-sections of a vessel, each cross-section of about the same diameter, may be observed.<br />
<br />
Lymphatics are also a prominent feature of the ovarian medulla. They are more difficult to distinguish because their thin walls may have collapsed, eliminating the lumen.<br />
<br />
Vasomotor nerves to the smooth muscles of blood vessels may be seen; they are too small to see clearly.<br />
<br />
<peir-vm>UAB-Histology-00251</peir-vm><br />
<br />
<br />
=== Slide 254, Ovary, Human (Masson) ===<br />
<br />
The principal structure occupying most of this section is a corpus luteum. Other follicles may also be present, but concentrate on the corpus luteum.<br />
<br />
The corpus luteum represents a very young stage of development, soon after ovulation. The amount of connective tissue located in the middle of the corpus luteum indicates the age of the organ. Note the huge size of the corpus luteum; it occupies most of the section.<br />
<br />
Observe again that granulosa lutein cells make up the bulk of the corpus luteum; these are large cells with granular cytoplasm, vesicular nuclei and prominent nucleoli. Due to artifact of preparation or postmortem changes the cells are separated from each other by spaces.<br />
<br />
The granulosa lutein cells are arranged into groups separated by delicate strands of connective tissue and capillaries.<br />
<br />
In the central cavity are strands of clotted blood (red blood corpuscles and precipitated fibrin) and fine fibrin filaments. Little or no connective tissue is present as yet.<br />
<br />
Numerous dilated blood vessels are seen in the stroma around the periphery of the corpus luteum, probably still in this state from their preovulatory condition.<br />
<br />
The blue-staining connective tissue on the outer margin of the corpus luteum represents the former theca externa.<br />
<br />
Theca lutein cells are present on the periphery and in the folds of this corpus luteum but are not yet well differentiated, thus are not easily identified. Blood vessels and connective tissue will be growing in from the former theca externa.<br />
<br />
If fertilization does not take place, the corpus luteum persists for about two weeks, and then it breaks down (regresses) to become a corpus albicans. The corpus luteum in this case is called a corpus luteum spurium (false) or corpus luteum of menstruation.<br />
<br />
If fertilization occurs, the corpus luteum persists, gets larger, and lasts longer; it is now called a corpus luteum verum (true) or corpus luteum of pregnancy.<br />
<br />
<peir-vm>UAB-Histology-00254</peir-vm><br />
<br />
<br />
== Uterine Tube ==<br />
<br />
Each uterine tube is about 12 cm long and serves to connect the uterus with the ovaries for transport of spermatozoa, fertilization of the ovum and nourishment and transport of the zygote. The uterine tube is embedded in (courses through) the mesosalpinx which is the upper part of the broad ligament of the uterus. Within this mesentery of the uterine tube is a central core of connective tissue, some smooth muscle, blood vessels and nerves, and it is covered by a serosa (peritoneum). Thus the wall of the uterine tube consists of three layers: a mucosa, a muscularis and a serosa.<br />
<br />
Four regions of the uterine tube are generally recognized; from the uterus distally they are the interstitial (intramural) segment, the isthmus, the ampulla and the infundibulum. Only two regions or segments are represented in these slides. These are slides of the ampulla (slides 256, 257 and 258 and of the isthmus (slide 259).<br />
<br />
=== Slide 257, Uterine Tube Ampulla (Masson) ===<br />
<br />
Study the mucosa (mucous membrane) of this section of the uterine tube; note the complex foldings of the mucosa. The epithelium is actually simple columnar, but it frequently appears pseudostratified. It is tallest in the ampulla and decreases in height towards the uterus.<br />
<br />
The epithelium consists of two types of cells, ciliated columnar cells (numerous on the fimbria and in the ampulla) and non-ciliated columnar secretory cells (peg cells).<br />
<br />
The thin lamina propria is a primitive type of connective tissue, quite cellular; it extends into the folds. It is loosely arranged in the ampulla and is quite vascular. (It undergoes a decidual reaction, resembling decidual stromal cells found in the endometrium of the pregnant uterus, when tubal pregnancy occurs).<br />
<br />
Observe the muscularis (muscular coat). It has two ill-defined smooth muscle layers; the inner spiral circular layer is thicker than the outer longitudinal muscle layer. Fine connective tissue intermingles with smooth muscle cells.<br />
<br />
Surrounding the muscularis and intermingling with it is vascular connective tissue of the mesosalpinx. Note here the numerous greatly congested blood vessels of various diameters. Such congestion usually indicates a preovulatory state. A serosa forms the outermost layer.<br />
<br />
<peir-vm>UAB-Histology-00257</peir-vm><br />
<br />
=== Slide 258, Uterine Tube, Ampulla (PASH) ===<br />
<br />
This section of uterine tube is also from the ampulla in a pre-ovulatory state.<br />
<br />
The two epithelial cell types can be identified; there appear to be fewer ciliated cells (may be post-mortem loss). PAS clearly demonstrates basement membranes of the epithelial cells as well as elastic membranes in blood vessels.<br />
<br />
In the lamina propria, the looseness of the connective tissue in the folds is better demonstrated than in slide 257. Note branched fibroblasts and scattered lymphocytes. Lymphocytes may also be seen migrating through the epithelium to be eliminated from the body. Many dilated blood vessels are seen in this region.<br />
<br />
The muscularis appears as patches of smooth muscle fibers dispersed among a loose arrangement of connective tissue fibers. Numerous dilated blood vessels are interspersed in the connective tissue among the bundles of muscle fibers.<br />
<br />
<peir-vm>UAB-Histology-00258</peir-vm><br />
<br />
=== Slide 256, Uterine Tube (Ampulla) of Pregnancy (Masson) ===<br />
<br />
This section represents uterine tube removed from a pregnant woman. There are artifactual breaks in the tissue section. <br />
<br />
Identify the cell types in the epithelium. Nonciliated peg cells are most predominant, but this varies from place to place. The connective tissue of the lamina propria has proliferated to appear more like a primitive connective tissue; lymphocytes are more numerous. In the connective tissue you may be able to see large, pale-staining decidual cells which look like macrophages. These are glycogen storing cells that occur in great numbers in the uterus during pregnancy.<br />
<br />
Lymphocytes, decidual cells, and other cells appear to be working their way between the epithelial cells into the lumen, probably a reaction to an interrupted pregnancy. They are surrounded by a vacuole.<br />
<br />
Identify the layers of smooth muscle forming the muscularis, the numerous blood vessels in the connective tissue between the muscle bundles, and serosa covering most of the section.<br />
<br />
<peir-vm>UAB-Histology-00256</peir-vm><br />
<br />
=== Slide 259, Uterine Tube (Masson) ===<br />
<br />
This section is from the isthmus segment of the uterine tube, which lies along the uterine wall. Compare with slide 257, ampulla.<br />
<br />
Observe the size of the lumen, the degree of mucosal folding, the height of the epithelium and the width of the lamina propria and the muscularis. The mucosal foldings are much less complex than in the ampulla.<br />
<br />
Due to the thickness of this section of uterine tube its epithelium appears to be pseudostratified tall columnar. The nuclei are elongated and a few cells appear ciliated.<br />
<br />
The lamina propria is more compact in the isthmus than in the folds of the ampulla.<br />
<br />
Compare this section with that of the ductus deferens (slide 232) with which it might be confused. One should be able to distinguish them by the epithelium and by the layers of muscle.<br />
<br />
<peir-vm>UAB-Histology-00259</peir-vm><br />
<br />
<br />
== Uterus ==<br />
<br />
The uterine slides demonstrate two phases of the menstrual cycle and one of pregnancy. No slides are available from premenstrual and menstrual phases of the uterus.<br />
<br />
Slide 278 (H&E) is from the early proliferative phase.<br />
<br />
Slide 261 (H&E) is from the proliferative phase.<br />
<br />
Slide 262 (H&E) is from the secretory phase.<br />
<br />
Slide 264 (PASH) is from pregnant uterus; it shows decidual cells in the stroma and also has some placenta attached to it.<br />
<br />
=== Slide 278, Uterus, cross-section (H&E) ===<br />
<br />
Slide 278, Uterus, cross-section (H&E), shows endometrium in early to mid- proliferative phase of the menstrual cycle (days 7 to 9).<br />
<br />
Identify: endometrium (mucosa), myometrium (muscularis), and perimetrium (serosa).<br />
<br />
Study the endometrium.<br />
<br />
Distinguish two zones in the endometrium:<br />
<br />
*The basalis (deep layer) where the stroma is compact and glands are branched.<br />
<br />
*The functionalis, the entire endometrium above this. The stroma is not as compact as in the basal layer, but is quite dense in comparison with endometrium in later phases of the cycle.<br />
<br />
Note the simple columnar surface epithelium; it may appear pseudostratified but all nuclei are similar, therefore all cells are columnar. Occasional lymphocytes lying in a small vacuole are seen in the columnar cells.<br />
<br />
Simple tubular glands indent from the surface epithelium and extend through the thickness of the endometrium, becoming branched in their deepest parts. Some glands may extend into the myometrium for a short distance. The glandular epithelium is simple columnar that may also appear pseudostratified. Cytoplasm is very granular. Nuclei are basally located. Epithelium is proliferating; look for mitotic figures.<br />
<br />
The stroma is a “cellular” connective tissue, with fibroblasts with large oval nuclei and branching cell processes embedded in fine collagenous and reticular fibers. It resembles embryonic connective tissue. Some proliferation of fibroblasts is still in progress; look for mitotic figures. Some lymphocytes are present, especially in the most peripheral stroma. Note that the stroma is denser in the basal layer. This region remains relatively inactive.<br />
<br />
Look for coiled arteries in the lower fourth or third of the endometrium. Later, they will extend almost to the surface. A group of cross sections of these arterioles or very small arteries represents one coiled artery. Capillaries and venules are throughout the endometrium.<br />
<br />
Myometrium (muscularis).<br />
<br />
Note the thickness of the myometrium and the density of the muscle. Attempt to define the three layers of muscle but in a section it is difficult to do so.<br />
<br />
Stratum subvasculare, adjacent to the endometrium. Muscle fibers are in compact bundles, in cross or oblique sections (course longitudinally in the intact uterus), with prominent septa between them.<br />
<br />
Stratum vasculare, the middle layer, the thickest part of the muscularis. Interlacing bundles of muscle course both circularly and spirally.<br />
<br />
Note the large blood vessels in the deeper part of this stratum. Their peculiarities are normal for the uterus. These include muscle in the intima of the arteries, increased muscle in the media of the veins, and sometimes muscle in the adventitia of both. (Some arteries in this slide have arteriosclerosis or intimal hyalinzation.)<br />
<br />
Stratum supravasculare, the thin most peripheral layer, with longitudinal and circular fibers.<br />
<br />
Perimetrium (typical serosa): mesothelium and a little underlying loose connective tissue.<br />
<br />
<peir-vm>UAB-Histology-00278</peir-vm><br />
<br />
=== Slide 261, Uterus (H&E) ===<br />
<br />
Slide 261, Uterus (H&E), later proliferative phase, probably about days 10-12.<br />
<br />
Study the endometrium in comparison with slide 278.<br />
<br />
Note that the endometrium is a wider layer.<br />
<br />
Stroma is much less compact - more tissue fluid is present, fibroblasts are farther apart. Nearer the epithelium, stroma in places is beginning to have a spongy appearance.<br />
<br />
Glandular cells are larger, nuclei are large and vesicular, and epithelium appears pseudostratified. Secretion (glycogen, mucin) is beginning to accumulate at the bases of many cells. Small vacuolated areas represent the secretions that are removed during section preparation.<br />
<br />
Fibroblasts are seen more distinctly in the looser stroma; note their processes. Look for mitoses. Small lymphocytes are scattered throughout.<br />
<br />
Look for coiled arteries but they are not too prominent on this slide. Look for other small blood vessels.<br />
<br />
<peir-vm>UAB-Histology-00261</peir-vm><br />
<br />
=== Slide 262, Uterus (H&E) ===<br />
<br />
Slide 262, Uterus, (H&E) exhibits endometrium in a very late secretory phase or early premenstrual (probably days 24-26 of cycle; it is difficult to date precisely).<br />
<br />
Study the endometrium of this phase of the uterine cycle.<br />
<br />
Compare the width of the endometrium in this phase of the cycle with that in the previous slide.<br />
<br />
Note the characteristic large sacculated glands (“corkscrew appearance”). These are prominent throughout most of the functional zone. In the upper region of the functionalis zone (towards the surface) the glands have larger lumina but the sacculations in the walls are less.<br />
<br />
Note the position of the nuclei and the size of the glandular cells. Secretory material has moved from the infranuclear position to the supranuclear position, and some secretion has been liberated into the lumens of the glands. Therefore, the cells are smaller than in the earlier secretory stages, pseudostratification is much less apparent, and nuclei are basally located.<br />
<br />
Note areas of edema in the functional zone, but much of the excessive tissue fluid has already been resorbed.<br />
<br />
Note now the large size of the coiled arteries and their extent halfway or more upward into the functional zone.<br />
<br />
Observe the increased vascularity of capillaries and venules, especially in the outer functional zone. Some may already have ruptured.<br />
<br />
The surface epithelium is still intact.<br />
<br />
Note the myometrium and its blood vessels. Perimetrium is not present.<br />
<br />
<peir-vm>UAB-Histology-00262</peir-vm><br />
<br />
=== Slide 281, Cervix and OS Cervix, one wall (H&E) ===<br />
<br />
Slide shows endocervical epithelium and glands. The plane of section missed the junctional zone between endocervix and os cervix.<br />
<br />
Locate the os cervix (portio vaginalis) which is lined with stratified squamous epithelium. It can be seen grossly on the right margin of the section.<br />
<br />
Look along either surface of the section for cervical mucosa. The simple columnar lining epithelium consists of tall columnar cells, mucus-secreting; the luminal margin of the cells often appears indistinct or ragged. Note the Nabothian cyst (a cyst of a mucous gland of the cervix).<br />
<br />
The surface epithelium continues down to line the simple branched tubular mucus-secreting cervical glands.<br />
<br />
The lamina propria is no longer a primitive connective tissue as in the uterine endometrium.<br />
<br />
The mucosa is often folded, forming plicae palmatae.<br />
<br />
<peir-vm>UAB-Histology-00281</peir-vm><br />
<br />
== Vagina ==<br />
<br />
The vagina is a thick-walled fibromuscular tube that connects the uterus with the exterior and serves as a cavity for the reception of the penis at coitus and as a birth canal at the time of parturition.<br />
<br />
=== Slide 266, Vagina (H&E) ===<br />
<br />
The wall of the vagina consists of a mucosa, a muscularis, and a broad fibrosa that connects it to adjacent structures. The mucosa is thrown into broad folds (rugae) which are gross structures, not demonstrable in a small piece of tissue used for microscopic slides.<br />
<br />
Mucosa<br />
<br />
The epithelium is non-cornified stratified squamous. Note the stratum basale, the stratum spinosum, and the stratum corneum, so-called even though it is not cornified. The cells that appear empty contain glycogen and mucin, both of which are removed during routine section preparation.<br />
<br />
The broad areas of epithelium are tangential sections. Cross-sections of connective tissue papillae may be seen within them.<br />
<br />
Note connective tissue papillae projecting into the epithelium from the lamina propria. These are characteristic of most stratified squamous epithelia.<br />
<br />
The lamina propria is a broad zone of highly vascularized connective tissue, with abundant elastic fibers, extending to the muscularis. The elastic fibers may be seen as fine homogenous threads. (There is no muscularis mucosae or submucosa.) Note numerous small blood vessels and nerves. In many of the vessels, the endothelial cells (nuclei) are hypertrophied - not a normal condition.<br />
<br />
Scattered lymphocytes and plasma cells are seen throughout the mucosa. Lymphocytes may aggregate just below the epithelium to form diffuse lymphatic tissue or an occasional small nodule. Lymphocytes may penetrate the epithelium to migrate toward its surface.<br />
<br />
The muscularis, mostly arranged longitudinally, appears as bundles of smooth muscle interspersed with connective tissue rich in elastic fibers which may be seen as thin, homogenous threads. Larger blood vessels, as well as small ones, are found in the deep muscularis or fibrosa.<br />
<br />
The fibrosa is loose connective tissue. It should have some adipose tissue and nerves.<br />
<br />
<peir-vm>UAB-Histology-00266</peir-vm><br />
<br />
=== Slide 265, Vagina (Masson) ===<br />
<br />
Identify the regions of the wall and their component parts as in slide 266.<br />
<br />
Muscle and connective tissue are easily differentiated with Masson’s; they stain red and blue respectively. All nuclei stain red, as do erythrocytes. Elastic fibers are not distinguishable.<br />
<br />
The vascularity of the lamina propria is emphasized, with many of the venules congested.<br />
<br />
The large amount of connective tissue between the muscle bundles is well demonstrated.<br />
<br />
Lightly staining nerves occur among the muscle bundles and in the fibrosa.<br />
<br />
<peir-vm>UAB-Histology-00265</peir-vm><br />
<br />
== Placenta and Umbilical Cord ==<br />
<br />
Slides: 275, 264, 273, 274, 279, 280.<br />
<br />
=== Slide 275, Chorionic Villi (H&E) ===<br />
<br />
This is a section of a small part of a fetal placenta of a very early pregnancy, showing chorionic villi and the surrounding maternal blood spaces. Some slides have a strip of chorionic plate across the upper margin of the section.<br />
<br />
Chorionic plate<br />
<br />
The greater part of the plate is chorion, composed of a mass of embryonic connective tissue (large fibroblasts, fine collagenous fibers, abundant ground substance), covered on its lower surface by a double layer of epithelial cells: the cytotrophoblast adjacent to the connective tissue, and the syntrophoblast (syncytial trophoblast) on the free surface, bordering on maternal blood spaces.<br />
<br />
Cells of the syntrophoblast do not show cell boundaries. Ragged cell surfaces indicate microvilli. Cells of the cytotrophoblast supposedly show cell boundaries but they are not readily seen here. They divide to form syntrophoblast.<br />
<br />
Note blood vessels in the connective tissue (branches of umbilical vessels) containing nucleated fetal red blood corpuscles.<br />
<br />
The small zone of looser connective tissue in the upper part of the chorionic plate is part of the amnion. The cuboidal surface epithelium has been torn off.<br />
<br />
Chorionic villi. The villi are outgrowths from the chorion, having the same structure as the chorion. They increase in size and branch repeatedly as they invade the maternal blood spaces. The initial larger villi will become the anchoring villi that will penetrate the endometrium (decidua basalis) to anchor the fetal placenta. Smaller villi sprout off the anchoring villi.<br />
<br />
Note that the villi vary in size. The largest ones are potential anchoring villi. Others are floating villi; their free ends are in the blood spaces.<br />
<br />
Each villus has a core of embryonic connective tissue, branches of umbilical vessels (sparse in this early placenta), and a covering of inner cytotrophoblast and superficial syntrophoblast.<br />
<br />
<peir-vm>UAB-Histology-00275</peir-vm><br />
<br />
=== Slide 264, Uterus and Placenta from a later stage of pregnancy (PASH) === <br />
<br />
Look at the fetal placenta.<br />
<br />
Villi are larger and more numerous than in slide 275, stroma is generally more compact with more collagenous fibers (still fine) and abundant fibroblasts.<br />
<br />
Blood vessels in the villi are more numerous. Capillaries and little venules are peripherally located close to the trophoblast cells, although this may not be obvious due to plane of sections. Note that now red blood corpuscles are not nucleated.<br />
<br />
Syntrophoblast and cytotrophoblast are still present but cytotrophoblast is incomplete in many areas. (It will disappear entirely by late pregnancy.)<br />
<br />
Look for macrophages (Hofbauer cells) in the stroma of the villi - large rounded cells whose cytoplasm may have small vacuoles and/or PAS positive granules.<br />
<br />
Look for syncytial knots on the surface of villi or in the intervillous spaces. These are groups of syntrophoblast cells that detach from the villi and float freely in the spaces; progressively more are formed toward term.<br />
<br />
Look for very small deposits of fibrinoid, on or in the villi or in the intervillous spaces, a non-cellular, homogenous, proteinaceous material associated with transplantation immunity to protect the fetus.<br />
<br />
Maternal placenta (decidua basalis) and uterus. The decidua basalis is the name given to the endometrium that underlies the villi of the fetal placenta. Some villi (anchoring villi) penetrate the decidua basalis (endometrium) for varying distances. In doing so, part of the surface of the endometrium has been eroded and destroyed (surface epithelium is missing).<br />
<br />
Look for anchoring villi attaching to the decidua basalis. Note larger fibrinoid deposits and aggregations of syncytial knots in this region.<br />
<br />
In the decidua basalis, note the vast numbers of large and smaller decidual cells with PAS- positive cytoplasm (are storing glycogen) and large, lightly staining nuclei. Cytoplasm of those with less glycogen stains faintly acidophilic or somewhat grayish. Decidual cells are derived from fibroblasts of the endometrium.<br />
<br />
A few glands are seen in the basal zone of the endometrium. They may be dilated, have very low epithelium or hypertrophied epithelium, and have lymphocytic infiltration surrounding some of them.<br />
<br />
Identify the myometrium and note the large size of the muscle fibers that hypertrophy greatly during pregnancy.<br />
<br />
<peir-vm>UAB-Histology-00264</peir-vm><br />
<br />
=== Slide 280. Uterus and Placenta near term (H&E) ===<br />
<br />
Fetal placenta. Proliferation of villi has continued to increase during pregnancy.<br />
<br />
Note the great number of chorionic villi, practically filling the maternal blood spaces. The anchoring villi have become very large. The connective tissue in the core is fibrous, but embryonic connective tissue has persisted at the periphery. The larger blood vessels course in these villi. Observe the variation in size of the floating villi, which continue to form throughout pregnancy.<br />
<br />
In the villi, note further compactness of stroma, areas of more dense collagenous fibers, more capillaries, and venules close to the trophoblast.<br />
<br />
Look for macrophages (Hofbauer cells) in the stroma of the villi. With H&E, the cytoplasm is finely vacuolated.<br />
<br />
Syntrophoblasts still cover the surface of the villi. Cytotrophoblasts have generally disappeared.<br />
<br />
Note increased number of syncytial knots and much fibrinoid material. Knots are seen deep in the endometrium; they appear as darkly stained groups of pyknotic nuclei.<br />
<br />
The maternal placenta (decidua basalis).<br />
<br />
Again note the placental villi anchoring into the endometrium.<br />
<br />
Decidual cells are still present in the endometrium but many have “used up” their glycogen and are reverting to fibroblasts. Lymphocytic infiltration is seen in places. Much fibrinoid is present.<br />
<br />
Uterine glands, whose basal portions had remained inactive, are proliferating and regenerating. Some appear cystic.<br />
<br />
Uterine Muscularis.<br />
<br />
The three layers are not readily identified, but note again the large size of the fibers.<br />
<br />
Note the huge multinucleated giant cells in the deep endometrium and especially in the muscularis. They are thought to be of trophoblastic origin (perhaps differentiated from but not to be confused with syncytial knots).<br />
<br />
<peir-vm>UAB-Histology-00280</peir-vm><br />
<br />
=== Slide 279. Placenta at term (H&E) ===<br />
<br />
These slides are from a “fresh” placenta immediately after parturition; thus very little postmortem change is present and structures are seen distinctly.<br />
<br />
Go over the fetal placenta as in slide 280. Numerous red blood corpuscles are present in the maternal blood spaces, probably due to rupture of blood vessels during parturition.<br />
<br />
Note the tremendous vascularity of the placental villi, apparent here because of the fresh condition of the tissues; note also the great number of syncytial knots.<br />
<br />
A fragment of decidua basalis may be present (left end of the section in the field). Anchoring villi are seen and large decidual cells may still be present.<br />
<br />
<peir-vm>UAB-Histology-00279</peir-vm><br />
<br />
=== Slide 274, Placenta at term (PASH) ===<br />
<br />
This tissue is from the same placenta used for making slides 279 and 273. Look at the slide to see how term structures stain with PASH.<br />
<br />
Basement membranes are prominent under the syntrophoblast and under endothelium of the blood vessels. Note also that blood vessels are more numerous in these villi than in those of slide 280, are also congested which may be the cause of their large size.<br />
<br />
Areas of decidua basalis are present.<br />
<br />
<peir-vm>UAB-Histology-00274</peir-vm><br />
<br />
=== Slide 273, Placenta, term (Masson) ===<br />
<br />
This tissue is from the same placenta as used for making slides 274 and 279.<br />
<br />
Identify the structures as seen with this stain. Connective tissue elements are blue, nuclei are reddish or indistinct, and the cytoplasm varies. <br />
<br />
This section shows the chorionic plate at the right (in the field).<br />
<br />
The outer “membrane” is the amnion, consisting of a layer of cuboidal or low columnar epithelium and a thin layer of connective tissue. It is mechanically separated from the underlying chorion.<br />
<br />
The chorion consists of a layer of connective tissue covered by syncytial trophoblast that is now mostly fibrinoid.<br />
<br />
Two main umbilical vessels and smaller branches are passing through the chorionic plate.<br />
<br />
<peir-vm>UAB-Histology-00273</peir-vm><br />
<br />
== Umbilical Cord ==<br />
<br />
=== Slide 287, Umbilical Cords (H&E) ===<br />
<br />
Slide 287, Umbilical Cords (H&E), is from an early pregnancy and from late in pregnancy.<br />
<br />
The early pregnancy umbilical cord is on the left. The two umbilical arteries and the umbilical vein look generally similar because of the atypical large amount of muscle in the wall. An internal elastic membrane is lacking in the arteries. The diameter of the vein is greater than that of the artery and the muscle is not quite as compactly arranged.<br />
<br />
The stroma of the cord is mucous connective tissue - embryonic connective tissue with a mucoid ground substance (Wharton’s jelly) which is removed in section preparation. Note the fine collagenous fibers and the large branched fibroblasts.<br />
<br />
Covering the cord is simple squamous or simple cuboidal epithelium, part of the amnion.<br />
<br />
<peir-vm>UAB-Histology-00287</peir-vm><br />
<br />
=== Slides 287 (tissue on right) and Slide 277, umbilical cord at term (H&E) ===<br />
<br />
In this fully developed placenta, the atypical structure of the arteries is well shown - a wide inner layer of longitudinally arranged muscle and a thick outer circular layer. Postmortem contraction causes collapse of the vessels. The vein has some inner longitudinal muscle; most of it is outer circular. Reticular fibers between muscle fibers are seen with H&E (due to postmortem shrinkage of muscle fibers). The small vacuoles are probably early degenerative changes.<br />
<br />
Collagenous fibers in the stroma are somewhat heavier than in the earlier cord but are not mature fibers. Mucous connective tissue retains its embryonic nature; note that fibroblasts are still large branched cells.<br />
<br />
Neutrophils are invading some areas of the stroma (lower field especially), also related to breakdown of the tissues.<br />
<br />
Epithelium of the amnion surrounds the cord.<br />
<br />
==== Slide 287, Umbilical Cord at term (tissue on right) (H&E) ====<br />
<peir-vm>UAB-Histology-00287</peir-vm><br />
==== Slide 277, Umbilical Cord at term (H&E) ====<br />
<peir-vm>UAB-Histology-00277</peir-vm><br />
<br />
{{Template:Histologic}}<br />
<br />
[[Category:Histologic]]</div>Matthew Andersonhttps://peir.path.uab.edu/index.php?title=Template:Histologic&diff=3254Template:Histologic2014-07-21T19:29:05Z<p>Matthew Anderson: </p>
<hr />
<div>{{Navbox<br />
|name = Histologic<br />
|title = [[Histologic]]<br />
|bodyclass = hlist<br />
[[Histologic]]<br />
|group1 = [[Histologic:Chapter 1|Chapter 1]]<br />
|list1 =<br />
* [[Histologic:Chapter 1#Introduction|Introduction]]<br />
* [[Histologic:Chapter 1#Overview_of_Tissue_Preparation_and_Staining_for_Microscopy|Overview of Tissue Preparation and Staining for Microscopy]]<br />
* [[Histologic:Chapter 1#Using_Histologic|Using Histologic]]<br />
|group2 = [[Histologic:Chapter 2|Chapter 2]]<br />
|list2 =<br />
* [[Histologic:Chapter 2#Cells,_Organelles,_and_Inclusions|Cells, Organelles, and Inclusions]]<br />
* [[Histologic:Chapter 2#Mitosis|Mitosis]]<br />
|group3 = [[Histologic:Chapter 3|Chapter 3]]<br />
|list3 =<br />
* [[Histologic:Chapter 3#Introduction|Introduction]]<br />
* [[Histologic:Chapter 3#Simple_Epithelium|Simple Epithelium]]<br />
* [[Histologic:Chapter 3#Stratified_Epithelium|Stratified Epithelium]]<br />
|group4 = [[Histologic:Chapter 4|Chapter 4]]<br />
|list4 =<br />
* [[Histologic:Chapter 4#Introduction|Introduction]]<br />
* [[Histologic:Chapter 4#Loose_Connective_Tissue|Loose Connective Tissue]]<br />
* [[Histologic:Chapter 4#Dense_Connective_Tissue|Dense Connective Tissue]]<br />
* [[Histologic:Chapter 4#Adipose_Tissue|Adipose Tissue]]<br />
|group5 = [[Histologic:Chapter 5|Chapter 5]]<br />
|list5 =<br />
* [[Histologic:Chapter 5#Introduction|Introduction]]<br />
* [[Histologic:Chapter 5#Smooth_Muscle|Smooth Muscle]]<br />
* [[Histologic:Chapter 5#Skeletal_Muscle|Skeletal Muscle]]<br />
* [[Histologic:Chapter 5#Cardiac_Muscle|Cardiac Muscle]]<br />
|group6 = [[Histologic:Chapter 6|Chapter 6]]<br />
|list6 =<br />
* [[Histologic:Chapter 6#Introduction|Introduction]]<br />
* [[Histologic:Chapter 6#Nerve_Fibers_And_Nerves|Nerve Fibers And Nerves]]<br />
* [[Histologic:Chapter 6#Central_Nervous_System:_Brain|Central Nervous System: Brain]]<br />
* [[Histologic:Chapter 6#Spinal_Cord_-_General_Structure|Spinal Cord - General Structure]]<br />
* [[Histologic:Chapter 6#Sympathetic_Chain_Ganglion_With_Multipolar_Neurons|Sympathetic Chain Ganglion With Multipolar Neurons]]<br />
* [[Histologic:Chapter 6#Parasympathetic_Ganglia|Parasympathetic Ganglia]]<br />
|group7 = [[Histologic:Chapter 7|Chapter 7]]<br />
|list7 =<br />
* [[Histologic:Chapter 7#Introduction|Introduction]]<br />
* [[Histologic:Chapter 7#Blood_Smears|Blood Smears]]<br />
|group8 = [[Histologic:Chapter 8|Chapter 8]]<br />
|list8 =<br />
* [[Histologic:Chapter 8#Introduction|Introduction]]<br />
* [[Histologic:Chapter 8#Lymph_Nodes|Lymph Nodes]]<br />
* [[Histologic:Chapter 8#Thymus|Thymus]]<br />
* [[Histologic:Chapter 8#Tonsils|Tonsils]]<br />
* [[Histologic:Chapter 8#Spleen|Spleen]]<br />
|group9 = [[Histologic:Chapter 9|Chapter 9]]<br />
|list9 =<br />
* [[Histologic:Chapter 9#Introduction|Introduction]]<br />
* [[Histologic:Chapter 9#Small_Blood_Vessels|Small Blood Vessels]]<br />
* [[Histologic:Chapter 9#Medium-Sized_Blood_Vessels|Medium-Sized Blood Vessels]]<br />
* [[Histologic:Chapter 9#Large_Arteries|Large Arteries]]<br />
* [[Histologic:Chapter 9#Large_Veins|Large Veins]]<br />
|group10 = [[Histologic:Chapter 10|Chapter 10]]<br />
|list10 =<br />
* [[Histologic:Chapter 10#Olfactory_Area|Olfactory Area]]<br />
* [[Histologic:Chapter 10#Epiglottis|Epiglottis]]<br />
* [[Histologic:Chapter 10#Trachea|Trachea]]<br />
* [[Histologic:Chapter 10#Bronchi,_Bronchioles,_and_Lung|Bronchi, Bronchioles, and Lung]]<br />
|group11 = [[Histologic:Chapter 11|Chapter 11]]<br />
|list11 =<br />
* [[Histologic:Chapter 11#Lip|Lip]]<br />
* [[Histologic:Chapter 11#Tongue|Tongue]]<br />
* [[Histologic:Chapter 11#Salivary_Glands|Salivary Glands]]<br />
* [[Histologic:Chapter 11#Pancreas|Pancreas]]<br />
* [[Histologic:Chapter 11#Esophagus|Esophagus]]<br />
* [[Histologic:Chapter 11#Stomach|Stomach]]<br />
* [[Histologic:Chapter 11#Small_Intestine|Small Intestine]]<br />
* [[Histologic:Chapter 11#Pylorus-Duodenal_Junction|Pylorus-Duodenal Junction]]<br />
* [[Histologic:Chapter 11#Duodenum|Duodenum]]<br />
* [[Histologic:Chapter 11#Jejunum|Jejunum]]<br />
* [[Histologic:Chapter 11#Ileum|Ileum]]<br />
* [[Histologic:Chapter 11#Appendix|Appendix]]<br />
* [[Histologic:Chapter 11#Colon|Colon]]<br />
* [[Histologic:Chapter 11#Rectum|Rectum]]<br />
* [[Histologic:Chapter 11#Anal_Canal|Anal Canal]]<br />
|group12 = [[Histologic:Chapter 12|Chapter 12]]<br />
|list12 =<br />
* [[Histologic:Chapter 12#Introduction|Introduction]]<br />
* [[Histologic:Chapter 12#Gallbladder|Gallbladder]]<br />
|group13 = [[Histologic:Chapter 13|Chapter 13]]<br />
|list13 =<br />
* [[Histologic:Chapter 13#Skeletal_Muscle|Skeletal Muscle]]<br />
* [[Histologic:Chapter 13#Cartilage|Cartilage]]<br />
* [[Histologic:Chapter 13#Bone|Bone]]<br />
* [[Histologic:Chapter 13#Joints|Joints]]<br />
|group14 = [[Histologic:Chapter 14|Chapter 14]]<br />
|list14 =<br />
* [[Histologic:Chapter 14#Introduction|Introduction]]<br />
* [[Histologic:Chapter 14#Pituitary_Gland_(Hypophysis)|Pituitary Gland (Hypophysis)]]<br />
* [[Histologic:Chapter 14#Thyroid|Thyroid]]<br />
* [[Histologic:Chapter 14#Parathyroid|Parathyroid]]<br />
* [[Histologic:Chapter 14#Suprarenal_(Adrenal)_Glands|Suprarenal (Adrenal) Glands]]<br />
* [[Histologic:Chapter 14#Endocrine_Pancreas_(Pancreatic_Islets_of_Langerhans)|Endocrine Pancreas (Pancreatic Islets of Langerhans)]]<br />
|group15 = [[Histologic:Chapter 15|Chapter 15]]<br />
|list15 =<br />
* [[Histologic:Chapter 15#Kidney|Kidney]]<br />
* [[Histologic:Chapter 15#Ureter_and_Urinary_Bladder|Ureter And Urinary Bladder]]<br />
|group16 = [[Histologic:Chapter 16|Chapter 16]]<br />
|list16 =<br />
* [[Histologic:Chapter 16#Introduction|Introduction]]<br />
* [[Histologic:Chapter 16#The_Testis|The Testis]]<br />
* [[Histologic:Chapter 16#Genital_Ducts|Genital Ducts]]<br />
* [[Histologic:Chapter 16#Accessory_Glands|Accessory Glands]]<br />
* [[Histologic:Chapter 16#Penis|Penis]]<br />
|group17 = [[Histologic:Chapter 17|Chapter 17]]<br />
|list17 =<br />
* [[Histologic:Chapter 17#Introduction|Introduction]]<br />
* [[Histologic:Chapter 17#Ovary|Ovary]]<br />
* [[Histologic:Chapter 17#Uterine_Tube|Uterine Tube]]<br />
* [[Histologic:Chapter 17#Uterus|Uterus]]<br />
* [[Histologic:Chapter 17#Vagina|Vagina]]<br />
* [[Histologic:Chapter 17#Placenta_and_Umbilical_Cord|Placenta and Umbilical Cord]]<br />
* [[Histologic:Chapter 17#Umbilical_Cord|Umbilical Cord]]<br />
|group18 = [[Histologic:Chapter 18|Chapter 18]]<br />
|list18 =<br />
* [[Histologic:Chapter 18#Introduction|Introduction]]<br />
|group19 = [[Histologic:Chapter 19|Chapter 19]]<br />
|list19 =<br />
* [[Histologic:Chapter 19#Introduction|Introduction]]<br />
|group20 = [[Histologic:Contributors|Contributors]]<br />
|list20 =<br />
* [[Histologic:Contributors#Acknowledgements|Acknowledgements]]<br />
* [[Histologic:Contributors#Staff|Staff]]<br />
<br />
}}<noinclude><br />
<br />
[[Category:Histologic Templates]]<br />
[[Category:Histologic]]<br />
</noinclude></div>Matthew Andersonhttps://peir.path.uab.edu/index.php?title=Histologic&diff=3253Histologic2014-07-21T19:28:26Z<p>Matthew Anderson: </p>
<hr />
<div>Welcome to [[Histologic]], a constantly-updated, wiki-based comprehensive manual for the teaching of histology at the [http://www.uab.edu/medicine/home/ University of Alabama at Birmingham School of Medicine]. It integrates still images from the [{{SERVER}}/library PEIR Digital Library] and whole slide images from the [http://peir-vm.path.uab.edu PEIR-VM] project. For usage instructions, please see [[Histologic:Chapter 1|Chapter 1]]. To get in touch with us, please see [[Histologic:Contributors|Contributors]].<br />
<br />
== [[Histologic:Chapter 1|Chapter 1: Overview]] ==<br />
* [[Histologic:Chapter 1#Introduction|Introduction]]<br />
* [[Histologic:Chapter 1#Overview_of_Tissue_Preparation_and_Staining_for_Microscopy|Overview of Tissue Preparation and Staining for Microscopy]]<br />
* [[Histologic:Chapter 1#Using_Histologic|Using Histologic]]<br />
<br />
== [[Histologic:Chapter 2|Chapter 2: The Cell]] ==<br />
* [[Histologic:Chapter 2#Cells,_Organelles,_and_Inclusions|Cells, Organelles, and Inclusions]]<br />
* [[Histologic:Chapter 2#Mitosis|Mitosis]]<br />
<br />
== [[Histologic:Chapter 3|Chapter 3: Epithelial Cells]] ==<br />
* [[Histologic:Chapter 3#Introduction|Introduction]]<br />
* [[Histologic:Chapter 3#Simple_Epithelium|Simple Epithelium]]<br />
* [[Histologic:Chapter 3#Stratified_Epithelium|Stratified Epithelium]]<br />
<br />
== [[Histologic:Chapter 4|Chapter 4: Support Cells and the Extracellular Matrix]] ==<br />
* [[Histologic:Chapter 4#Introduction|Introduction]]<br />
* [[Histologic:Chapter 4#Loose_Connective_Tissue|Loose Connective Tissue]]<br />
* [[Histologic:Chapter 4#Dense_Connective_Tissue|Dense Connective Tissue]]<br />
* [[Histologic:Chapter 4#Adipose_Tissue|Adipose Tissue]]<br />
<br />
== [[Histologic:Chapter 5|Chapter 5: Contractile Cells]] ==<br />
* [[Histologic:Chapter 5#Introduction|Introduction]]<br />
* [[Histologic:Chapter 5#Smooth_Muscle|Smooth Muscle]]<br />
* [[Histologic:Chapter 5#Skeletal_Muscle|Skeletal Muscle]]<br />
* [[Histologic:Chapter 5#Cardiac_Muscle|Cardiac Muscle]]<br />
<br />
== [[Histologic:Chapter 6|Chapter 6: Nervous Tissue]] ==<br />
* [[Histologic:Chapter 6#Introduction|Introduction]]<br />
* [[Histologic:Chapter 6#Nerve_Fibers_And_Nerves|Nerve Fibers And Nerves]]<br />
* [[Histologic:Chapter 6#Central_Nervous_System:_Brain|Central Nervous System: Brain]]<br />
* [[Histologic:Chapter 6#Spinal_Cord_-_General_Structure|Spinal Cord - General Structure]]<br />
* [[Histologic:Chapter 6#Sympathetic_Chain_Ganglion_With_Multipolar_Neurons|Sympathetic Chain Ganglion With Multipolar Neurons]]<br />
* [[Histologic:Chapter 6#Parasympathetic_Ganglia|Parasympathetic Ganglia]]<br />
<br />
== [[Histologic:Chapter 7|Chapter 7: Blood Cells]] ==<br />
* [[Histologic:Chapter 7#Introduction|Introduction]]<br />
* [[Histologic:Chapter 7#Blood_Smears|Blood Smears]]<br />
<br />
== [[Histologic:Chapter 8|Chapter 8: Immune System]] ==<br />
* [[Histologic:Chapter 8#Introduction|Introduction]]<br />
* [[Histologic:Chapter 8#Lymph_Nodes|Lymph Nodes]]<br />
* [[Histologic:Chapter 8#Thymus|Thymus]]<br />
* [[Histologic:Chapter 8#Tonsils|Tonsils]]<br />
* [[Histologic:Chapter 8#Spleen|Spleen]]<br />
<br />
== [[Histologic:Chapter 9|Chapter 9: Blood and Lymphatic Circulatory Systems and Heart]] ==<br />
* [[Histologic:Chapter 9#Introduction|Introduction]]<br />
* [[Histologic:Chapter 9#Small_Blood_Vessels|Small Blood Vessels]]<br />
* [[Histologic:Chapter 9#Medium-Sized_Blood_Vessels|Medium-Sized Blood Vessels]]<br />
* [[Histologic:Chapter 9#Large_Arteries|Large Arteries]]<br />
* [[Histologic:Chapter 9#Large_Veins|Large Veins]]<br />
<br />
== [[Histologic:Chapter 10|Chapter 10: Respiratory System]] ==<br />
* [[Histologic:Chapter 10#Olfactory_Area|Olfactory Area]]<br />
* [[Histologic:Chapter 10#Epiglottis|Epiglottis]]<br />
* [[Histologic:Chapter 10#Trachea|Trachea]]<br />
* [[Histologic:Chapter 10#Bronchi,_Bronchioles,_and_Lung|Bronchi, Bronchioles, and Lung]]<br />
<br />
== [[Histologic:Chapter 11|Chapter 11: Alimentary Tract]] ==<br />
* [[Histologic:Chapter 11#Lip|Lip]]<br />
* [[Histologic:Chapter 11#Tongue|Tongue]]<br />
* [[Histologic:Chapter 11#Salivary_Glands|Salivary Glands]]<br />
* [[Histologic:Chapter 11#Pancreas|Pancreas]]<br />
* [[Histologic:Chapter 11#Esophagus|Esophagus]]<br />
* [[Histologic:Chapter 11#Stomach|Stomach]]<br />
* [[Histologic:Chapter 11#Small_Intestine|Small Intestine]]<br />
* [[Histologic:Chapter 11#Pylorus-Duodenal_Junction|Pylorus-Duodenal Junction]]<br />
* [[Histologic:Chapter 11#Duodenum|Duodenum]]<br />
* [[Histologic:Chapter 11#Jejunum|Jejunum]]<br />
* [[Histologic:Chapter 11#Ileum|Ileum]]<br />
* [[Histologic:Chapter 11#Appendix|Appendix]]<br />
* [[Histologic:Chapter 11#Colon|Colon]]<br />
* [[Histologic:Chapter 11#Rectum|Rectum]]<br />
* [[Histologic:Chapter 11#Anal_Canal|Anal Canal]]<br />
<br />
== [[Histologic:Chapter 12|Chapter 12: Liver]] ==<br />
* [[Histologic:Chapter 12#Introduction|Introduction]]<br />
* [[Histologic:Chapter 12#Gallbladder|Gallbladder]]<br />
<br />
== [[Histologic:Chapter 13|Chapter 13: Musculoskeletal System]] ==<br />
* [[Histologic:Chapter 13#Skeletal_Muscle|Skeletal Muscle]]<br />
* [[Histologic:Chapter 13#Cartilage|Cartilage]]<br />
* [[Histologic:Chapter 13#Bone|Bone]]<br />
* [[Histologic:Chapter 13#Joints|Joints]]<br />
<br />
== [[Histologic:Chapter 14|Chapter 14: Endocrine System]] ==<br />
* [[Histologic:Chapter 14#Introduction|Introduction]]<br />
* [[Histologic:Chapter 14#Pituitary_Gland_(Hypophysis)|Pituitary Gland (Hypophysis)]]<br />
* [[Histologic:Chapter 14#Thyroid|Thyroid]]<br />
* [[Histologic:Chapter 14#Parathyroid|Parathyroid]]<br />
* [[Histologic:Chapter 14#Suprarenal_(Adrenal)_Glands|Suprarenal (Adrenal) Glands]]<br />
* [[Histologic:Chapter 14#Endocrine_Pancreas_(Pancreatic_Islets_of_Langerhans)|Endocrine Pancreas (Pancreatic Islets of Langerhans)]]<br />
<br />
== [[Histologic:Chapter 15|Chapter 15: Urinary System]] ==<br />
* [[Histologic:Chapter 15#Kidney|Kidney]]<br />
* [[Histologic:Chapter 15#Ureter_and_Urinary_Bladder|Ureter And Urinary Bladder]]<br />
<br />
== [[Histologic:Chapter 16|Chapter 16: Male Reproductive System]] ==<br />
* [[Histologic:Chapter 16#Introduction|Introduction]]<br />
* [[Histologic:Chapter 16#The_Testis|The Testis]]<br />
* [[Histologic:Chapter 16#Genital_Ducts|Genital Ducts]]<br />
* [[Histologic:Chapter 16#Accessory_Glands|Accessory Glands]]<br />
* [[Histologic:Chapter 16#Penis|Penis]]<br />
<br />
== [[Histologic:Chapter 17|Chapter 17: Female Reproductive System]] ==<br />
* [[Histologic:Chapter 17#Introduction|Introduction]]<br />
* [[Histologic:Chapter 17#Ovary|Ovary]]<br />
* [[Histologic:Chapter 17#Uterine_Tube|Uterine Tube]]<br />
* [[Histologic:Chapter 17#Uterus|Uterus]]<br />
* [[Histologic:Chapter 17#Vagina|Vagina]]<br />
* [[Histologic:Chapter 17#Placenta_and_Umbilical_Cord|Placenta and Umbilical Cord]]<br />
* [[Histologic:Chapter 17#Umbilical_Cord|Umbilical Cord]]<br />
<br />
== [[Histologic:Chapter 18|Chapter 18: Skin and Breast]] ==<br />
* [[Histologic:Chapter 18#Introduction|Introduction]]<br />
<br />
== [[Histologic:Chapter 19|Chapter 19: Special Senses]] ==<br />
* [[Histologic:Chapter 19#Introduction|Introduction]]<br />
<br />
== [[Histologic:Contributors|Contributors]] ==<br />
* [[Histologic:Contributors#Acknowledgements|Acknowledgements]]<br />
* [[Histologic:Contributors#Staff|Staff]]<br />
<br />
[[Category:Histologic]]</div>Matthew Andersonhttps://peir.path.uab.edu/index.php?title=Histologic:Chapter_17&diff=3252Histologic:Chapter 172014-07-21T19:23:57Z<p>Matthew Anderson: Created page with "== Introduction == The female reproductive system consists of the ovaries, the two uterine tubes (oviducts or Fallopian tubes) a uterus, a vagina, the external genitalia and ..."</p>
<hr />
<div>== Introduction ==<br />
<br />
The female reproductive system consists of the ovaries, the two uterine tubes (oviducts or Fallopian tubes) a uterus, a vagina, the external genitalia and the mammary glands. Normally, the development of this system requires that the zygote have the XX sex chromosomal complement. The ovaries produce the ova or female germ cells and certain hormones; the uterine tubes are necessary for transporting sperm to the ova for fertilization and for transporting the zygote to the uterus. Growth and maturation of the conceptus occur in the uterus. The vagina and external genitalia are the copulatory organs and the mammary glands serve for nutrition of the newborn.<br />
<br />
== Ovary ==<br />
<br />
With the exception of slide 255, Monkey ovary (PASH), all other slides were obtained from human sources.<br />
<br />
Study first slide 255 since it shows all the representative stages of follicle development. Then study slide 251, Ovary, (H&E); it has very small normal follicles, larger atretic follicles and corpora albicantia. Slide 254 Ovary (Masson) shows a large well-developed corpus luteum and a small atretic follicle with a prominent glassy membrane.<br />
<br />
=== Slide 255, Ovary (PASH) ===<br />
<br />
Slide 255, Ovary (PASH) shows a mature ovary with one large corpus luteum, several large preovulatory follicles, smaller growing follicles, and atretic follicles. Only a portion of the whole ovary is on the slide. <br />
<br />
Study the cortex of the ovary.<br />
<br />
Identify the surface epithelium (germinal epithelium), the tunica albuginea (a zone immediately beneath the surface epithelium which is more compact and less cellular than the stroma) and the stroma of cellular connective tissue.<br />
<br />
Study the various stages of follicles.<br />
<br />
Primordial (unilaminar follicles) consists of a small primary oocyte surrounded by a single layer of squamous follicular cells which rest on a basement membrane.<br />
<br />
A primary follicle contains an enlarging oocyte surrounded by a single layer of flattened, cuboidal or low columnar follicular cells. These cells give rise to granulosa cells by mitosis.<br />
<br />
Growing or multilaminar follicles are surrounded by several layers of follicular cells.<br />
<br />
Vesicular (secondary or antral) follicles consist of a primary oocyte surrounded by 6-12 layers of granulosa cells. Fluid-filled spaces that appear between the granulosa cells gradually enlarge, interconnect, and eventually form a crescent-shaped cavity, the antrum.<br />
<br />
Note the PAS-positive staining basement membrane located between the outer row of granulosa cells of the follicle and the stromal cells. Observe that the stromal cells are organized as a sheath of cells around the growing follicles.<br />
<br />
The vesicular follicles are surrounded by a stromal sheath called the theca folliculi; the theca is divided into two regions, a theca interna and a theca externa.<br />
<br />
The theca interna is a zone of epithelioid stromal cells surrounding the outer granulosa cells but separated from them by the basement membrane; this portion of the theca is vascular, containing capillaries and smaller blood vessels.<br />
<br />
The theca externa lies external to the theca interna and consists of condensed stroma.<br />
<br />
As the follicle enlarges, so does the oocyte. Increase in volume of both the nucleus and the cytoplasm accounts for oocyte enlargement. Observe the prominent nucleolus and the nuclear membrane of the oocytes; note that the cytoplasm is weakly acidophilic.<br />
<br />
The zone pellucida is a prominent PAS-positive staining membrane immediately surrounding the oocyte’s plasma membrane. It is not present in primordial follicles or in smaller growing follicles.<br />
<br />
The degeneration of follicles is called atresia and signs of this activity can be identified as follows:<br />
<br />
*The granulosa cell layer may be partially detached from the theca interna.<br />
*Groups of cells with pyknotic nuclei appear in the granulosa layer. <br />
*Fragmentation of the oocytes may be occurring.<br />
*The oocyte nucleus may be pyknotic (highly condensed and dark staining).<br />
*The basement membrane is very irregular, wavy, and fragmented. <br />
*The zone pellucida is fragmented or broken in places.<br />
<br />
Study the vesicular (secondary or antral) follicles.<br />
<br />
Identify early antrum formation in which the follicular cavity is small. Call-Exner bodies may be present between granulosal cells; they are strongly PAS-positive.<br />
<br />
Find a large follicle (large antrum) in which the large volume of the antrum indicates it is filled with fluid called liquor folliculi.<br />
<br />
The cumulus oophorus is a mound or hill of granulosa cells surrounding and supporting the large oocyte. This structure is present in the mature (Graafian) follicle.<br />
<br />
The corona radiata is a cluster of granulosal cells which immediately surrounds the zona pellucida. When the ovum breaks free from the cumulus oophorus the corona radiata cells “go with it” and surround the ovum during ovulation and transport into the uterine tube.<br />
<br />
Recall that just prior to ovulation, the primary oocyte undergoes its first maturation division, giving off the first polar body, to form a secondary oocyte. The final maturation division will not occur unless fertilization ensues.<br />
<br />
Study the corpus luteum.<br />
<br />
A corpus luteum is a new endocrine organ that makes its appearance after ovulation. The granulosa cells of the follicle hypertrophy, become luteinized and form granulosa lutein cells which secrete primarily progesterone. The corpus luteum on this slide is in an early stage of development. Note its large size. It consists of a thick folded wall and a central cavity (the former antrum of the follicle) which is filling in which fibrin deposits and loose connective tissue growing in from the theca externa. <br />
<br />
Most of the wall is composed of granulosa lutein cells derived from the granulosa cells of the mature follicle. They are large cells with pale cytoplasm and a vesicular nucleus containing a prominent nucleolus. The cell membrane is stained with PAS. The cells are packed closely together, but fibroblasts, fine connective tissue, and capillaries invading from the stroma are penetrating between the cells toward the central cavity.<br />
<br />
The theca lutein cells form a thin zone at the periphery of the corpus luteum and extend into the folds (which were formed when the ruptured follicle collapsed). They are not too apparent with this stain, but they are smaller cells than granulosa lutein cells.<br />
<br />
The former antrum has fibrin deposits and is filling in with loose connective tissue.<br />
<br />
The remains of atretic follicles can be seen as small irregular, intensely stained PAS-positive structures that are hypertrophied zona pellucida remnants from atretic follicles. They may or may not be surrounded by a greatly thickened folded glassy membrane (basement membrane) which stains pink. Both structures will be replaced by stroma.<br />
<br />
<br />
Study the medulla of the ovary.<br />
<br />
The medulla contains fibroelastic tissue, many large and smaller vessels, nerves, and lymphatics. Most of the blood vessels are highly coiled or convoluted.<br />
<br />
The medulla is continuous with the connective tissue of the mesovarium, a short peritoneal fold that attaches the ovary to the broad ligament; the point of attachment serves as a hilus for the ovary. The mesothelium of the serosa (visceral peritoneum) of the mesovarium is continuous with the surface epithelium of the ovary.<br />
<br />
A homologue to the rete testis in the male, the rete ovarii, can be seen in one part of the medulla (upper left in the field). They are distinguished by small, deeply basophilic nuclei of cuboidal cells lining an irregular-shaped lumen.<br />
<br />
<peir-vm>UAB-Histology-00255</peir-vm><br />
<br />
<br />
=== Slide 251, Ovary, Human (H&E) (From an elderly woman) === <br />
<br />
Study the cortex of this ovary.<br />
<br />
Note the prominent tunica albuginea just underneath the surface epithelium. The single layer of simple cuboidal cells making up the surface epithelium is present only in patches since part of it was sloughed off during preparation of the tissue.<br />
<br />
The stroma is much more evident on this slide as compared with the monkey ovary just studied. Note the swirling pattern of the stromal cells, especially how they begin to swirl and encircle a follicle some distance from the follicle. In growing follicles, the stromal cells begin to condense into the thecal follicular sheath of cells that contribute to the function of the follicle.<br />
<br />
Find primordial, primary and small growing follicles; (Primordial follicles are rare in mature ovaries). Note those follicles that show signs of atresia.<br />
<br />
The two or three large follicles (preovulatory follicles) on this slide are also in early atresia. Granulosa cells have sloughed off or are still sloughing; the basement membrane in one follicle is beginning to hypertrophy.<br />
<br />
Look for parts of corpora albicantia (singular = corpus albicans) which are fibrous scars that replace regressed corpora lutea; they are composed of compact collagenous fibers and fibroblasts, and have indefinite borders which merge with the stroma<br />
<br />
Study the medulla of this ovary. <br />
<br />
Note numerous, prominent blood vessels of various caliber which take up most of the volume of the medulla. Some of these vessels are quite convoluted (a long row of cross-sections of a vessel, each cross-section of about the same diameter, may be observed.<br />
<br />
Lymphatics are also a prominent feature of the ovarian medulla. They are more difficult to distinguish because their thin walls may have collapsed, eliminating the lumen.<br />
<br />
Vasomotor nerves to the smooth muscles of blood vessels may be seen; they are too small to see clearly.<br />
<br />
<peir-vm>UAB-Histology-00251</peir-vm><br />
<br />
<br />
=== Slide 254, Ovary, Human (Masson) ===<br />
<br />
The principal structure occupying most of this section is a corpus luteum. Other follicles may also be present, but concentrate on the corpus luteum.<br />
<br />
The corpus luteum represents a very young stage of development, soon after ovulation. The amount of connective tissue located in the middle of the corpus luteum indicates the age of the organ. Note the huge size of the corpus luteum; it occupies most of the section.<br />
<br />
Observe again that granulosa lutein cells make up the bulk of the corpus luteum; these are large cells with granular cytoplasm, vesicular nuclei and prominent nucleoli. Due to artifact of preparation or postmortem changes the cells are separated from each other by spaces.<br />
<br />
The granulosa lutein cells are arranged into groups separated by delicate strands of connective tissue and capillaries.<br />
<br />
In the central cavity are strands of clotted blood (red blood corpuscles and precipitated fibrin) and fine fibrin filaments. Little or no connective tissue is present as yet.<br />
<br />
Numerous dilated blood vessels are seen in the stroma around the periphery of the corpus luteum, probably still in this state from their preovulatory condition.<br />
<br />
The blue-staining connective tissue on the outer margin of the corpus luteum represents the former theca externa.<br />
<br />
Theca lutein cells are present on the periphery and in the folds of this corpus luteum but are not yet well differentiated, thus are not easily identified. Blood vessels and connective tissue will be growing in from the former theca externa.<br />
<br />
If fertilization does not take place, the corpus luteum persists for about two weeks, and then it breaks down (regresses) to become a corpus albicans. The corpus luteum in this case is called a corpus luteum spurium (false) or corpus luteum of menstruation.<br />
<br />
If fertilization occurs, the corpus luteum persists, gets larger, and lasts longer; it is now called a corpus luteum verum (true) or corpus luteum of pregnancy.<br />
<br />
<peir-vm>UAB-Histology-00254</peir-vm><br />
<br />
<br />
== Uterine Tube ==<br />
<br />
Each uterine tube is about 12 cm long and serves to connect the uterus with the ovaries for transport of spermatozoa, fertilization of the ovum and nourishment and transport of the zygote. The uterine tube is embedded in (courses through) the mesosalpinx which is the upper part of the broad ligament of the uterus. Within this mesentery of the uterine tube is a central core of connective tissue, some smooth muscle, blood vessels and nerves, and it is covered by a serosa (peritoneum). Thus the wall of the uterine tube consists of three layers: a mucosa, a muscularis and a serosa.<br />
<br />
Four regions of the uterine tube are generally recognized; from the uterus distally they are the interstitial (intramural) segment, the isthmus, the ampulla and the infundibulum. Only two regions or segments are represented in these slides. These are slides of the ampulla (slides 256, 257 and 258 and of the isthmus (slide 259).<br />
<br />
=== Slide 257, Uterine Tube Ampulla (Masson) ===<br />
<br />
Study the mucosa (mucous membrane) of this section of the uterine tube; note the complex foldings of the mucosa. The epithelium is actually simple columnar, but it frequently appears pseudostratified. It is tallest in the ampulla and decreases in height towards the uterus.<br />
<br />
The epithelium consists of two types of cells, ciliated columnar cells (numerous on the fimbria and in the ampulla) and non-ciliated columnar secretory cells (peg cells).<br />
<br />
The thin lamina propria is a primitive type of connective tissue, quite cellular; it extends into the folds. It is loosely arranged in the ampulla and is quite vascular. (It undergoes a decidual reaction, resembling decidual stromal cells found in the endometrium of the pregnant uterus, when tubal pregnancy occurs).<br />
<br />
Observe the muscularis (muscular coat). It has two ill-defined smooth muscle layers; the inner spiral circular layer is thicker than the outer longitudinal muscle layer. Fine connective tissue intermingles with smooth muscle cells.<br />
<br />
Surrounding the muscularis and intermingling with it is vascular connective tissue of the mesosalpinx. Note here the numerous greatly congested blood vessels of various diameters. Such congestion usually indicates a preovulatory state. A serosa forms the outermost layer.<br />
<br />
<peir-vm>UAB-Histology-00257</peir-vm><br />
<br />
=== Slide 258, Uterine Tube, Ampulla (PASH) ===<br />
<br />
This section of uterine tube is also from the ampulla in a pre-ovulatory state.<br />
<br />
The two epithelial cell types can be identified; there appear to be fewer ciliated cells (may be post-mortem loss). PAS clearly demonstrates basement membranes of the epithelial cells as well as elastic membranes in blood vessels.<br />
<br />
In the lamina propria, the looseness of the connective tissue in the folds is better demonstrated than in slide 257. Note branched fibroblasts and scattered lymphocytes. Lymphocytes may also be seen migrating through the epithelium to be eliminated from the body. Many dilated blood vessels are seen in this region.<br />
<br />
The muscularis appears as patches of smooth muscle fibers dispersed among a loose arrangement of connective tissue fibers. Numerous dilated blood vessels are interspersed in the connective tissue among the bundles of muscle fibers.<br />
<br />
<peir-vm>UAB-Histology-00258</peir-vm><br />
<br />
=== Slide 256, Uterine Tube (Ampulla) of Pregnancy (Masson) ===<br />
<br />
This section represents uterine tube removed from a pregnant woman. There are artifactual breaks in the tissue section. <br />
<br />
Identify the cell types in the epithelium. Nonciliated peg cells are most predominant, but this varies from place to place. The connective tissue of the lamina propria has proliferated to appear more like a primitive connective tissue; lymphocytes are more numerous. In the connective tissue you may be able to see large, pale-staining decidual cells which look like macrophages. These are glycogen storing cells that occur in great numbers in the uterus during pregnancy.<br />
<br />
Lymphocytes, decidual cells, and other cells appear to be working their way between the epithelial cells into the lumen, probably a reaction to an interrupted pregnancy. They are surrounded by a vacuole.<br />
<br />
Identify the layers of smooth muscle forming the muscularis, the numerous blood vessels in the connective tissue between the muscle bundles, and serosa covering most of the section.<br />
<br />
<peir-vm>UAB-Histology-00256</peir-vm><br />
<br />
=== Slide 259, Uterine Tube (Masson) ===<br />
<br />
This section is from the isthmus segment of the uterine tube, which lies along the uterine wall. Compare with slide 257, ampulla.<br />
<br />
Observe the size of the lumen, the degree of mucosal folding, the height of the epithelium and the width of the lamina propria and the muscularis. The mucosal foldings are much less complex than in the ampulla.<br />
<br />
Due to the thickness of this section of uterine tube its epithelium appears to be pseudostratified tall columnar. The nuclei are elongated and a few cells appear ciliated.<br />
<br />
The lamina propria is more compact in the isthmus than in the folds of the ampulla.<br />
<br />
Compare this section with that of the ductus deferens (slide 232) with which it might be confused. One should be able to distinguish them by the epithelium and by the layers of muscle.<br />
<br />
<peir-vm>UAB-Histology-00259</peir-vm><br />
<br />
<br />
== Uterus ==<br />
<br />
The uterine slides demonstrate two phases of the menstrual cycle and one of pregnancy. No slides are available from premenstrual and menstrual phases of the uterus.<br />
<br />
Slide 278 (H&E) is from the early proliferative phase.<br />
<br />
Slide 261 (H&E) is from the proliferative phase.<br />
<br />
Slide 262 (H&E) is from the secretory phase.<br />
<br />
Slide 264 (PASH) is from pregnant uterus; it shows decidual cells in the stroma and also has some placenta attached to it.<br />
<br />
=== Slide 278, Uterus, cross-section (H&E) ===<br />
<br />
Slide 278, Uterus, cross-section (H&E), shows endometrium in early to mid- proliferative phase of the menstrual cycle (days 7 to 9).<br />
<br />
Identify: endometrium (mucosa), myometrium (muscularis), and perimetrium (serosa).<br />
<br />
Study the endometrium.<br />
<br />
Distinguish two zones in the endometrium:<br />
<br />
*The basalis (deep layer) where the stroma is compact and glands are branched.<br />
<br />
*The functionalis, the entire endometrium above this. The stroma is not as compact as in the basal layer, but is quite dense in comparison with endometrium in later phases of the cycle.<br />
<br />
Note the simple columnar surface epithelium; it may appear pseudostratified but all nuclei are similar, therefore all cells are columnar. Occasional lymphocytes lying in a small vacuole are seen in the columnar cells.<br />
<br />
Simple tubular glands indent from the surface epithelium and extend through the thickness of the endometrium, becoming branched in their deepest parts. Some glands may extend into the myometrium for a short distance. The glandular epithelium is simple columnar that may also appear pseudostratified. Cytoplasm is very granular. Nuclei are basally located. Epithelium is proliferating; look for mitotic figures.<br />
<br />
The stroma is a “cellular” connective tissue, with fibroblasts with large oval nuclei and branching cell processes embedded in fine collagenous and reticular fibers. It resembles embryonic connective tissue. Some proliferation of fibroblasts is still in progress; look for mitotic figures. Some lymphocytes are present, especially in the most peripheral stroma. Note that the stroma is denser in the basal layer. This region remains relatively inactive.<br />
<br />
Look for coiled arteries in the lower fourth or third of the endometrium. Later, they will extend almost to the surface. A group of cross sections of these arterioles or very small arteries represents one coiled artery. Capillaries and venules are throughout the endometrium.<br />
<br />
Myometrium (muscularis).<br />
<br />
Note the thickness of the myometrium and the density of the muscle. Attempt to define the three layers of muscle but in a section it is difficult to do so.<br />
<br />
Stratum subvasculare, adjacent to the endometrium. Muscle fibers are in compact bundles, in cross or oblique sections (course longitudinally in the intact uterus), with prominent septa between them.<br />
<br />
Stratum vasculare, the middle layer, the thickest part of the muscularis. Interlacing bundles of muscle course both circularly and spirally.<br />
<br />
Note the large blood vessels in the deeper part of this stratum. Their peculiarities are normal for the uterus. These include muscle in the intima of the arteries, increased muscle in the media of the veins, and sometimes muscle in the adventitia of both. (Some arteries in this slide have arteriosclerosis or intimal hyalinzation.)<br />
<br />
Stratum supravasculare, the thin most peripheral layer, with longitudinal and circular fibers.<br />
<br />
Perimetrium (typical serosa): mesothelium and a little underlying loose connective tissue.<br />
<br />
<peir-vm>UAB-Histology-00278</peir-vm><br />
<br />
=== Slide 261, Uterus (H&E) ===<br />
<br />
Slide 261, Uterus (H&E), later proliferative phase, probably about days 10-12.<br />
<br />
Study the endometrium in comparison with slide 278.<br />
<br />
Note that the endometrium is a wider layer.<br />
<br />
Stroma is much less compact - more tissue fluid is present, fibroblasts are farther apart. Nearer the epithelium, stroma in places is beginning to have a spongy appearance.<br />
<br />
Glandular cells are larger, nuclei are large and vesicular, and epithelium appears pseudostratified. Secretion (glycogen, mucin) is beginning to accumulate at the bases of many cells. Small vacuolated areas represent the secretions that are removed during section preparation.<br />
<br />
Fibroblasts are seen more distinctly in the looser stroma; note their processes. Look for mitoses. Small lymphocytes are scattered throughout.<br />
<br />
Look for coiled arteries but they are not too prominent on this slide. Look for other small blood vessels.<br />
<br />
<peir-vm>UAB-Histology-00261</peir-vm><br />
<br />
=== Slide 262, Uterus (H&E) ===<br />
<br />
Slide 262, Uterus, (H&E) exhibits endometrium in a very late secretory phase or early premenstrual (probably days 24-26 of cycle; it is difficult to date precisely).<br />
<br />
Study the endometrium of this phase of the uterine cycle.<br />
<br />
Compare the width of the endometrium in this phase of the cycle with that in the previous slide.<br />
<br />
Note the characteristic large sacculated glands (“corkscrew appearance”). These are prominent throughout most of the functional zone. In the upper region of the functionalis zone (towards the surface) the glands have larger lumina but the sacculations in the walls are less.<br />
<br />
Note the position of the nuclei and the size of the glandular cells. Secretory material has moved from the infranuclear position to the supranuclear position, and some secretion has been liberated into the lumens of the glands. Therefore, the cells are smaller than in the earlier secretory stages, pseudostratification is much less apparent, and nuclei are basally located.<br />
<br />
Note areas of edema in the functional zone, but much of the excessive tissue fluid has already been resorbed.<br />
<br />
Note now the large size of the coiled arteries and their extent halfway or more upward into the functional zone.<br />
<br />
Observe the increased vascularity of capillaries and venules, especially in the outer functional zone. Some may already have ruptured.<br />
<br />
The surface epithelium is still intact.<br />
<br />
Note the myometrium and its blood vessels. Perimetrium is not present.<br />
<br />
<peir-vm>UAB-Histology-00262</peir-vm><br />
<br />
=== Slide 281, Cervix and OS Cervix, one wall (H&E) ===<br />
<br />
Slide shows endocervical epithelium and glands. The plane of section missed the junctional zone between endocervix and os cervix.<br />
<br />
Locate the os cervix (portio vaginalis) which is lined with stratified squamous epithelium. It can be seen grossly on the right margin of the section.<br />
<br />
Look along either surface of the section for cervical mucosa. The simple columnar lining epithelium consists of tall columnar cells, mucus-secreting; the luminal margin of the cells often appears indistinct or ragged. Note the Nabothian cyst (a cyst of a mucous gland of the cervix).<br />
<br />
The surface epithelium continues down to line the simple branched tubular mucus-secreting cervical glands.<br />
<br />
The lamina propria is no longer a primitive connective tissue as in the uterine endometrium.<br />
<br />
The mucosa is often folded, forming plicae palmatae.<br />
<br />
<peir-vm>UAB-Histology-00281</peir-vm><br />
<br />
== Vagina ==<br />
<br />
The vagina is a thick-walled fibromuscular tube that connects the uterus with the exterior and serves as a cavity for the reception of the penis at coitus and as a birth canal at the time of parturition.<br />
<br />
=== Slide 266, Vagina (H&E) ===<br />
<br />
The wall of the vagina consists of a mucosa, a muscularis, and a broad fibrosa that connects it to adjacent structures. The mucosa is thrown into broad folds (rugae) which are gross structures, not demonstrable in a small piece of tissue used for microscopic slides.<br />
<br />
Mucosa<br />
<br />
The epithelium is non-cornified stratified squamous. Note the stratum basale, the stratum spinosum, and the stratum corneum, so-called even though it is not cornified. The cells that appear empty contain glycogen and mucin, both of which are removed during routine section preparation.<br />
<br />
The broad areas of epithelium are tangential sections. Cross-sections of connective tissue papillae may be seen within them.<br />
<br />
Note connective tissue papillae projecting into the epithelium from the lamina propria. These are characteristic of most stratified squamous epithelia.<br />
<br />
The lamina propria is a broad zone of highly vascularized connective tissue, with abundant elastic fibers, extending to the muscularis. The elastic fibers may be seen as fine homogenous threads. (There is no muscularis mucosae or submucosa.) Note numerous small blood vessels and nerves. In many of the vessels, the endothelial cells (nuclei) are hypertrophied - not a normal condition.<br />
<br />
Scattered lymphocytes and plasma cells are seen throughout the mucosa. Lymphocytes may aggregate just below the epithelium to form diffuse lymphatic tissue or an occasional small nodule. Lymphocytes may penetrate the epithelium to migrate toward its surface.<br />
<br />
The muscularis, mostly arranged longitudinally, appears as bundles of smooth muscle interspersed with connective tissue rich in elastic fibers which may be seen as thin, homogenous threads. Larger blood vessels, as well as small ones, are found in the deep muscularis or fibrosa.<br />
<br />
The fibrosa is loose connective tissue. It should have some adipose tissue and nerves.<br />
<br />
<peir-vm>UAB-Histology-00266</peir-vm><br />
<br />
=== Slide 265, Vagina (Masson) ===<br />
<br />
Identify the regions of the wall and their component parts as in slide 266.<br />
<br />
Muscle and connective tissue are easily differentiated with Masson’s; they stain red and blue respectively. All nuclei stain red, as do erythrocytes. Elastic fibers are not distinguishable.<br />
<br />
The vascularity of the lamina propria is emphasized, with many of the venules congested.<br />
<br />
The large amount of connective tissue between the muscle bundles is well demonstrated.<br />
<br />
Lightly staining nerves occur among the muscle bundles and in the fibrosa.<br />
<br />
<peir-vm>UAB-Histology-00265</peir-vm><br />
<br />
== Placenta And Umbilical Cord ==<br />
<br />
Slides: 275, 264, 273, 274, 279, 280.<br />
<br />
=== Slide 275, Chorionic Villi (H&E) ===<br />
<br />
This is a section of a small part of a fetal placenta of a very early pregnancy, showing chorionic villi and the surrounding maternal blood spaces. Some slides have a strip of chorionic plate across the upper margin of the section.<br />
<br />
Chorionic plate<br />
<br />
The greater part of the plate is chorion, composed of a mass of embryonic connective tissue (large fibroblasts, fine collagenous fibers, abundant ground substance), covered on its lower surface by a double layer of epithelial cells: the cytotrophoblast adjacent to the connective tissue, and the syntrophoblast (syncytial trophoblast) on the free surface, bordering on maternal blood spaces.<br />
<br />
Cells of the syntrophoblast do not show cell boundaries. Ragged cell surfaces indicate microvilli. Cells of the cytotrophoblast supposedly show cell boundaries but they are not readily seen here. They divide to form syntrophoblast.<br />
<br />
Note blood vessels in the connective tissue (branches of umbilical vessels) containing nucleated fetal red blood corpuscles.<br />
<br />
The small zone of looser connective tissue in the upper part of the chorionic plate is part of the amnion. The cuboidal surface epithelium has been torn off.<br />
<br />
Chorionic villi. The villi are outgrowths from the chorion, having the same structure as the chorion. They increase in size and branch repeatedly as they invade the maternal blood spaces. The initial larger villi will become the anchoring villi that will penetrate the endometrium (decidua basalis) to anchor the fetal placenta. Smaller villi sprout off the anchoring villi.<br />
<br />
Note that the villi vary in size. The largest ones are potential anchoring villi. Others are floating villi; their free ends are in the blood spaces.<br />
<br />
Each villus has a core of embryonic connective tissue, branches of umbilical vessels (sparse in this early placenta), and a covering of inner cytotrophoblast and superficial syntrophoblast.<br />
<br />
<peir-vm>UAB-Histology-00275</peir-vm><br />
<br />
=== Slide 264, Uterus and Placenta from a later stage of pregnancy (PASH) === <br />
<br />
Look at the fetal placenta.<br />
<br />
Villi are larger and more numerous than in slide 275, stroma is generally more compact with more collagenous fibers (still fine) and abundant fibroblasts.<br />
<br />
Blood vessels in the villi are more numerous. Capillaries and little venules are peripherally located close to the trophoblast cells, although this may not be obvious due to plane of sections. Note that now red blood corpuscles are not nucleated.<br />
<br />
Syntrophoblast and cytotrophoblast are still present but cytotrophoblast is incomplete in many areas. (It will disappear entirely by late pregnancy.)<br />
<br />
Look for macrophages (Hofbauer cells) in the stroma of the villi - large rounded cells whose cytoplasm may have small vacuoles and/or PAS positive granules.<br />
<br />
Look for syncytial knots on the surface of villi or in the intervillous spaces. These are groups of syntrophoblast cells that detach from the villi and float freely in the spaces; progressively more are formed toward term.<br />
<br />
Look for very small deposits of fibrinoid, on or in the villi or in the intervillous spaces, a non-cellular, homogenous, proteinaceous material associated with transplantation immunity to protect the fetus.<br />
<br />
Maternal placenta (decidua basalis) and uterus. The decidua basalis is the name given to the endometrium that underlies the villi of the fetal placenta. Some villi (anchoring villi) penetrate the decidua basalis (endometrium) for varying distances. In doing so, part of the surface of the endometrium has been eroded and destroyed (surface epithelium is missing).<br />
<br />
Look for anchoring villi attaching to the decidua basalis. Note larger fibrinoid deposits and aggregations of syncytial knots in this region.<br />
<br />
In the decidua basalis, note the vast numbers of large and smaller decidual cells with PAS- positive cytoplasm (are storing glycogen) and large, lightly staining nuclei. Cytoplasm of those with less glycogen stains faintly acidophilic or somewhat grayish. Decidual cells are derived from fibroblasts of the endometrium.<br />
<br />
A few glands are seen in the basal zone of the endometrium. They may be dilated, have very low epithelium or hypertrophied epithelium, and have lymphocytic infiltration surrounding some of them.<br />
<br />
Identify the myometrium and note the large size of the muscle fibers that hypertrophy greatly during pregnancy.<br />
<br />
<peir-vm>UAB-Histology-00264</peir-vm><br />
<br />
=== Slide 280. Uterus and Placenta near term (H&E) ===<br />
<br />
Fetal placenta. Proliferation of villi has continued to increase during pregnancy.<br />
<br />
Note the great number of chorionic villi, practically filling the maternal blood spaces. The anchoring villi have become very large. The connective tissue in the core is fibrous, but embryonic connective tissue has persisted at the periphery. The larger blood vessels course in these villi. Observe the variation in size of the floating villi, which continue to form throughout pregnancy.<br />
<br />
In the villi, note further compactness of stroma, areas of more dense collagenous fibers, more capillaries, and venules close to the trophoblast.<br />
<br />
Look for macrophages (Hofbauer cells) in the stroma of the villi. With H&E, the cytoplasm is finely vacuolated.<br />
<br />
Syntrophoblasts still cover the surface of the villi. Cytotrophoblasts have generally disappeared.<br />
<br />
Note increased number of syncytial knots and much fibrinoid material. Knots are seen deep in the endometrium; they appear as darkly stained groups of pyknotic nuclei.<br />
<br />
The maternal placenta (decidua basalis).<br />
<br />
Again note the placental villi anchoring into the endometrium.<br />
<br />
Decidual cells are still present in the endometrium but many have “used up” their glycogen and are reverting to fibroblasts. Lymphocytic infiltration is seen in places. Much fibrinoid is present.<br />
<br />
Uterine glands, whose basal portions had remained inactive, are proliferating and regenerating. Some appear cystic.<br />
<br />
Uterine Muscularis.<br />
<br />
The three layers are not readily identified, but note again the large size of the fibers.<br />
<br />
Note the huge multinucleated giant cells in the deep endometrium and especially in the muscularis. They are thought to be of trophoblastic origin (perhaps differentiated from but not to be confused with syncytial knots).<br />
<br />
<peir-vm>UAB-Histology-00280</peir-vm><br />
<br />
=== Slide 279. Placenta at term (H&E) ===<br />
<br />
These slides are from a “fresh” placenta immediately after parturition; thus very little postmortem change is present and structures are seen distinctly.<br />
<br />
Go over the fetal placenta as in slide 280. Numerous red blood corpuscles are present in the maternal blood spaces, probably due to rupture of blood vessels during parturition.<br />
<br />
Note the tremendous vascularity of the placental villi, apparent here because of the fresh condition of the tissues; note also the great number of syncytial knots.<br />
<br />
A fragment of decidua basalis may be present (left end of the section in the field). Anchoring villi are seen and large decidual cells may still be present.<br />
<br />
<peir-vm>UAB-Histology-00279</peir-vm><br />
<br />
=== Slide 274, Placenta at term (PASH) ===<br />
<br />
This tissue is from the same placenta used for making slides 279 and 273. Look at the slide to see how term structures stain with PASH.<br />
<br />
Basement membranes are prominent under the syntrophoblast and under endothelium of the blood vessels. Note also that blood vessels are more numerous in these villi than in those of slide 280, are also congested which may be the cause of their large size.<br />
<br />
Areas of decidua basalis are present.<br />
<br />
<peir-vm>UAB-Histology-00274</peir-vm><br />
<br />
=== Slide 273, Placenta, term (Masson) ===<br />
<br />
This tissue is from the same placenta as used for making slides 274 and 279.<br />
<br />
Identify the structures as seen with this stain. Connective tissue elements are blue, nuclei are reddish or indistinct, and the cytoplasm varies. <br />
<br />
This section shows the chorionic plate at the right (in the field).<br />
<br />
The outer “membrane” is the amnion, consisting of a layer of cuboidal or low columnar epithelium and a thin layer of connective tissue. It is mechanically separated from the underlying chorion.<br />
<br />
The chorion consists of a layer of connective tissue covered by syncytial trophoblast that is now mostly fibrinoid.<br />
<br />
Two main umbilical vessels and smaller branches are passing through the chorionic plate.<br />
<br />
<peir-vm>UAB-Histology-00273</peir-vm><br />
<br />
== Umbilical Cord ==<br />
<br />
=== Slide 287, Umbilical Cords (H&E) ===<br />
<br />
Slide 287, Umbilical Cords (H&E), is from an early pregnancy and from late in pregnancy.<br />
<br />
The early pregnancy umbilical cord is on the left. The two umbilical arteries and the umbilical vein look generally similar because of the atypical large amount of muscle in the wall. An internal elastic membrane is lacking in the arteries. The diameter of the vein is greater than that of the artery and the muscle is not quite as compactly arranged.<br />
<br />
The stroma of the cord is mucous connective tissue - embryonic connective tissue with a mucoid ground substance (Wharton’s jelly) which is removed in section preparation. Note the fine collagenous fibers and the large branched fibroblasts.<br />
<br />
Covering the cord is simple squamous or simple cuboidal epithelium, part of the amnion.<br />
<br />
<peir-vm>UAB-Histology-00287</peir-vm><br />
<br />
=== Slides 287 (tissue on right) and Slide 277, umbilical cord at term (H&E) ===<br />
<br />
In this fully developed placenta, the atypical structure of the arteries is well shown - a wide inner layer of longitudinally arranged muscle and a thick outer circular layer. Postmortem contraction causes collapse of the vessels. The vein has some inner longitudinal muscle; most of it is outer circular. Reticular fibers between muscle fibers are seen with H&E (due to postmortem shrinkage of muscle fibers). The small vacuoles are probably early degenerative changes.<br />
<br />
Collagenous fibers in the stroma are somewhat heavier than in the earlier cord but are not mature fibers. Mucous connective tissue retains its embryonic nature; note that fibroblasts are still large branched cells.<br />
<br />
Neutrophils are invading some areas of the stroma (lower field especially), also related to breakdown of the tissues.<br />
<br />
Epithelium of the amnion surrounds the cord.<br />
<br />
==== Slide 287, Umbilical Cord at term (tissue on right) (H&E) ====<br />
<peir-vm>UAB-Histology-00287</peir-vm><br />
==== Slide 277, Umbilical Cord at term (H&E) ====<br />
<peir-vm>UAB-Histology-00277</peir-vm><br />
<br />
{{Template:Histologic}}<br />
<br />
[[Category:Histologic]]</div>Matthew Andersonhttps://peir.path.uab.edu/index.php?title=Histologic:Chapter_16&diff=3251Histologic:Chapter 162014-07-18T19:09:17Z<p>Matthew Anderson: /* Prostate Gland */</p>
<hr />
<div>== Introduction ==<br />
<br />
The components of the male reproductive system include the testes, the genital ducts, the accessory glands, and the penis.<br />
<br />
== The Testis ==<br />
[[File:HistologicChapter16Testis.jpg|thumb|200px|Testis]]<br />
The testis functions as a cytogenic gland in that it produces spermatozoa and as an endocrine gland which produces the hormone testosterone. This hormone is essential for the proper development and maintenance of the accessory sexual organs, particularly the genital ducts and the accessory glands.<br />
<br />
The two ovoid testes lie in the scrotum. Each testis is covered by three tunics.<br />
<br />
*A prominent, tough, fibrous layer of connective tissue called the tunica albuginea forms the middle tunic.<br />
<br />
*Investing the tunica albuginea is a layer of squamous cells and a thin layer of loose connective tissue, the tunica vaginalis, which represents a serous lining of peritoneum “trapped” by the descended testis. This tunic is lacking on the posterior wall of the testis.<br />
<br />
*Internal to the tunica albuginea is a thin layer of loose, highly vascular connective tissue called the tunica vasculosa.<br />
<br />
The testis is divided into about 250 anastomosing, pyramidal-shaped lobules by delicate connective tissue septa, the septulae testis. The septa radiate from the mediastinum into the testis. Within the testicular lobules occur from one to four convoluted seminiferous tubules where spermatozoa are produced. <br />
<br />
The stroma of the testis lies between the seminiferous tubules. In addition to the usual connective tissue cells and collagenous fibers found in loose, vascular connective tissue, the stroma also contains endocrine tissue consisting of the interstitial cells (cells of Leydig). These cells produce the androgenic steroid hormone testosterone. Production of testosterone is stimulated by luteinizing hormone (LH = interstitial cell stimulating hormone, ICSH) produced by basophils of the anterior pituitary gland. Interstitial cells are polyhedral shaped cells (14 to 21 μm in diameter) with a large, rounded, sometimes wrinkled nucleus, and an acidophilic cytoplasm. The cytoplasm, in addition to the usual organelles, also contains a vast amount of smooth endoplasmic reticulum and mitochondria containing tubular cristae. These organelles are characteristic of cells which produce steroid hormones. Another cytoplasmic characteristic of interstitial cells are protein crystals (of Reinke) that vary in size, form and frequency of occurrence. The significance of these crystals is not clear.<br />
<br />
A seminiferous tubule has a highly complex stratified epithelium consisting of spermatogenic cells and supporting cells (= sustentacular or Sertoli cells). External to the basement membrane on which the epithelium rests is a tunic of fibroelastic tissue. The supporting cells are tall, irregular columnar cells extending from the basement membrane to the lumen of the seminiferous tubule. On the lateral and apical surfaces, numerous recesses are formed by the plasma membrane which “indents” the cytoplasm. Within these recesses or depressions lie developing spermatogenic cells. The elaborate shapes of the supporting cells are difficult to see unless the testis has been prepared by a silver technique which demonstrates the cell boundaries. The large nuclei (9 to 12 μm diameter) of supporting cells have a variable position ranging from the basal zone to the mid- region of the cell. The nucleus is usually ovoid, stains palely, and shows an unusual tripartite nucleolus possessing a central acidophilic mass flanked by two basophilic masses. The nuclear membrane is frequently folded or longitudinally indented. The presence of moderate amounts of smooth endoplasmic reticulum and other features characteristic of steroid producing cells have led to suggestions that the supporting cells may produce steroid hormones. The major role of these cells is in mechanical support, protection, and perhaps nourishment of the developing germ cells.<br />
<br />
=== Slide 227, Testis (H&E) === <br />
<br />
Scan this slide to observe:<br />
<br />
Section of testis containing sections of seminiferous tubules. Note the dense tunica albuginea, the tunica vasculosa, the septula testis and the connective tissue stroma or interstitial tissue.<br />
<br />
Identify the mediastinum testis containing the irregular channels of the rete testis. <br />
<br />
A portion of the epididymis is present (the mass of tissue at one end) and can be seen containing efferent ducts and sections of the ductus epididymis. The former are in the uppermost area, the latter in the lowermost region.<br />
<br />
Note the numerous blood vessels, nerves and abundance of connective tissue fibers and adipose tissue adjacent to the mediastinum and epididymis.<br />
<br />
Study the normal seminiferous tubules. Locate the three layers that constitute the wall of a tubule. These are:<br />
<br />
*An outermost layer of fibroelastic connective tissue.<br />
*A basement membrane on which the spermatogonial and supporting cells rest.<br />
*The complex stratified epithelium where spermatogenesis occurs.<br />
<br />
The three layers may be seen more easily on slide 228, Testis (Masson) where the basement membrane is stained blue.<br />
<br />
On slide 227, 228 and 230 identify the interstitial cells in the stromal tissue lying in angles between the seminiferous tubules. Interstitial cells are polyhedral in shape, have an acidophilic cytoplasm, and possess a rounded nucleus that usually contains one or two prominent nucleoli. The cytoplasm may be vacuolated where lipid droplets were dissolved away and an occasional cell may contain golden brown deposits of lipochrome pigment.<br />
<br />
On the same slides, identify the supporting cells (Sertoli cells) within the stratified epithelium of the seminiferous tubules. Their cell boundaries will not be seen, but one usually can identify the nuclei of these tall columnar cells. The ovoid nucleus stains palely, contains a nucleolus and will occupy a variable position ranging from near the basement membrane to the middle of the cell.<br />
<br />
Within the seminiferous tubules of slide 230 identify as many of the spermatogenic cells as possible. <br />
<br />
<peir-vm>UAB-Histology-00227</peir-vm><br />
<br />
==== Slide 228, Testis (Masson) ====<br />
<peir-vm>UAB-Histology-00228</peir-vm><br />
==== Slide 230, Testis ====<br />
<peir-vm>UAB-Histology-00230</peir-vm><br />
<br />
== Genital Ducts ==<br />
<br />
Straight tubules. On slide 227, Testis (H&E) identify the straight tubules located in a narrow region between the ends of the seminiferous tubules and the rete testis. The simple columnar epithelial cells, which line the initial segment of the straight tubules, resemble supporting cells. Near the rete testis the cells shorten to become cuboidal. These tubules have a uniformly narrow diameter.<br />
<br />
Rete testis. The rete testis is located in the connective tissue of the mediastinum testis. It is that portion of the genital ducts which unites the straight tubules (tubuli recti) with the efferent ducts. The rete testis is essentially a system of anastomosing channels of epithelial lined spaces within connective tissue. As such the epithelium of these irregular spaces consists of low simple cuboidal to simple squamous cells resting on a basement membrane. A single cilium may occur on some of the cells. (Not seen on our slide.) A distinct lamina propria and muscularis are lacking. On slides 227 and 230 locate and study the rete testis in the dense connective tissue of the mediastinum. On these slides, its extent varies from extensive to virtually absent.<br />
<br />
Efferent ducts. Efferent ducts (ductuli efferentes). About twelve to fifteen ductules (0.6 mm in diameter, 4 to 6 mm long) called efferent ducts unite the rete testis with the ductus epididymis. The ductules emerge from the mediastinum to the surface of the testis where they form cone-shaped coils that constitute much of the head of the epididymis. The efferent ducts consist of an epithelium resting on a thin basement membrane and some circularly oriented smooth muscle fibers embedded within the connective tissue surrounding the ductules.<br />
<br />
On slide 227, Testis (H&E), and slide 230, Testis, (H&E) locate the efferent ducts in the epididymal region by the scalloped or undulated appearance of the epithelium. They appear in the lower right field on slide 227 and in the upper right field on slide 230. The epithelium is pseudostratified with small basal cells near the basement membrane and larger columnar or cuboidal surface cells. This gives the luminal surface of the ducts an irregular contour. The columnar cells are usually ciliated, whereas microvilli extend into the lumen from the cuboidal cells. (Cilia and microvilli are difficult to see on our slide.) Transport of sperm to the ductus epididymis is facilitated by the beating of the cilia. Motile cilia in the male genital ducts are found here and in the rete testis. The microvilli probably serve an absorptive function. Pigment granules and pale secretion granules may sometimes be seen in both types of surface cells of the ducts. Also, clear areas occur within the cells where fat has been dissolved away. On the upper right edge of slide 230 is a long, cystic tubule, probably an efferent duct that became obstructed.<br />
<br />
Ductus epididymis. The epididymis lies on the posterior side of the testis. The ductus epididymis consists of a highly coiled duct (or tube) five to six meters in length, surrounded by smooth muscle and connective tissue. It occupies the body and the tail of the epididymis. The ductus epididymis unites proximally with the efferent ducts and distally with the ductus deferens. The duct is lined with a pseudostratified columnar epithelium consisting of tall columnar cells and smaller rounded basal cells. Large, nonmotile, branching microvilli called stereocilia extend from the apices of the columnar cells. Within the cytoplasm of these cells are secretory granules or vacuoles and pigment. Surrounding the epithelium is a thin lamina propria encircled by a very thin layer of smooth muscle. Outside the smooth muscle lies loose to compact connective tissue that forms the interstitium or stroma of the epididymis.<br />
<br />
=== Slide 229, Ductus Epididymis (Masson) ===<br />
<br />
Observe:<br />
<br />
That numerous coils of the duct have been sectioned in various planes.<br />
<br />
The relatively smooth lumen of the duct, owing to the uniform thickness of the epithelium and the stereocilia extending into the lumen.<br />
<br />
The sperm stored within the lumen.<br />
<br />
The scant amount of stromal connective tissue and smooth muscle surrounding the various coils of the duct.<br />
<br />
<peir-vm>UAB-Histology-00229</peir-vm><br />
<br />
=== Slide 6, Ductus Epididymis (H&E) ===<br />
<br />
Note especially the pseudostratified columnar epithelium possessing tall stereocilia.<br />
<br />
<peir-vm>UAB-Histology-00006</peir-vm><br />
<br />
=== Slide 230, Testis (H&E) ===<br />
<br />
Study slide 230, Testis (H&E) for comparison of efferent ducts and ductus epididymis.<br />
<br />
Locate the numerous sections of the ductus epididymis (lower right field in both slides). Again, note the relatively smooth outline of the luminal surface of the ductus epididymis. Compare the appearance of this duct with the scalloped appearance of the efferent ducts previously studied on these slides (in the upper fields) especially on slide 230 where the latter are more numerous.<br />
<br />
Ductus deferens. During development the testis descends from its early position on the posterior abdominal wall into the pelvis, and later during the seventh month of fetal life, it passes through the inguinal canal into the scrotum. Upon descending, each testis “pulls along” its vessels, nerves and ducts (ductus deferens) with it. These structures constitute the spermatic cord. The components of the spermatic cord are surrounded by connective tissue layers (fascia of gross anatomy) and by a somewhat discontinuous, longitudinally oriented layer of striated muscle fibers of the cremaster muscle.<br />
<br />
The constituents of the spermatic cord are the:<br />
<br />
*ductus deferens<br />
*artery of the ductus deferens<br />
*testicular artery<br />
*cremasteric artery<br />
*pampiniform plexus of veins<br />
*lymphatic vessels<br />
*nerves of the testis and epididymis<br />
<br />
<peir-vm>UAB-Histology-00230</peir-vm><br />
<br />
=== Slide 232, Spermatic Cord (H&E) ===<br />
<br />
Scan the tissue to observe:<br />
<br />
*The large ductus deferens with its thick muscular coat.<br />
<br />
*The numerous veins which constitute the pampiniform plexus. Some of these veins have unusually thick muscular tunics and bundles of longitudinally oriented muscle in the adventitia (medium-sized veins). <br />
<br />
*Arteries<br />
<br />
*Nerves<br />
<br />
*Connective tissue fibers and adipose tissue of the fascial layers.<br />
<br />
<peir-vm>UAB-Histology-00232</peir-vm><br />
<br />
== Accessory Glands ==<br />
<br />
=== Prostate Gland ===<br />
[[File:HistologicChapter16Prostate.jpg|thumb|200px|Prostate]]<br />
The prostate gland is an accessory, unpaired sex gland of males that surrounds the urethra as it leaves the bladder. The prostate is an aggregation of 30 to 50 branched tubuloalveolar glands that secrete a milky fluid rich in citric acid and acid phosphatase. Grossly, the prostate gland has five lobes and is about one and a half inches in diameter. It is surrounded by a fibromuscular capsule.<br />
<br />
The individual glands making up the overall prostate are arranged into a mucosal, a submucosal, and a main group of glands. They lie embedded in a fibromuscular stroma. The prostatic urethra traverses the prostate gland from superior to inferior surfaces. On each side of the prostatic utricle (the male homologue to the vagina) are located the ejaculatory ducts which open into the prostatic urethra. The ejaculatory ducts and the prostatic utricle are located in the seminal colliculus, an elevated portion of the urethral crest. The urethral crest is a longitudinal ridge that forms the posterior wall of the prostatic urethra.<br />
<br />
==== Slide 123, Prostate (H&E) ====<br />
<br />
Study Slide 123, Prostate (H&E) which is a section of the prostate from a 26- year-old male. Under low power note the numerous glands surrounded by the fibromuscular stroma. These glands are from the main group of glands of the prostate. Study them for detail noting that:<br />
<br />
The epithelium is low pseudostratified, having columnar cells and basal cells resting on a thin basement membrane (not seen here). The apices of the columnar cells appear “washed out” (poorly stained) indicating that some of the secretory material has been lost in fixation and/or that the secretory droplets stain poorly with H&E. The apices of most of the secretory cells stain positively with lipid stains.<br />
<br />
The epithelium shows numerous folds. Some of the folds have been sectioned tangentially and here the epithelium appears stratified. In other areas, the folds are cut through and appear as small “isolated islands” of epithelium.<br />
<br />
Eosinophilic prostatic concretions (corpora amylacea) can be seen within the lumina of the glands. These rounded bodies increase with age following adulthood. They contain carbohydrate and protein and may become large enough to occlude the lumens of the glands. When calcified they are called calculi.<br />
<br />
Study the abundant fibromuscular stroma making up about one-fourth to one-third of the gland. Strands of smooth muscle varying in thickness are intermixed with collagenous and elastic fibers. The muscle does not appear to have definite orientation or layers. This fibromuscular stroma is a distinctive feature of the prostate.<br />
<br />
<peir-vm>UAB-Histology-00123</peir-vm><br />
<br />
==== Slide 124, Prostatic Urethra (H&E) ====<br />
<br />
On slide 124, Prostatic Urethra (H&E), the general distribution of the somewhat concentrically arranged mucosal, submucosal and main prostatic glands can be studied. Identify these glands according to their locations.<br />
<br />
The mucosal glands are smallest and are periurethral in position (next to the urethra). Their ducts open at various points into the urethra. (These are small, few in number and may be absent on your section.)<br />
<br />
The submucosal glands are immediately peripheral to the mucosal ones, and the main glands which are largest and most numerous, lie to the outside of the submucosal glands on the periphery of the section. The ducts of the submucosal and main glands open into the urethral sinuses.<br />
<br />
Abnormalities are present. Some of the main glands show cystic dilations.<br />
<br />
The epithelium of these cystic glands is less folded than in the normal glands and in some regions appears to be squamous and less secretory than normal. Some glands may show lymphocytic infiltration. Others have stratified epithelium (hyperplasia).<br />
<br />
Study the prostatic urethra, a U-shaped groove in the prostate, and the urethral crest, a longitudinal ridge that forms the posterior wall of the prostatic urethra. The posterolateral portions of the urethra on each side of the urethral crest are the urethral sinuses. It is here where the ducts of the submucosal and main glands empty secretions into the urethra.<br />
<br />
Note the epithelium of the urethra. It is usually classified as transitional epithelium but patches of stratified columnar epithelium may be present.<br />
<br />
Most slides do not have ejaculatory ducts or the prostatic utricle since the section was taken through the prostate superior to the entrance of these structures into the urethra, but parts of these two structures may be present. The part of the urethral crest in which the prostatic utricle is located is the colliculus seminalis.<br />
<br />
Observe the periurethral vascular supply and the venous plexuses in the urethral crest.<br />
<br />
<peir-vm>UAB-Histology-00124</peir-vm><br />
<br />
=== Seminal Vesicles ===<br />
<br />
The seminal vesicles are paired saccular organs each in the form of a convoluted tube. They lie posterior to the prostate and their secretions, rich in fructose, enter the ejaculatory ducts just below the ampulla of the ductus deferens. The three layers of the gland are a mucosa, a muscularis and an adventitia (= fibrosa). The single lumen is irregular and branching with numerous lateral outpocketings.<br />
<br />
==== Slide 237, Seminal Vesicle (H&E) ====<br />
<br />
Observe that the gland appears to possess numerous lumina. Actually only one continuous cavity is present, but when the numerous convolutions of the gland are cut in one plane, separate cavities appear to be present.<br />
<br />
Note the complicated folding of the mucosa in which thin primary folds often exhibit secondary and tertiary branching.<br />
<br />
The muscularis contains an inner circular and an outer longitudinal layer of smooth muscle; two layers are not easily distinguishable in a section. <br />
<br />
The adventitia or fibrosa is rich in elastic fibers. It contains large blood vessels, nerves, and blends with other connective tissue surrounding the gland. One or more ganglia may be present.<br />
<br />
With high power study the mucosa on slide 237. The epithelium may appear to be simple cuboidal or low columnar, but the presence of basal cells makes it a low pseudostratified epithelium. The lining cells are secretory. A few granules may be present, or vacuoles may occur where they were dissolved away. Look for yellow or brownish lipochrome pigment in the surface cells. This pigment gives a yellowish tinge to the viscid secretions coming from these glands. The pigment begins to appear at puberty and increases with age. Beneath the epithelium is a basement membrane and a thin lamina propria with abundant elastic fibers. <br />
<br />
<peir-vm>UAB-Histology-00237</peir-vm><br />
<br />
=== Bulbourethral Gland ===<br />
<br />
==== Slide 238, Bulbourethral Gland (Masson) ====<br />
<br />
Scan Slide 238, Bulbourethral gland (Masson) to observe that:<br />
<br />
The irregular lobules of this compound tubuloalveolar gland are separated from each other by connective tissue septa that extend inward from a thin capsule.<br />
<br />
At the periphery of the gland and also in the connective tissue septa between some of the lobules can be seen skeletal muscle fibers.<br />
<br />
Interlobular excretory ducts lie within some of the larger connective tissue septa. (See e below)<br />
<br />
With high power study the parenchyma consisting of pale secretory cells, usually cuboidal to columnar in shape. They resemble mucous cells. The nucleus tends to be flattened at the base of the cells; however, some are rounded, others are oval and vertically oriented. The varying shapes of the nuclei probably indicate different states of secretory activity exhibited by the cells at the time of fixation. A mucus-like discharge from these glands lubricates the urethra during sexual simulation.<br />
<br />
In the smaller ducts of the bulbourethral gland the epithelium is simple and quite variable ranging from low cuboidal to columnar. The large excretory ducts are lined by stratified columnar epithelium that may contain patches of secreting cells. Smooth muscle fibers can usually be found among the connective tissue fibers surrounding these ducts and also in other regions of the connective tissue septa.<br />
<br />
<peir-vm>UAB-Histology-00238</peir-vm><br />
<br />
== Penis ==<br />
<br />
=== Slide 284, Penis (H&E) ===<br />
<br />
The penis is composed of erectile tissue and contains the section of penile urethra. The erectile tissue is composed of two dorsal cylinders (corpora cavernosa) and a smaller central ventral cylinder (corpus spongiosum) through which the penile urethra runs. These cylinders are each surrounded by a dense fibrocollagenous sheath, the tunica albuginea. The erectile tissues are essentially interconnecting vascular spaces which are empty when the penis is flaccid but which become engorged with blood during an erection. <br />
<br />
The blood supply to the penis is provided by the dorsal and the deep arteries. From the deep arteries arise arteries supplying the tunica albuginea, and the helicine arteries, which supply the erectile tissue. The helicine arteries form convoluted vessels in the flaccid penis but during erection they straighten and dilate, filling the corpora with blood. This filling effect is partly due to closure of the arteriovenous shunts existing between the helicine arteries and deep veins, which constitute the normal route of helicine artery blood flow in the flaccid state. Parasympathetic nerve discharges cause the closure, leading to diversion of the helicine artery blood into the cavernous spaces, while increased pressure in the corpora compresses the thin-walled veins, preventing emptying. After ejaculation the parasympathetic stimulation ceases, the arteriovenous shunts open and blood passes from the corpora into the veins.<br />
<br />
At the distal end of the penis the corpus spongiosum terminates on the glans penis, which is covered with non-keratinizing squamous epithelium containing sebaceous glands. The penile urethra opens to the exterior at the meatus at the centre of the glans penis<br />
<br />
For most of its length the penile urethra is lined by non-secreting columnar epithelium into which small mucus glands embedded in the corpus spongiosum drain. Within the glans penis, however, the urethra dilates (navicular fossa) and becomes lined by non-keratinizing stratified squamous epithelium identical to that covering the glans.<br />
<br />
<peir-vm>UAB-Histology-00284</peir-vm><br />
<br />
{{Template:Histologic}}<br />
<br />
[[Category:Histologic]]</div>Matthew Andersonhttps://peir.path.uab.edu/index.php?title=File:HistologicChapter16Prostate.jpg&diff=3250File:HistologicChapter16Prostate.jpg2014-07-18T19:08:59Z<p>Matthew Anderson: </p>
<hr />
<div></div>Matthew Andersonhttps://peir.path.uab.edu/index.php?title=Histologic:Chapter_16&diff=3249Histologic:Chapter 162014-07-18T19:07:46Z<p>Matthew Anderson: /* The Testis */</p>
<hr />
<div>== Introduction ==<br />
<br />
The components of the male reproductive system include the testes, the genital ducts, the accessory glands, and the penis.<br />
<br />
== The Testis ==<br />
[[File:HistologicChapter16Testis.jpg|thumb|200px|Testis]]<br />
The testis functions as a cytogenic gland in that it produces spermatozoa and as an endocrine gland which produces the hormone testosterone. This hormone is essential for the proper development and maintenance of the accessory sexual organs, particularly the genital ducts and the accessory glands.<br />
<br />
The two ovoid testes lie in the scrotum. Each testis is covered by three tunics.<br />
<br />
*A prominent, tough, fibrous layer of connective tissue called the tunica albuginea forms the middle tunic.<br />
<br />
*Investing the tunica albuginea is a layer of squamous cells and a thin layer of loose connective tissue, the tunica vaginalis, which represents a serous lining of peritoneum “trapped” by the descended testis. This tunic is lacking on the posterior wall of the testis.<br />
<br />
*Internal to the tunica albuginea is a thin layer of loose, highly vascular connective tissue called the tunica vasculosa.<br />
<br />
The testis is divided into about 250 anastomosing, pyramidal-shaped lobules by delicate connective tissue septa, the septulae testis. The septa radiate from the mediastinum into the testis. Within the testicular lobules occur from one to four convoluted seminiferous tubules where spermatozoa are produced. <br />
<br />
The stroma of the testis lies between the seminiferous tubules. In addition to the usual connective tissue cells and collagenous fibers found in loose, vascular connective tissue, the stroma also contains endocrine tissue consisting of the interstitial cells (cells of Leydig). These cells produce the androgenic steroid hormone testosterone. Production of testosterone is stimulated by luteinizing hormone (LH = interstitial cell stimulating hormone, ICSH) produced by basophils of the anterior pituitary gland. Interstitial cells are polyhedral shaped cells (14 to 21 μm in diameter) with a large, rounded, sometimes wrinkled nucleus, and an acidophilic cytoplasm. The cytoplasm, in addition to the usual organelles, also contains a vast amount of smooth endoplasmic reticulum and mitochondria containing tubular cristae. These organelles are characteristic of cells which produce steroid hormones. Another cytoplasmic characteristic of interstitial cells are protein crystals (of Reinke) that vary in size, form and frequency of occurrence. The significance of these crystals is not clear.<br />
<br />
A seminiferous tubule has a highly complex stratified epithelium consisting of spermatogenic cells and supporting cells (= sustentacular or Sertoli cells). External to the basement membrane on which the epithelium rests is a tunic of fibroelastic tissue. The supporting cells are tall, irregular columnar cells extending from the basement membrane to the lumen of the seminiferous tubule. On the lateral and apical surfaces, numerous recesses are formed by the plasma membrane which “indents” the cytoplasm. Within these recesses or depressions lie developing spermatogenic cells. The elaborate shapes of the supporting cells are difficult to see unless the testis has been prepared by a silver technique which demonstrates the cell boundaries. The large nuclei (9 to 12 μm diameter) of supporting cells have a variable position ranging from the basal zone to the mid- region of the cell. The nucleus is usually ovoid, stains palely, and shows an unusual tripartite nucleolus possessing a central acidophilic mass flanked by two basophilic masses. The nuclear membrane is frequently folded or longitudinally indented. The presence of moderate amounts of smooth endoplasmic reticulum and other features characteristic of steroid producing cells have led to suggestions that the supporting cells may produce steroid hormones. The major role of these cells is in mechanical support, protection, and perhaps nourishment of the developing germ cells.<br />
<br />
=== Slide 227, Testis (H&E) === <br />
<br />
Scan this slide to observe:<br />
<br />
Section of testis containing sections of seminiferous tubules. Note the dense tunica albuginea, the tunica vasculosa, the septula testis and the connective tissue stroma or interstitial tissue.<br />
<br />
Identify the mediastinum testis containing the irregular channels of the rete testis. <br />
<br />
A portion of the epididymis is present (the mass of tissue at one end) and can be seen containing efferent ducts and sections of the ductus epididymis. The former are in the uppermost area, the latter in the lowermost region.<br />
<br />
Note the numerous blood vessels, nerves and abundance of connective tissue fibers and adipose tissue adjacent to the mediastinum and epididymis.<br />
<br />
Study the normal seminiferous tubules. Locate the three layers that constitute the wall of a tubule. These are:<br />
<br />
*An outermost layer of fibroelastic connective tissue.<br />
*A basement membrane on which the spermatogonial and supporting cells rest.<br />
*The complex stratified epithelium where spermatogenesis occurs.<br />
<br />
The three layers may be seen more easily on slide 228, Testis (Masson) where the basement membrane is stained blue.<br />
<br />
On slide 227, 228 and 230 identify the interstitial cells in the stromal tissue lying in angles between the seminiferous tubules. Interstitial cells are polyhedral in shape, have an acidophilic cytoplasm, and possess a rounded nucleus that usually contains one or two prominent nucleoli. The cytoplasm may be vacuolated where lipid droplets were dissolved away and an occasional cell may contain golden brown deposits of lipochrome pigment.<br />
<br />
On the same slides, identify the supporting cells (Sertoli cells) within the stratified epithelium of the seminiferous tubules. Their cell boundaries will not be seen, but one usually can identify the nuclei of these tall columnar cells. The ovoid nucleus stains palely, contains a nucleolus and will occupy a variable position ranging from near the basement membrane to the middle of the cell.<br />
<br />
Within the seminiferous tubules of slide 230 identify as many of the spermatogenic cells as possible. <br />
<br />
<peir-vm>UAB-Histology-00227</peir-vm><br />
<br />
==== Slide 228, Testis (Masson) ====<br />
<peir-vm>UAB-Histology-00228</peir-vm><br />
==== Slide 230, Testis ====<br />
<peir-vm>UAB-Histology-00230</peir-vm><br />
<br />
== Genital Ducts ==<br />
<br />
Straight tubules. On slide 227, Testis (H&E) identify the straight tubules located in a narrow region between the ends of the seminiferous tubules and the rete testis. The simple columnar epithelial cells, which line the initial segment of the straight tubules, resemble supporting cells. Near the rete testis the cells shorten to become cuboidal. These tubules have a uniformly narrow diameter.<br />
<br />
Rete testis. The rete testis is located in the connective tissue of the mediastinum testis. It is that portion of the genital ducts which unites the straight tubules (tubuli recti) with the efferent ducts. The rete testis is essentially a system of anastomosing channels of epithelial lined spaces within connective tissue. As such the epithelium of these irregular spaces consists of low simple cuboidal to simple squamous cells resting on a basement membrane. A single cilium may occur on some of the cells. (Not seen on our slide.) A distinct lamina propria and muscularis are lacking. On slides 227 and 230 locate and study the rete testis in the dense connective tissue of the mediastinum. On these slides, its extent varies from extensive to virtually absent.<br />
<br />
Efferent ducts. Efferent ducts (ductuli efferentes). About twelve to fifteen ductules (0.6 mm in diameter, 4 to 6 mm long) called efferent ducts unite the rete testis with the ductus epididymis. The ductules emerge from the mediastinum to the surface of the testis where they form cone-shaped coils that constitute much of the head of the epididymis. The efferent ducts consist of an epithelium resting on a thin basement membrane and some circularly oriented smooth muscle fibers embedded within the connective tissue surrounding the ductules.<br />
<br />
On slide 227, Testis (H&E), and slide 230, Testis, (H&E) locate the efferent ducts in the epididymal region by the scalloped or undulated appearance of the epithelium. They appear in the lower right field on slide 227 and in the upper right field on slide 230. The epithelium is pseudostratified with small basal cells near the basement membrane and larger columnar or cuboidal surface cells. This gives the luminal surface of the ducts an irregular contour. The columnar cells are usually ciliated, whereas microvilli extend into the lumen from the cuboidal cells. (Cilia and microvilli are difficult to see on our slide.) Transport of sperm to the ductus epididymis is facilitated by the beating of the cilia. Motile cilia in the male genital ducts are found here and in the rete testis. The microvilli probably serve an absorptive function. Pigment granules and pale secretion granules may sometimes be seen in both types of surface cells of the ducts. Also, clear areas occur within the cells where fat has been dissolved away. On the upper right edge of slide 230 is a long, cystic tubule, probably an efferent duct that became obstructed.<br />
<br />
Ductus epididymis. The epididymis lies on the posterior side of the testis. The ductus epididymis consists of a highly coiled duct (or tube) five to six meters in length, surrounded by smooth muscle and connective tissue. It occupies the body and the tail of the epididymis. The ductus epididymis unites proximally with the efferent ducts and distally with the ductus deferens. The duct is lined with a pseudostratified columnar epithelium consisting of tall columnar cells and smaller rounded basal cells. Large, nonmotile, branching microvilli called stereocilia extend from the apices of the columnar cells. Within the cytoplasm of these cells are secretory granules or vacuoles and pigment. Surrounding the epithelium is a thin lamina propria encircled by a very thin layer of smooth muscle. Outside the smooth muscle lies loose to compact connective tissue that forms the interstitium or stroma of the epididymis.<br />
<br />
=== Slide 229, Ductus Epididymis (Masson) ===<br />
<br />
Observe:<br />
<br />
That numerous coils of the duct have been sectioned in various planes.<br />
<br />
The relatively smooth lumen of the duct, owing to the uniform thickness of the epithelium and the stereocilia extending into the lumen.<br />
<br />
The sperm stored within the lumen.<br />
<br />
The scant amount of stromal connective tissue and smooth muscle surrounding the various coils of the duct.<br />
<br />
<peir-vm>UAB-Histology-00229</peir-vm><br />
<br />
=== Slide 6, Ductus Epididymis (H&E) ===<br />
<br />
Note especially the pseudostratified columnar epithelium possessing tall stereocilia.<br />
<br />
<peir-vm>UAB-Histology-00006</peir-vm><br />
<br />
=== Slide 230, Testis (H&E) ===<br />
<br />
Study slide 230, Testis (H&E) for comparison of efferent ducts and ductus epididymis.<br />
<br />
Locate the numerous sections of the ductus epididymis (lower right field in both slides). Again, note the relatively smooth outline of the luminal surface of the ductus epididymis. Compare the appearance of this duct with the scalloped appearance of the efferent ducts previously studied on these slides (in the upper fields) especially on slide 230 where the latter are more numerous.<br />
<br />
Ductus deferens. During development the testis descends from its early position on the posterior abdominal wall into the pelvis, and later during the seventh month of fetal life, it passes through the inguinal canal into the scrotum. Upon descending, each testis “pulls along” its vessels, nerves and ducts (ductus deferens) with it. These structures constitute the spermatic cord. The components of the spermatic cord are surrounded by connective tissue layers (fascia of gross anatomy) and by a somewhat discontinuous, longitudinally oriented layer of striated muscle fibers of the cremaster muscle.<br />
<br />
The constituents of the spermatic cord are the:<br />
<br />
*ductus deferens<br />
*artery of the ductus deferens<br />
*testicular artery<br />
*cremasteric artery<br />
*pampiniform plexus of veins<br />
*lymphatic vessels<br />
*nerves of the testis and epididymis<br />
<br />
<peir-vm>UAB-Histology-00230</peir-vm><br />
<br />
=== Slide 232, Spermatic Cord (H&E) ===<br />
<br />
Scan the tissue to observe:<br />
<br />
*The large ductus deferens with its thick muscular coat.<br />
<br />
*The numerous veins which constitute the pampiniform plexus. Some of these veins have unusually thick muscular tunics and bundles of longitudinally oriented muscle in the adventitia (medium-sized veins). <br />
<br />
*Arteries<br />
<br />
*Nerves<br />
<br />
*Connective tissue fibers and adipose tissue of the fascial layers.<br />
<br />
<peir-vm>UAB-Histology-00232</peir-vm><br />
<br />
== Accessory Glands ==<br />
<br />
=== Prostate Gland ===<br />
<br />
The prostate gland is an accessory, unpaired sex gland of males that surrounds the urethra as it leaves the bladder. The prostate is an aggregation of 30 to 50 branched tubuloalveolar glands that secrete a milky fluid rich in citric acid and acid phosphatase. Grossly, the prostate gland has five lobes and is about one and a half inches in diameter. It is surrounded by a fibromuscular capsule.<br />
<br />
The individual glands making up the overall prostate are arranged into a mucosal, a submucosal, and a main group of glands. They lie embedded in a fibromuscular stroma. The prostatic urethra traverses the prostate gland from superior to inferior surfaces. On each side of the prostatic utricle (the male homologue to the vagina) are located the ejaculatory ducts which open into the prostatic urethra. The ejaculatory ducts and the prostatic utricle are located in the seminal colliculus, an elevated portion of the urethral crest. The urethral crest is a longitudinal ridge that forms the posterior wall of the prostatic urethra.<br />
<br />
==== Slide 123, Prostate (H&E) ====<br />
<br />
Study Slide 123, Prostate (H&E) which is a section of the prostate from a 26- year-old male. Under low power note the numerous glands surrounded by the fibromuscular stroma. These glands are from the main group of glands of the prostate. Study them for detail noting that:<br />
<br />
The epithelium is low pseudostratified, having columnar cells and basal cells resting on a thin basement membrane (not seen here). The apices of the columnar cells appear “washed out” (poorly stained) indicating that some of the secretory material has been lost in fixation and/or that the secretory droplets stain poorly with H&E. The apices of most of the secretory cells stain positively with lipid stains.<br />
<br />
The epithelium shows numerous folds. Some of the folds have been sectioned tangentially and here the epithelium appears stratified. In other areas, the folds are cut through and appear as small “isolated islands” of epithelium.<br />
<br />
Eosinophilic prostatic concretions (corpora amylacea) can be seen within the lumina of the glands. These rounded bodies increase with age following adulthood. They contain carbohydrate and protein and may become large enough to occlude the lumens of the glands. When calcified they are called calculi.<br />
<br />
Study the abundant fibromuscular stroma making up about one-fourth to one-third of the gland. Strands of smooth muscle varying in thickness are intermixed with collagenous and elastic fibers. The muscle does not appear to have definite orientation or layers. This fibromuscular stroma is a distinctive feature of the prostate.<br />
<br />
<peir-vm>UAB-Histology-00123</peir-vm><br />
<br />
==== Slide 124, Prostatic Urethra (H&E) ====<br />
<br />
On slide 124, Prostatic Urethra (H&E), the general distribution of the somewhat concentrically arranged mucosal, submucosal and main prostatic glands can be studied. Identify these glands according to their locations.<br />
<br />
The mucosal glands are smallest and are periurethral in position (next to the urethra). Their ducts open at various points into the urethra. (These are small, few in number and may be absent on your section.)<br />
<br />
The submucosal glands are immediately peripheral to the mucosal ones, and the main glands which are largest and most numerous, lie to the outside of the submucosal glands on the periphery of the section. The ducts of the submucosal and main glands open into the urethral sinuses.<br />
<br />
Abnormalities are present. Some of the main glands show cystic dilations.<br />
<br />
The epithelium of these cystic glands is less folded than in the normal glands and in some regions appears to be squamous and less secretory than normal. Some glands may show lymphocytic infiltration. Others have stratified epithelium (hyperplasia).<br />
<br />
Study the prostatic urethra, a U-shaped groove in the prostate, and the urethral crest, a longitudinal ridge that forms the posterior wall of the prostatic urethra. The posterolateral portions of the urethra on each side of the urethral crest are the urethral sinuses. It is here where the ducts of the submucosal and main glands empty secretions into the urethra.<br />
<br />
Note the epithelium of the urethra. It is usually classified as transitional epithelium but patches of stratified columnar epithelium may be present.<br />
<br />
Most slides do not have ejaculatory ducts or the prostatic utricle since the section was taken through the prostate superior to the entrance of these structures into the urethra, but parts of these two structures may be present. The part of the urethral crest in which the prostatic utricle is located is the colliculus seminalis.<br />
<br />
Observe the periurethral vascular supply and the venous plexuses in the urethral crest.<br />
<br />
<peir-vm>UAB-Histology-00124</peir-vm><br />
<br />
=== Seminal Vesicles ===<br />
<br />
The seminal vesicles are paired saccular organs each in the form of a convoluted tube. They lie posterior to the prostate and their secretions, rich in fructose, enter the ejaculatory ducts just below the ampulla of the ductus deferens. The three layers of the gland are a mucosa, a muscularis and an adventitia (= fibrosa). The single lumen is irregular and branching with numerous lateral outpocketings.<br />
<br />
==== Slide 237, Seminal Vesicle (H&E) ====<br />
<br />
Observe that the gland appears to possess numerous lumina. Actually only one continuous cavity is present, but when the numerous convolutions of the gland are cut in one plane, separate cavities appear to be present.<br />
<br />
Note the complicated folding of the mucosa in which thin primary folds often exhibit secondary and tertiary branching.<br />
<br />
The muscularis contains an inner circular and an outer longitudinal layer of smooth muscle; two layers are not easily distinguishable in a section. <br />
<br />
The adventitia or fibrosa is rich in elastic fibers. It contains large blood vessels, nerves, and blends with other connective tissue surrounding the gland. One or more ganglia may be present.<br />
<br />
With high power study the mucosa on slide 237. The epithelium may appear to be simple cuboidal or low columnar, but the presence of basal cells makes it a low pseudostratified epithelium. The lining cells are secretory. A few granules may be present, or vacuoles may occur where they were dissolved away. Look for yellow or brownish lipochrome pigment in the surface cells. This pigment gives a yellowish tinge to the viscid secretions coming from these glands. The pigment begins to appear at puberty and increases with age. Beneath the epithelium is a basement membrane and a thin lamina propria with abundant elastic fibers. <br />
<br />
<peir-vm>UAB-Histology-00237</peir-vm><br />
<br />
=== Bulbourethral Gland ===<br />
<br />
==== Slide 238, Bulbourethral Gland (Masson) ====<br />
<br />
Scan Slide 238, Bulbourethral gland (Masson) to observe that:<br />
<br />
The irregular lobules of this compound tubuloalveolar gland are separated from each other by connective tissue septa that extend inward from a thin capsule.<br />
<br />
At the periphery of the gland and also in the connective tissue septa between some of the lobules can be seen skeletal muscle fibers.<br />
<br />
Interlobular excretory ducts lie within some of the larger connective tissue septa. (See e below)<br />
<br />
With high power study the parenchyma consisting of pale secretory cells, usually cuboidal to columnar in shape. They resemble mucous cells. The nucleus tends to be flattened at the base of the cells; however, some are rounded, others are oval and vertically oriented. The varying shapes of the nuclei probably indicate different states of secretory activity exhibited by the cells at the time of fixation. A mucus-like discharge from these glands lubricates the urethra during sexual simulation.<br />
<br />
In the smaller ducts of the bulbourethral gland the epithelium is simple and quite variable ranging from low cuboidal to columnar. The large excretory ducts are lined by stratified columnar epithelium that may contain patches of secreting cells. Smooth muscle fibers can usually be found among the connective tissue fibers surrounding these ducts and also in other regions of the connective tissue septa.<br />
<br />
<peir-vm>UAB-Histology-00238</peir-vm><br />
<br />
== Penis ==<br />
<br />
=== Slide 284, Penis (H&E) ===<br />
<br />
The penis is composed of erectile tissue and contains the section of penile urethra. The erectile tissue is composed of two dorsal cylinders (corpora cavernosa) and a smaller central ventral cylinder (corpus spongiosum) through which the penile urethra runs. These cylinders are each surrounded by a dense fibrocollagenous sheath, the tunica albuginea. The erectile tissues are essentially interconnecting vascular spaces which are empty when the penis is flaccid but which become engorged with blood during an erection. <br />
<br />
The blood supply to the penis is provided by the dorsal and the deep arteries. From the deep arteries arise arteries supplying the tunica albuginea, and the helicine arteries, which supply the erectile tissue. The helicine arteries form convoluted vessels in the flaccid penis but during erection they straighten and dilate, filling the corpora with blood. This filling effect is partly due to closure of the arteriovenous shunts existing between the helicine arteries and deep veins, which constitute the normal route of helicine artery blood flow in the flaccid state. Parasympathetic nerve discharges cause the closure, leading to diversion of the helicine artery blood into the cavernous spaces, while increased pressure in the corpora compresses the thin-walled veins, preventing emptying. After ejaculation the parasympathetic stimulation ceases, the arteriovenous shunts open and blood passes from the corpora into the veins.<br />
<br />
At the distal end of the penis the corpus spongiosum terminates on the glans penis, which is covered with non-keratinizing squamous epithelium containing sebaceous glands. The penile urethra opens to the exterior at the meatus at the centre of the glans penis<br />
<br />
For most of its length the penile urethra is lined by non-secreting columnar epithelium into which small mucus glands embedded in the corpus spongiosum drain. Within the glans penis, however, the urethra dilates (navicular fossa) and becomes lined by non-keratinizing stratified squamous epithelium identical to that covering the glans.<br />
<br />
<peir-vm>UAB-Histology-00284</peir-vm><br />
<br />
{{Template:Histologic}}<br />
<br />
[[Category:Histologic]]</div>Matthew Andersonhttps://peir.path.uab.edu/index.php?title=File:HistologicChapter16Testis.jpg&diff=3248File:HistologicChapter16Testis.jpg2014-07-18T19:07:26Z<p>Matthew Anderson: </p>
<hr />
<div></div>Matthew Andersonhttps://peir.path.uab.edu/index.php?title=Template:Histologic&diff=3247Template:Histologic2014-07-18T19:04:40Z<p>Matthew Anderson: </p>
<hr />
<div>{{Navbox<br />
|name = Histologic<br />
|title = [[Histologic]]<br />
|bodyclass = hlist<br />
[[Histologic]]<br />
|group1 = [[Histologic:Chapter 1|Chapter 1]]<br />
|list1 =<br />
* [[Histologic:Chapter 1#Introduction|Introduction]]<br />
* [[Histologic:Chapter 1#Overview_of_Tissue_Preparation_and_Staining_for_Microscopy|Overview of Tissue Preparation and Staining for Microscopy]]<br />
* [[Histologic:Chapter 1#Using_Histologic|Using Histologic]]<br />
|group2 = [[Histologic:Chapter 2|Chapter 2]]<br />
|list2 =<br />
* [[Histologic:Chapter 2#Cells,_Organelles,_and_Inclusions|Cells, Organelles, and Inclusions]]<br />
* [[Histologic:Chapter 2#Mitosis|Mitosis]]<br />
|group3 = [[Histologic:Chapter 3|Chapter 3]]<br />
|list3 =<br />
* [[Histologic:Chapter 3#Introduction|Introduction]]<br />
* [[Histologic:Chapter 3#Simple_Epithelium|Simple Epithelium]]<br />
* [[Histologic:Chapter 3#Stratified_Epithelium|Stratified Epithelium]]<br />
|group4 = [[Histologic:Chapter 4|Chapter 4]]<br />
|list4 =<br />
* [[Histologic:Chapter 4#Introduction|Introduction]]<br />
* [[Histologic:Chapter 4#Loose_Connective_Tissue|Loose Connective Tissue]]<br />
* [[Histologic:Chapter 4#Dense_Connective_Tissue|Dense Connective Tissue]]<br />
* [[Histologic:Chapter 4#Adipose_Tissue|Adipose Tissue]]<br />
|group5 = [[Histologic:Chapter 5|Chapter 5]]<br />
|list5 =<br />
* [[Histologic:Chapter 5#Introduction|Introduction]]<br />
* [[Histologic:Chapter 5#Smooth_Muscle|Smooth Muscle]]<br />
* [[Histologic:Chapter 5#Skeletal_Muscle|Skeletal Muscle]]<br />
* [[Histologic:Chapter 5#Cardiac_Muscle|Cardiac Muscle]]<br />
|group6 = [[Histologic:Chapter 6|Chapter 6]]<br />
|list6 =<br />
* [[Histologic:Chapter 6#Introduction|Introduction]]<br />
* [[Histologic:Chapter 6#Nerve_Fibers_And_Nerves|Nerve Fibers And Nerves]]<br />
* [[Histologic:Chapter 6#Central_Nervous_System:_Brain|Central Nervous System: Brain]]<br />
* [[Histologic:Chapter 6#Spinal_Cord_-_General_Structure|Spinal Cord - General Structure]]<br />
* [[Histologic:Chapter 6#Sympathetic_Chain_Ganglion_With_Multipolar_Neurons|Sympathetic Chain Ganglion With Multipolar Neurons]]<br />
* [[Histologic:Chapter 6#Parasympathetic_Ganglia|Parasympathetic Ganglia]]<br />
|group7 = [[Histologic:Chapter 7|Chapter 7]]<br />
|list7 =<br />
* [[Histologic:Chapter 7#Introduction|Introduction]]<br />
* [[Histologic:Chapter 7#Blood_Smears|Blood Smears]]<br />
|group8 = [[Histologic:Chapter 8|Chapter 8]]<br />
|list8 =<br />
* [[Histologic:Chapter 8#Introduction|Introduction]]<br />
* [[Histologic:Chapter 8#Lymph_Nodes|Lymph Nodes]]<br />
* [[Histologic:Chapter 8#Thymus|Thymus]]<br />
* [[Histologic:Chapter 8#Tonsils|Tonsils]]<br />
* [[Histologic:Chapter 8#Spleen|Spleen]]<br />
|group9 = [[Histologic:Chapter 9|Chapter 9]]<br />
|list9 =<br />
* [[Histologic:Chapter 9#Introduction|Introduction]]<br />
* [[Histologic:Chapter 9#Small_Blood_Vessels|Small Blood Vessels]]<br />
* [[Histologic:Chapter 9#Medium-Sized_Blood_Vessels|Medium-Sized Blood Vessels]]<br />
* [[Histologic:Chapter 9#Large_Arteries|Large Arteries]]<br />
* [[Histologic:Chapter 9#Large_Veins|Large Veins]]<br />
|group10 = [[Histologic:Chapter 10|Chapter 10]]<br />
|list10 =<br />
* [[Histologic:Chapter 10#Olfactory_Area|Olfactory Area]]<br />
* [[Histologic:Chapter 10#Epiglottis|Epiglottis]]<br />
* [[Histologic:Chapter 10#Trachea|Trachea]]<br />
* [[Histologic:Chapter 10#Bronchi,_Bronchioles,_and_Lung|Bronchi, Bronchioles, and Lung]]<br />
|group11 = [[Histologic:Chapter 11|Chapter 11]]<br />
|list11 =<br />
* [[Histologic:Chapter 11#Lip|Lip]]<br />
* [[Histologic:Chapter 11#Tongue|Tongue]]<br />
* [[Histologic:Chapter 11#Salivary_Glands|Salivary Glands]]<br />
* [[Histologic:Chapter 11#Pancreas|Pancreas]]<br />
* [[Histologic:Chapter 11#Esophagus|Esophagus]]<br />
* [[Histologic:Chapter 11#Stomach|Stomach]]<br />
* [[Histologic:Chapter 11#Small_Intestine|Small Intestine]]<br />
* [[Histologic:Chapter 11#Pylorus-Duodenal_Junction|Pylorus-Duodenal Junction]]<br />
* [[Histologic:Chapter 11#Duodenum|Duodenum]]<br />
* [[Histologic:Chapter 11#Jejunum|Jejunum]]<br />
* [[Histologic:Chapter 11#Ileum|Ileum]]<br />
* [[Histologic:Chapter 11#Appendix|Appendix]]<br />
* [[Histologic:Chapter 11#Colon|Colon]]<br />
* [[Histologic:Chapter 11#Rectum|Rectum]]<br />
* [[Histologic:Chapter 11#Anal_Canal|Anal Canal]]<br />
|group12 = [[Histologic:Chapter 12|Chapter 12]]<br />
|list12 =<br />
* [[Histologic:Chapter 12#Introduction|Introduction]]<br />
* [[Histologic:Chapter 12#Gallbladder|Gallbladder]]<br />
|group13 = [[Histologic:Chapter 13|Chapter 13]]<br />
|list13 =<br />
* [[Histologic:Chapter 13#Skeletal_Muscle|Skeletal Muscle]]<br />
* [[Histologic:Chapter 13#Cartilage|Cartilage]]<br />
* [[Histologic:Chapter 13#Bone|Bone]]<br />
* [[Histologic:Chapter 13#Joints|Joints]]<br />
|group14 = [[Histologic:Chapter 14|Chapter 14]]<br />
|list14 =<br />
* [[Histologic:Chapter 14#Introduction|Introduction]]<br />
* [[Histologic:Chapter 14#Pituitary_Gland_(Hypophysis)|Pituitary Gland (Hypophysis)]]<br />
* [[Histologic:Chapter 14#Thyroid|Thyroid]]<br />
* [[Histologic:Chapter 14#Parathyroid|Parathyroid]]<br />
* [[Histologic:Chapter 14#Suprarenal_(Adrenal)_Glands|Suprarenal (Adrenal) Glands]]<br />
* [[Histologic:Chapter 14#Endocrine_Pancreas_(Pancreatic_Islets_of_Langerhans)|Endocrine Pancreas (Pancreatic Islets of Langerhans)]]<br />
|group15 = [[Histologic:Chapter 15|Chapter 15]]<br />
|list15 =<br />
* [[Histologic:Chapter 15#Kidney|Kidney]]<br />
* [[Histologic:Chapter 15#Ureter_and_Urinary_Bladder|Ureter And Urinary Bladder]]<br />
|group16 = [[Histologic:Chapter 16|Chapter 16]]<br />
|list16 =<br />
* [[Histologic:Chapter 16#Introduction|Introduction]]<br />
* [[Histologic:Chapter 16#The_Testis|The Testis]]<br />
* [[Histologic:Chapter 16#Genital_Ducts|Genital Ducts]]<br />
* [[Histologic:Chapter 16#Accessory_Glands|Accessory Glands]]<br />
* [[Histologic:Chapter 16#Penis|Penis]]<br />
|group17 = [[Histologic:Chapter 17|Chapter 17]]<br />
|list17 =<br />
* [[Histologic:Chapter 17#Introduction|Introduction]]<br />
|group18 = [[Histologic:Chapter 18|Chapter 18]]<br />
|list18 =<br />
* [[Histologic:Chapter 18#Introduction|Introduction]]<br />
|group19 = [[Histologic:Chapter 19|Chapter 19]]<br />
|list19 =<br />
* [[Histologic:Chapter 19#Introduction|Introduction]]<br />
|group20 = [[Histologic:Contributors|Contributors]]<br />
|list20 =<br />
* [[Histologic:Contributors#Acknowledgements|Acknowledgements]]<br />
* [[Histologic:Contributors#Staff|Staff]]<br />
<br />
}}<noinclude><br />
<br />
[[Category:Histologic Templates]]<br />
[[Category:Histologic]]<br />
</noinclude></div>Matthew Andersonhttps://peir.path.uab.edu/index.php?title=Histologic&diff=3246Histologic2014-07-18T19:03:52Z<p>Matthew Anderson: </p>
<hr />
<div>Welcome to [[Histologic]], a constantly-updated, wiki-based comprehensive manual for the teaching of histology at the [http://www.uab.edu/medicine/home/ University of Alabama at Birmingham School of Medicine]. It integrates still images from the [{{SERVER}}/library PEIR Digital Library] and whole slide images from the [http://peir-vm.path.uab.edu PEIR-VM] project. For usage instructions, please see [[Histologic:Chapter 1|Chapter 1]]. To get in touch with us, please see [[Histologic:Contributors|Contributors]].<br />
<br />
== [[Histologic:Chapter 1|Chapter 1: Overview]] ==<br />
* [[Histologic:Chapter 1#Introduction|Introduction]]<br />
* [[Histologic:Chapter 1#Overview_of_Tissue_Preparation_and_Staining_for_Microscopy|Overview of Tissue Preparation and Staining for Microscopy]]<br />
* [[Histologic:Chapter 1#Using_Histologic|Using Histologic]]<br />
<br />
== [[Histologic:Chapter 2|Chapter 2: The Cell]] ==<br />
* [[Histologic:Chapter 2#Cells,_Organelles,_and_Inclusions|Cells, Organelles, and Inclusions]]<br />
* [[Histologic:Chapter 2#Mitosis|Mitosis]]<br />
<br />
== [[Histologic:Chapter 3|Chapter 3: Epithelial Cells]] ==<br />
* [[Histologic:Chapter 3#Introduction|Introduction]]<br />
* [[Histologic:Chapter 3#Simple_Epithelium|Simple Epithelium]]<br />
* [[Histologic:Chapter 3#Stratified_Epithelium|Stratified Epithelium]]<br />
<br />
== [[Histologic:Chapter 4|Chapter 4: Support Cells and the Extracellular Matrix]] ==<br />
* [[Histologic:Chapter 4#Introduction|Introduction]]<br />
* [[Histologic:Chapter 4#Loose_Connective_Tissue|Loose Connective Tissue]]<br />
* [[Histologic:Chapter 4#Dense_Connective_Tissue|Dense Connective Tissue]]<br />
* [[Histologic:Chapter 4#Adipose_Tissue|Adipose Tissue]]<br />
<br />
== [[Histologic:Chapter 5|Chapter 5: Contractile Cells]] ==<br />
* [[Histologic:Chapter 5#Introduction|Introduction]]<br />
* [[Histologic:Chapter 5#Smooth_Muscle|Smooth Muscle]]<br />
* [[Histologic:Chapter 5#Skeletal_Muscle|Skeletal Muscle]]<br />
* [[Histologic:Chapter 5#Cardiac_Muscle|Cardiac Muscle]]<br />
<br />
== [[Histologic:Chapter 6|Chapter 6: Nervous Tissue]] ==<br />
* [[Histologic:Chapter 6#Introduction|Introduction]]<br />
* [[Histologic:Chapter 6#Nerve_Fibers_And_Nerves|Nerve Fibers And Nerves]]<br />
* [[Histologic:Chapter 6#Central_Nervous_System:_Brain|Central Nervous System: Brain]]<br />
* [[Histologic:Chapter 6#Spinal_Cord_-_General_Structure|Spinal Cord - General Structure]]<br />
* [[Histologic:Chapter 6#Sympathetic_Chain_Ganglion_With_Multipolar_Neurons|Sympathetic Chain Ganglion With Multipolar Neurons]]<br />
* [[Histologic:Chapter 6#Parasympathetic_Ganglia|Parasympathetic Ganglia]]<br />
<br />
== [[Histologic:Chapter 7|Chapter 7: Blood Cells]] ==<br />
* [[Histologic:Chapter 7#Introduction|Introduction]]<br />
* [[Histologic:Chapter 7#Blood_Smears|Blood Smears]]<br />
<br />
== [[Histologic:Chapter 8|Chapter 8: Immune System]] ==<br />
* [[Histologic:Chapter 8#Introduction|Introduction]]<br />
* [[Histologic:Chapter 8#Lymph_Nodes|Lymph Nodes]]<br />
* [[Histologic:Chapter 8#Thymus|Thymus]]<br />
* [[Histologic:Chapter 8#Tonsils|Tonsils]]<br />
* [[Histologic:Chapter 8#Spleen|Spleen]]<br />
<br />
== [[Histologic:Chapter 9|Chapter 9: Blood and Lymphatic Circulatory Systems and Heart]] ==<br />
* [[Histologic:Chapter 9#Introduction|Introduction]]<br />
* [[Histologic:Chapter 9#Small_Blood_Vessels|Small Blood Vessels]]<br />
* [[Histologic:Chapter 9#Medium-Sized_Blood_Vessels|Medium-Sized Blood Vessels]]<br />
* [[Histologic:Chapter 9#Large_Arteries|Large Arteries]]<br />
* [[Histologic:Chapter 9#Large_Veins|Large Veins]]<br />
<br />
== [[Histologic:Chapter 10|Chapter 10: Respiratory System]] ==<br />
* [[Histologic:Chapter 10#Olfactory_Area|Olfactory Area]]<br />
* [[Histologic:Chapter 10#Epiglottis|Epiglottis]]<br />
* [[Histologic:Chapter 10#Trachea|Trachea]]<br />
* [[Histologic:Chapter 10#Bronchi,_Bronchioles,_and_Lung|Bronchi, Bronchioles, and Lung]]<br />
<br />
== [[Histologic:Chapter 11|Chapter 11: Alimentary Tract]] ==<br />
* [[Histologic:Chapter 11#Lip|Lip]]<br />
* [[Histologic:Chapter 11#Tongue|Tongue]]<br />
* [[Histologic:Chapter 11#Salivary_Glands|Salivary Glands]]<br />
* [[Histologic:Chapter 11#Pancreas|Pancreas]]<br />
* [[Histologic:Chapter 11#Esophagus|Esophagus]]<br />
* [[Histologic:Chapter 11#Stomach|Stomach]]<br />
* [[Histologic:Chapter 11#Small_Intestine|Small Intestine]]<br />
* [[Histologic:Chapter 11#Pylorus-Duodenal_Junction|Pylorus-Duodenal Junction]]<br />
* [[Histologic:Chapter 11#Duodenum|Duodenum]]<br />
* [[Histologic:Chapter 11#Jejunum|Jejunum]]<br />
* [[Histologic:Chapter 11#Ileum|Ileum]]<br />
* [[Histologic:Chapter 11#Appendix|Appendix]]<br />
* [[Histologic:Chapter 11#Colon|Colon]]<br />
* [[Histologic:Chapter 11#Rectum|Rectum]]<br />
* [[Histologic:Chapter 11#Anal_Canal|Anal Canal]]<br />
<br />
== [[Histologic:Chapter 12|Chapter 12: Liver]] ==<br />
* [[Histologic:Chapter 12#Introduction|Introduction]]<br />
* [[Histologic:Chapter 12#Gallbladder|Gallbladder]]<br />
<br />
== [[Histologic:Chapter 13|Chapter 13: Musculoskeletal System]] ==<br />
* [[Histologic:Chapter 13#Skeletal_Muscle|Skeletal Muscle]]<br />
* [[Histologic:Chapter 13#Cartilage|Cartilage]]<br />
* [[Histologic:Chapter 13#Bone|Bone]]<br />
* [[Histologic:Chapter 13#Joints|Joints]]<br />
<br />
== [[Histologic:Chapter 14|Chapter 14: Endocrine System]] ==<br />
* [[Histologic:Chapter 14#Introduction|Introduction]]<br />
* [[Histologic:Chapter 14#Pituitary_Gland_(Hypophysis)|Pituitary Gland (Hypophysis)]]<br />
* [[Histologic:Chapter 14#Thyroid|Thyroid]]<br />
* [[Histologic:Chapter 14#Parathyroid|Parathyroid]]<br />
* [[Histologic:Chapter 14#Suprarenal_(Adrenal)_Glands|Suprarenal (Adrenal) Glands]]<br />
* [[Histologic:Chapter 14#Endocrine_Pancreas_(Pancreatic_Islets_of_Langerhans)|Endocrine Pancreas (Pancreatic Islets of Langerhans)]]<br />
<br />
== [[Histologic:Chapter 15|Chapter 15: Urinary System]] ==<br />
* [[Histologic:Chapter 15#Kidney|Kidney]]<br />
* [[Histologic:Chapter 15#Ureter_and_Urinary_Bladder|Ureter And Urinary Bladder]]<br />
<br />
== [[Histologic:Chapter 16|Chapter 16: Male Reproductive System]] ==<br />
* [[Histologic:Chapter 16#Introduction|Introduction]]<br />
* [[Histologic:Chapter 16#The_Testis|The Testis]]<br />
* [[Histologic:Chapter 16#Genital_Ducts|Genital Ducts]]<br />
* [[Histologic:Chapter 16#Accessory_Glands|Accessory Glands]]<br />
* [[Histologic:Chapter 16#Penis|Penis]]<br />
<br />
== [[Histologic:Chapter 17|Chapter 17: Female Reproductive System]] ==<br />
* [[Histologic:Chapter 17#Introduction|Introduction]]<br />
<br />
== [[Histologic:Chapter 18|Chapter 18: Skin and Breast]] ==<br />
* [[Histologic:Chapter 18#Introduction|Introduction]]<br />
<br />
== [[Histologic:Chapter 19|Chapter 19: Special Senses]] ==<br />
* [[Histologic:Chapter 19#Introduction|Introduction]]<br />
<br />
== [[Histologic:Contributors|Contributors]] ==<br />
* [[Histologic:Contributors#Acknowledgements|Acknowledgements]]<br />
* [[Histologic:Contributors#Staff|Staff]]<br />
<br />
[[Category:Histologic]]</div>Matthew Andersonhttps://peir.path.uab.edu/index.php?title=Histologic:Chapter_16&diff=3245Histologic:Chapter 162014-07-18T19:01:32Z<p>Matthew Anderson: Created page with "== Introduction == The components of the male reproductive system include the testes, the genital ducts, the accessory glands, and the penis. == The Testis == The testis fu..."</p>
<hr />
<div>== Introduction ==<br />
<br />
The components of the male reproductive system include the testes, the genital ducts, the accessory glands, and the penis.<br />
<br />
== The Testis ==<br />
<br />
The testis functions as a cytogenic gland in that it produces spermatozoa and as an endocrine gland which produces the hormone testosterone. This hormone is essential for the proper development and maintenance of the accessory sexual organs, particularly the genital ducts and the accessory glands.<br />
<br />
The two ovoid testes lie in the scrotum. Each testis is covered by three tunics.<br />
<br />
*A prominent, tough, fibrous layer of connective tissue called the tunica albuginea forms the middle tunic.<br />
<br />
*Investing the tunica albuginea is a layer of squamous cells and a thin layer of loose connective tissue, the tunica vaginalis, which represents a serous lining of peritoneum “trapped” by the descended testis. This tunic is lacking on the posterior wall of the testis.<br />
<br />
*Internal to the tunica albuginea is a thin layer of loose, highly vascular connective tissue called the tunica vasculosa.<br />
<br />
The testis is divided into about 250 anastomosing, pyramidal-shaped lobules by delicate connective tissue septa, the septulae testis. The septa radiate from the mediastinum into the testis. Within the testicular lobules occur from one to four convoluted seminiferous tubules where spermatozoa are produced. <br />
<br />
The stroma of the testis lies between the seminiferous tubules. In addition to the usual connective tissue cells and collagenous fibers found in loose, vascular connective tissue, the stroma also contains endocrine tissue consisting of the interstitial cells (cells of Leydig). These cells produce the androgenic steroid hormone testosterone. Production of testosterone is stimulated by luteinizing hormone (LH = interstitial cell stimulating hormone, ICSH) produced by basophils of the anterior pituitary gland. Interstitial cells are polyhedral shaped cells (14 to 21 μm in diameter) with a large, rounded, sometimes wrinkled nucleus, and an acidophilic cytoplasm. The cytoplasm, in addition to the usual organelles, also contains a vast amount of smooth endoplasmic reticulum and mitochondria containing tubular cristae. These organelles are characteristic of cells which produce steroid hormones. Another cytoplasmic characteristic of interstitial cells are protein crystals (of Reinke) that vary in size, form and frequency of occurrence. The significance of these crystals is not clear.<br />
<br />
A seminiferous tubule has a highly complex stratified epithelium consisting of spermatogenic cells and supporting cells (= sustentacular or Sertoli cells). External to the basement membrane on which the epithelium rests is a tunic of fibroelastic tissue. The supporting cells are tall, irregular columnar cells extending from the basement membrane to the lumen of the seminiferous tubule. On the lateral and apical surfaces, numerous recesses are formed by the plasma membrane which “indents” the cytoplasm. Within these recesses or depressions lie developing spermatogenic cells. The elaborate shapes of the supporting cells are difficult to see unless the testis has been prepared by a silver technique which demonstrates the cell boundaries. The large nuclei (9 to 12 μm diameter) of supporting cells have a variable position ranging from the basal zone to the mid- region of the cell. The nucleus is usually ovoid, stains palely, and shows an unusual tripartite nucleolus possessing a central acidophilic mass flanked by two basophilic masses. The nuclear membrane is frequently folded or longitudinally indented. The presence of moderate amounts of smooth endoplasmic reticulum and other features characteristic of steroid producing cells have led to suggestions that the supporting cells may produce steroid hormones. The major role of these cells is in mechanical support, protection, and perhaps nourishment of the developing germ cells.<br />
<br />
=== Slide 227, Testis (H&E) === <br />
<br />
Scan this slide to observe:<br />
<br />
Section of testis containing sections of seminiferous tubules. Note the dense tunica albuginea, the tunica vasculosa, the septula testis and the connective tissue stroma or interstitial tissue.<br />
<br />
Identify the mediastinum testis containing the irregular channels of the rete testis. <br />
<br />
A portion of the epididymis is present (the mass of tissue at one end) and can be seen containing efferent ducts and sections of the ductus epididymis. The former are in the uppermost area, the latter in the lowermost region.<br />
<br />
Note the numerous blood vessels, nerves and abundance of connective tissue fibers and adipose tissue adjacent to the mediastinum and epididymis.<br />
<br />
Study the normal seminiferous tubules. Locate the three layers that constitute the wall of a tubule. These are:<br />
<br />
*An outermost layer of fibroelastic connective tissue.<br />
*A basement membrane on which the spermatogonial and supporting cells rest.<br />
*The complex stratified epithelium where spermatogenesis occurs.<br />
<br />
The three layers may be seen more easily on slide 228, Testis (Masson) where the basement membrane is stained blue.<br />
<br />
On slide 227, 228 and 230 identify the interstitial cells in the stromal tissue lying in angles between the seminiferous tubules. Interstitial cells are polyhedral in shape, have an acidophilic cytoplasm, and possess a rounded nucleus that usually contains one or two prominent nucleoli. The cytoplasm may be vacuolated where lipid droplets were dissolved away and an occasional cell may contain golden brown deposits of lipochrome pigment.<br />
<br />
On the same slides, identify the supporting cells (Sertoli cells) within the stratified epithelium of the seminiferous tubules. Their cell boundaries will not be seen, but one usually can identify the nuclei of these tall columnar cells. The ovoid nucleus stains palely, contains a nucleolus and will occupy a variable position ranging from near the basement membrane to the middle of the cell.<br />
<br />
Within the seminiferous tubules of slide 230 identify as many of the spermatogenic cells as possible. <br />
<br />
<peir-vm>UAB-Histology-00227</peir-vm><br />
<br />
==== Slide 228, Testis (Masson) ====<br />
<peir-vm>UAB-Histology-00228</peir-vm><br />
==== Slide 230, Testis ====<br />
<peir-vm>UAB-Histology-00230</peir-vm><br />
<br />
== Genital Ducts ==<br />
<br />
Straight tubules. On slide 227, Testis (H&E) identify the straight tubules located in a narrow region between the ends of the seminiferous tubules and the rete testis. The simple columnar epithelial cells, which line the initial segment of the straight tubules, resemble supporting cells. Near the rete testis the cells shorten to become cuboidal. These tubules have a uniformly narrow diameter.<br />
<br />
Rete testis. The rete testis is located in the connective tissue of the mediastinum testis. It is that portion of the genital ducts which unites the straight tubules (tubuli recti) with the efferent ducts. The rete testis is essentially a system of anastomosing channels of epithelial lined spaces within connective tissue. As such the epithelium of these irregular spaces consists of low simple cuboidal to simple squamous cells resting on a basement membrane. A single cilium may occur on some of the cells. (Not seen on our slide.) A distinct lamina propria and muscularis are lacking. On slides 227 and 230 locate and study the rete testis in the dense connective tissue of the mediastinum. On these slides, its extent varies from extensive to virtually absent.<br />
<br />
Efferent ducts. Efferent ducts (ductuli efferentes). About twelve to fifteen ductules (0.6 mm in diameter, 4 to 6 mm long) called efferent ducts unite the rete testis with the ductus epididymis. The ductules emerge from the mediastinum to the surface of the testis where they form cone-shaped coils that constitute much of the head of the epididymis. The efferent ducts consist of an epithelium resting on a thin basement membrane and some circularly oriented smooth muscle fibers embedded within the connective tissue surrounding the ductules.<br />
<br />
On slide 227, Testis (H&E), and slide 230, Testis, (H&E) locate the efferent ducts in the epididymal region by the scalloped or undulated appearance of the epithelium. They appear in the lower right field on slide 227 and in the upper right field on slide 230. The epithelium is pseudostratified with small basal cells near the basement membrane and larger columnar or cuboidal surface cells. This gives the luminal surface of the ducts an irregular contour. The columnar cells are usually ciliated, whereas microvilli extend into the lumen from the cuboidal cells. (Cilia and microvilli are difficult to see on our slide.) Transport of sperm to the ductus epididymis is facilitated by the beating of the cilia. Motile cilia in the male genital ducts are found here and in the rete testis. The microvilli probably serve an absorptive function. Pigment granules and pale secretion granules may sometimes be seen in both types of surface cells of the ducts. Also, clear areas occur within the cells where fat has been dissolved away. On the upper right edge of slide 230 is a long, cystic tubule, probably an efferent duct that became obstructed.<br />
<br />
Ductus epididymis. The epididymis lies on the posterior side of the testis. The ductus epididymis consists of a highly coiled duct (or tube) five to six meters in length, surrounded by smooth muscle and connective tissue. It occupies the body and the tail of the epididymis. The ductus epididymis unites proximally with the efferent ducts and distally with the ductus deferens. The duct is lined with a pseudostratified columnar epithelium consisting of tall columnar cells and smaller rounded basal cells. Large, nonmotile, branching microvilli called stereocilia extend from the apices of the columnar cells. Within the cytoplasm of these cells are secretory granules or vacuoles and pigment. Surrounding the epithelium is a thin lamina propria encircled by a very thin layer of smooth muscle. Outside the smooth muscle lies loose to compact connective tissue that forms the interstitium or stroma of the epididymis.<br />
<br />
=== Slide 229, Ductus Epididymis (Masson) ===<br />
<br />
Observe:<br />
<br />
That numerous coils of the duct have been sectioned in various planes.<br />
<br />
The relatively smooth lumen of the duct, owing to the uniform thickness of the epithelium and the stereocilia extending into the lumen.<br />
<br />
The sperm stored within the lumen.<br />
<br />
The scant amount of stromal connective tissue and smooth muscle surrounding the various coils of the duct.<br />
<br />
<peir-vm>UAB-Histology-00229</peir-vm><br />
<br />
=== Slide 6, Ductus Epididymis (H&E) ===<br />
<br />
Note especially the pseudostratified columnar epithelium possessing tall stereocilia.<br />
<br />
<peir-vm>UAB-Histology-00006</peir-vm><br />
<br />
=== Slide 230, Testis (H&E) ===<br />
<br />
Study slide 230, Testis (H&E) for comparison of efferent ducts and ductus epididymis.<br />
<br />
Locate the numerous sections of the ductus epididymis (lower right field in both slides). Again, note the relatively smooth outline of the luminal surface of the ductus epididymis. Compare the appearance of this duct with the scalloped appearance of the efferent ducts previously studied on these slides (in the upper fields) especially on slide 230 where the latter are more numerous.<br />
<br />
Ductus deferens. During development the testis descends from its early position on the posterior abdominal wall into the pelvis, and later during the seventh month of fetal life, it passes through the inguinal canal into the scrotum. Upon descending, each testis “pulls along” its vessels, nerves and ducts (ductus deferens) with it. These structures constitute the spermatic cord. The components of the spermatic cord are surrounded by connective tissue layers (fascia of gross anatomy) and by a somewhat discontinuous, longitudinally oriented layer of striated muscle fibers of the cremaster muscle.<br />
<br />
The constituents of the spermatic cord are the:<br />
<br />
*ductus deferens<br />
*artery of the ductus deferens<br />
*testicular artery<br />
*cremasteric artery<br />
*pampiniform plexus of veins<br />
*lymphatic vessels<br />
*nerves of the testis and epididymis<br />
<br />
<peir-vm>UAB-Histology-00230</peir-vm><br />
<br />
=== Slide 232, Spermatic Cord (H&E) ===<br />
<br />
Scan the tissue to observe:<br />
<br />
*The large ductus deferens with its thick muscular coat.<br />
<br />
*The numerous veins which constitute the pampiniform plexus. Some of these veins have unusually thick muscular tunics and bundles of longitudinally oriented muscle in the adventitia (medium-sized veins). <br />
<br />
*Arteries<br />
<br />
*Nerves<br />
<br />
*Connective tissue fibers and adipose tissue of the fascial layers.<br />
<br />
<peir-vm>UAB-Histology-00232</peir-vm><br />
<br />
== Accessory Glands ==<br />
<br />
=== Prostate Gland ===<br />
<br />
The prostate gland is an accessory, unpaired sex gland of males that surrounds the urethra as it leaves the bladder. The prostate is an aggregation of 30 to 50 branched tubuloalveolar glands that secrete a milky fluid rich in citric acid and acid phosphatase. Grossly, the prostate gland has five lobes and is about one and a half inches in diameter. It is surrounded by a fibromuscular capsule.<br />
<br />
The individual glands making up the overall prostate are arranged into a mucosal, a submucosal, and a main group of glands. They lie embedded in a fibromuscular stroma. The prostatic urethra traverses the prostate gland from superior to inferior surfaces. On each side of the prostatic utricle (the male homologue to the vagina) are located the ejaculatory ducts which open into the prostatic urethra. The ejaculatory ducts and the prostatic utricle are located in the seminal colliculus, an elevated portion of the urethral crest. The urethral crest is a longitudinal ridge that forms the posterior wall of the prostatic urethra.<br />
<br />
==== Slide 123, Prostate (H&E) ====<br />
<br />
Study Slide 123, Prostate (H&E) which is a section of the prostate from a 26- year-old male. Under low power note the numerous glands surrounded by the fibromuscular stroma. These glands are from the main group of glands of the prostate. Study them for detail noting that:<br />
<br />
The epithelium is low pseudostratified, having columnar cells and basal cells resting on a thin basement membrane (not seen here). The apices of the columnar cells appear “washed out” (poorly stained) indicating that some of the secretory material has been lost in fixation and/or that the secretory droplets stain poorly with H&E. The apices of most of the secretory cells stain positively with lipid stains.<br />
<br />
The epithelium shows numerous folds. Some of the folds have been sectioned tangentially and here the epithelium appears stratified. In other areas, the folds are cut through and appear as small “isolated islands” of epithelium.<br />
<br />
Eosinophilic prostatic concretions (corpora amylacea) can be seen within the lumina of the glands. These rounded bodies increase with age following adulthood. They contain carbohydrate and protein and may become large enough to occlude the lumens of the glands. When calcified they are called calculi.<br />
<br />
Study the abundant fibromuscular stroma making up about one-fourth to one-third of the gland. Strands of smooth muscle varying in thickness are intermixed with collagenous and elastic fibers. The muscle does not appear to have definite orientation or layers. This fibromuscular stroma is a distinctive feature of the prostate.<br />
<br />
<peir-vm>UAB-Histology-00123</peir-vm><br />
<br />
==== Slide 124, Prostatic Urethra (H&E) ====<br />
<br />
On slide 124, Prostatic Urethra (H&E), the general distribution of the somewhat concentrically arranged mucosal, submucosal and main prostatic glands can be studied. Identify these glands according to their locations.<br />
<br />
The mucosal glands are smallest and are periurethral in position (next to the urethra). Their ducts open at various points into the urethra. (These are small, few in number and may be absent on your section.)<br />
<br />
The submucosal glands are immediately peripheral to the mucosal ones, and the main glands which are largest and most numerous, lie to the outside of the submucosal glands on the periphery of the section. The ducts of the submucosal and main glands open into the urethral sinuses.<br />
<br />
Abnormalities are present. Some of the main glands show cystic dilations.<br />
<br />
The epithelium of these cystic glands is less folded than in the normal glands and in some regions appears to be squamous and less secretory than normal. Some glands may show lymphocytic infiltration. Others have stratified epithelium (hyperplasia).<br />
<br />
Study the prostatic urethra, a U-shaped groove in the prostate, and the urethral crest, a longitudinal ridge that forms the posterior wall of the prostatic urethra. The posterolateral portions of the urethra on each side of the urethral crest are the urethral sinuses. It is here where the ducts of the submucosal and main glands empty secretions into the urethra.<br />
<br />
Note the epithelium of the urethra. It is usually classified as transitional epithelium but patches of stratified columnar epithelium may be present.<br />
<br />
Most slides do not have ejaculatory ducts or the prostatic utricle since the section was taken through the prostate superior to the entrance of these structures into the urethra, but parts of these two structures may be present. The part of the urethral crest in which the prostatic utricle is located is the colliculus seminalis.<br />
<br />
Observe the periurethral vascular supply and the venous plexuses in the urethral crest.<br />
<br />
<peir-vm>UAB-Histology-00124</peir-vm><br />
<br />
=== Seminal Vesicles ===<br />
<br />
The seminal vesicles are paired saccular organs each in the form of a convoluted tube. They lie posterior to the prostate and their secretions, rich in fructose, enter the ejaculatory ducts just below the ampulla of the ductus deferens. The three layers of the gland are a mucosa, a muscularis and an adventitia (= fibrosa). The single lumen is irregular and branching with numerous lateral outpocketings.<br />
<br />
==== Slide 237, Seminal Vesicle (H&E) ====<br />
<br />
Observe that the gland appears to possess numerous lumina. Actually only one continuous cavity is present, but when the numerous convolutions of the gland are cut in one plane, separate cavities appear to be present.<br />
<br />
Note the complicated folding of the mucosa in which thin primary folds often exhibit secondary and tertiary branching.<br />
<br />
The muscularis contains an inner circular and an outer longitudinal layer of smooth muscle; two layers are not easily distinguishable in a section. <br />
<br />
The adventitia or fibrosa is rich in elastic fibers. It contains large blood vessels, nerves, and blends with other connective tissue surrounding the gland. One or more ganglia may be present.<br />
<br />
With high power study the mucosa on slide 237. The epithelium may appear to be simple cuboidal or low columnar, but the presence of basal cells makes it a low pseudostratified epithelium. The lining cells are secretory. A few granules may be present, or vacuoles may occur where they were dissolved away. Look for yellow or brownish lipochrome pigment in the surface cells. This pigment gives a yellowish tinge to the viscid secretions coming from these glands. The pigment begins to appear at puberty and increases with age. Beneath the epithelium is a basement membrane and a thin lamina propria with abundant elastic fibers. <br />
<br />
<peir-vm>UAB-Histology-00237</peir-vm><br />
<br />
=== Bulbourethral Gland ===<br />
<br />
==== Slide 238, Bulbourethral Gland (Masson) ====<br />
<br />
Scan Slide 238, Bulbourethral gland (Masson) to observe that:<br />
<br />
The irregular lobules of this compound tubuloalveolar gland are separated from each other by connective tissue septa that extend inward from a thin capsule.<br />
<br />
At the periphery of the gland and also in the connective tissue septa between some of the lobules can be seen skeletal muscle fibers.<br />
<br />
Interlobular excretory ducts lie within some of the larger connective tissue septa. (See e below)<br />
<br />
With high power study the parenchyma consisting of pale secretory cells, usually cuboidal to columnar in shape. They resemble mucous cells. The nucleus tends to be flattened at the base of the cells; however, some are rounded, others are oval and vertically oriented. The varying shapes of the nuclei probably indicate different states of secretory activity exhibited by the cells at the time of fixation. A mucus-like discharge from these glands lubricates the urethra during sexual simulation.<br />
<br />
In the smaller ducts of the bulbourethral gland the epithelium is simple and quite variable ranging from low cuboidal to columnar. The large excretory ducts are lined by stratified columnar epithelium that may contain patches of secreting cells. Smooth muscle fibers can usually be found among the connective tissue fibers surrounding these ducts and also in other regions of the connective tissue septa.<br />
<br />
<peir-vm>UAB-Histology-00238</peir-vm><br />
<br />
== Penis ==<br />
<br />
=== Slide 284, Penis (H&E) ===<br />
<br />
The penis is composed of erectile tissue and contains the section of penile urethra. The erectile tissue is composed of two dorsal cylinders (corpora cavernosa) and a smaller central ventral cylinder (corpus spongiosum) through which the penile urethra runs. These cylinders are each surrounded by a dense fibrocollagenous sheath, the tunica albuginea. The erectile tissues are essentially interconnecting vascular spaces which are empty when the penis is flaccid but which become engorged with blood during an erection. <br />
<br />
The blood supply to the penis is provided by the dorsal and the deep arteries. From the deep arteries arise arteries supplying the tunica albuginea, and the helicine arteries, which supply the erectile tissue. The helicine arteries form convoluted vessels in the flaccid penis but during erection they straighten and dilate, filling the corpora with blood. This filling effect is partly due to closure of the arteriovenous shunts existing between the helicine arteries and deep veins, which constitute the normal route of helicine artery blood flow in the flaccid state. Parasympathetic nerve discharges cause the closure, leading to diversion of the helicine artery blood into the cavernous spaces, while increased pressure in the corpora compresses the thin-walled veins, preventing emptying. After ejaculation the parasympathetic stimulation ceases, the arteriovenous shunts open and blood passes from the corpora into the veins.<br />
<br />
At the distal end of the penis the corpus spongiosum terminates on the glans penis, which is covered with non-keratinizing squamous epithelium containing sebaceous glands. The penile urethra opens to the exterior at the meatus at the centre of the glans penis<br />
<br />
For most of its length the penile urethra is lined by non-secreting columnar epithelium into which small mucus glands embedded in the corpus spongiosum drain. Within the glans penis, however, the urethra dilates (navicular fossa) and becomes lined by non-keratinizing stratified squamous epithelium identical to that covering the glans.<br />
<br />
<peir-vm>UAB-Histology-00284</peir-vm><br />
<br />
{{Template:Histologic}}<br />
<br />
[[Category:Histologic]]</div>Matthew Andersonhttps://peir.path.uab.edu/index.php?title=Histologic:Chapter_15&diff=3244Histologic:Chapter 152014-07-18T05:46:30Z<p>Matthew Anderson: /* Urinary Bladder */</p>
<hr />
<div>== Kidney ==<br />
[[File:HistologicChapter15Kidney.jpg|thumb|200px|Kidney]]<br />
A good knowledge of normal kidney histology is essential for the understanding of various diseases of the kidney. <br />
<br />
=== Slide 117, Kidney (Masson) ===<br />
[[File:HistologicChapter15KidneyLabelled.jpg|thumb|200px|Kidney]]<br />
Observe Slide 117, kidney (Masson) with the unaided eye to distinguish the lighter stained medulla from the more peripheral and darker-staining cortex. Now, with low and medium powers of the microscope identify:<br />
<br />
*The thin, fibrous capsule of the kidney. Scan the entire slide to observe that the only prominent connective tissue fibers within the kidney are in association with blood vessels.<br />
<br />
*The cortex containing the renal corpuscles.<br />
<br />
*The medulla in which renal corpuscles are lacking.<br />
<br />
*The larger blood vessels at the corticomedullary junction. These are arcuate arteries and veins.<br />
<br />
Study the cortex of the kidney for details of its organization. On Slide 114, Slide 116, Slide 117, and Slide 118 identify:<br />
<br />
Pars radiata (medullary rays) are columns of straight tubules extending from the cortex into the medulla and from the medulla into the cortex. <br />
<br />
The straight segments of the proximal and distal tubules and the straight collecting tubules are located here.<br />
<br />
Pars convoluta (cortical labyrinths) areas occupy the region between pars radiata.<br />
<br />
Within the pars convoluta can be found renal corpuscles, proximal convoluted tubules (PCT), distal convoluted tubules (DCT), and blood vessels (the interlobular arteries and veins and the afferent and efferent arterioles). A kidney lobule consists of a pars radiata and “half” of each adjoining pars convoluta.<br />
<br />
Learn to distinguish the PCT from the DCT. With the light microscope the straight portion of the proximal tubule is histologically similar to the PCT and the straight portion of the distal tubule is similar to the DCT.<br />
<br />
Proximal convoluted tubule (PCT). The PCT may be up to 14 mm in length. This is more than twice as long as the average DCT, which is about 5 mm long. Thus, one sees more sections through PCT in any given region of the pars convoluta than through DCT.<br />
<br />
*The PCT stains darker than the DCT.<br />
<br />
*The PCT cells are larger and the cytoplasm is more granular than the cells of the DCT. This is due to the large number of mitochondria in the cytoplasm of the PCT cells.<br />
<br />
*The cell boundaries of the PCT are less distinct than the DCT because the membranes of the PCT cells are more highly interdigitated with the membranes of neighboring cells. And the PCT is larger in cross section than the DCT.<br />
<br />
*The apical surface of the PCT exhibits microvilli, about 1.2 μm in length, which form a brush border when observed with the light microscope. This border disintegrates quickly when postmortem changes set in. A brush border is lacking on cells of the DCT although the EM demonstrates the presence of a few microvilli.<br />
<br />
*The cells of the PCT are low columnar to pyramidal; those of the DCT are more cuboidal in shape.<br />
<br />
<peir-vm>UAB-Histology-00117</peir-vm><br />
<br />
==== Slide 114, Kidney ====<br />
<peir-vm>UAB-Histology-00114</peir-vm><br />
==== Slide 116, Kidney ====<br />
<peir-vm>UAB-Histology-00116</peir-vm><br />
<br />
=== Slide 118, Kidney (PASH) ===<br />
[[File:HistologicChapter15Glomerulus.jpg|thumb|200px|Glomerulus]]<br />
[[File:HistologicChapter15Kidney4.jpg|thumb|200px|Kidney]]<br />
[[File:HistologicChapter15Kidney5.jpg|thumb|200px|Kidney]]<br />
The renal corpuscles on Slide 118, Kidney (PASH) are to be studied in detail.<br />
<br />
First, with low power, become oriented to the section on Slide 118. This is a tangential section through the cortex of the kidney. Thus, renal corpuscles are found throughout the. Note that tubules in the pars radiata are cut in cross section and appear to be grouped into bundles surrounded (or bordered) by pars convoluta. We will study these tubules in detail later.<br />
<br />
On high power study several renal corpuscles on Slide 118. A renal corpuscle ranges from 150 to 250 μm in diameter. It consists of a tuft of capillaries called the glomerulus and a surrounding epithelial capsule called the glomerular capsule (Bowman’s capsule). This latter structure has an outer layer of simple squamous epithelial cells with a basement membrane. The cells and basement membrane form the parietal layer of Bowman’s capsule, which surrounds Bowman’s space or the urinary space. A layer of visceral epithelial cells covers the glomerular basement membrane. The cells of this highly modified epithelial layer are called podocytes because of numerous foot-like processes (pedicels) that they possess. The space between the visceral and parietal layers of Bowman’s capsule is termed Bowman’s space or urinary space within which the glomerular filtrate is collected and passes into the PCT. The parietal epithelial cells are continuous with the neck of the PCT and with the visceral layer at the vascular pole.<br />
<br />
Identify:<br />
<br />
*The simple squamous epithelial cells of the parietal layer.<br />
*The basement membrane on which the cells lie.<br />
*The urinary space.<br />
<br />
The glomerulus is a specialized bed of capillaries connecting an afferent arteriole with an efferent arteriole at the vascular pole of the renal corpuscle. The urinary pole of the renal corpuscle where the glomerular filtrate passes into the PCT usually lies opposite the vascular pole. <br />
<br />
Find, if present, a renal corpuscle sectioned so as to demonstrate both the vascular and urinary poles.<br />
<br />
Study several glomeruli in detail.<br />
<br />
*A glomerulus appears lobulated since the looped capillaries from a major capillary branch are grouped together. About 5-8 major capillary trunks (lobules) are formed in each glomerulus. Up to 50 capillary loops may be present.<br />
<br />
*Anastomoses occur between capillaries of the same lobule and of different lobules.<br />
<br />
*The afferent arteriole supplying blood to the glomerulus is usually larger than the efferent arteriole.<br />
<br />
*The endothelial cells lining the capillary lumen are fairly large, attenuated, flattened cells with nuclei bulging into the lumen. The fenestrated endothelium has numerous pores that vary from 50 to 100 nm in diameters. These endothelial cells are only partially surrounded by a basement membrane that is about 300 nm thick in adults. The capillaries of each lobule wind around a common axis that appears as a cellular stalk of mesangial cells and mesangial matrix. Basement membrane is lacking between the capillary endothelium and the stalk of the capillary lobule occupied by the mesangial cells and mesangial matrix. Hence, instead of surrounding the entire lumen of a capillary loop, the basement membrane is reflected onto adjacent capillary loops. The mesangial cells are located inside of the basement membrane of the capillary lobule, and they are in direct contact with the endothelial cells where basement membrane material is lacking.<br />
<br />
*Identify the nuclei of endothelial cells, mesangial cells lying in mesangial matrix, and the nuclei of podocytes.<br />
<br />
On Slide 118 select, an “open appearing” capillary loop cut in cross section, lying towards the outer edge of a glomerulus and within which a nucleus can be seen bulging into the lumen. This is the nucleus of an endothelial cell. The nuclei tend to lie on the wall of the capillary loop nearest the central axis.<br />
<br />
Find a slightly darker staining nucleus, about the same size as the endothelial nucleus, embedded in the denser, darkly stained PAS-positive material. This is a mesangial cell nucleus and the PAS-positive staining material is mesangial matrix. The mesangial cell lies to the inner side of the basement membrane. Electron micrographs show that the mesangial cells are in direct contact with the endothelial cells. The mesangial matrix produced by the mesangial cells is a basement membrane-like material that increases with age and in certain disease states such as diabetic nephropathy and glomerulonephritis.<br />
<br />
Identify slightly larger, slightly paler staining nuclei lying outside the basement membrane. They are podocyte nuclei. The interdigitated cytoplasmic extensions of the podocytes, which line the outside of the basement membrane, can be seen only with the electron microscope.<br />
<br />
Filtration Barrier. In order for substances in the blood to reach the urinary space as glomerular filtrate they must pass through the filtration barrier. This important barrier includes the endothelium of the capillary, basal lamina and slit pores between adjacent pedicles (foot processes) of the podocytes. The slit pores are about 250 nm in diameter and they are bridges by a thin diaphragm called the filtration slit membrane.<br />
<br />
Identify on Slide 117 the endothelial cells of the glomerular capillary, the mesangial cells and mesangial matrix, and the podocytes. On this section stained with Masson’s stain the basement membrane of the glomerulus appears as a very thin blue line. The mesangial matrix is readily identified as the purplish-staining material between capillaries.<br />
<br />
Juxtaglomerular apparatus. On Slide 118 attempt to find a juxtaglomerular apparatus where the distal tubule comes into close association with the afferent glomerular arteriole at the vascular pole of each Bowman’s capsule. This composite structure consists of the macula densa of the distal tubule, lacis cells (extraglomerular mesangial cells) and juxtaglomerular cells (JG cells). The latter cells are modified smooth muscle cells in the tunica media of the afferent arteriole. These secretory, epithelioid cells replace the smooth muscle cells of the media only in the localized region of the juxtaglomerular apparatus. The JG cells are separated from the cells forming the macula densa only by a basal lamina. The JG cells are important since they secrete renin.<br />
<br />
The macula densa is identified as being an area of tall, slender cells on the side of the distal tubule adjacent to the afferent arteriole. Since the cells are narrow, the nuclei appear closely packed together, and with the light microscope the area appears denser than surrounding areas (macula densa = “dense spot”). The function of these cells is to monitor sodium in the distal tubule and “pass” this information to the JG cells to alter their secretory activity.<br />
<br />
The lacis cells are small agranular cells lying in a triangular area bounded by the afferent and efferent arterioles and the macula densa. The lacis cells are embedded in a dense network of basement membranes. They are continuous with the mesangium of the capillary stalk. The specific function of lacis cells is not well understood, although it has been associated with the secretion of erythropoietin.<br />
<br />
Study the tubules in the medulla of the kidney on Slides 114, 116, and 117. A straight collecting tubule lying in the pars radiata of the cortex receives 7 to 10 arched collecting tubules as it passes into the outer zone of the medulla. Continuing into the inner zone of the medulla the straight collecting tubules unite with other similar tubules to form large papillary ducts. These open into the minor calyces at the area cribrosa of a renal papilla. Papillary ducts are not found in the outer zone of the medulla. The straight collecting tubules have a diameter of about 40μm as compared with a diameter of 200 μm for the papillary ducts.<br />
<br />
On Slide 117 identify straight collecting tubules in the medulla. They exhibit a lining of large pale staining, simple columnar cells with well-defined cell boundaries. <br />
<br />
Identify the smallest tubules cut in cross section in the medulla. These are the thin segments of the loops of Henle. Only the juxtamedullary nephrons have thin segments extending deep into the medulla. The thin segments of Henle’s loop are easily confused with capillaries or venules. They are composed of a single layer of flattened epithelial cells having round to ovoid nuclei that tend to bulge into the lumen. The cells sit on a basement membrane. The overall diameter of the segment is about 15μm, and cross sections of them usually contain 3 to 5 nuclei. Remember that the loops of Henle are made up of both thick and thin segments. The thick segments form descending and ascending limbs. An abrupt change occurs in the epithelium where the thick segments meet the thin segments.<br />
<br />
Return to Slide 118 and identify the collecting ducts in the pars radiata. They have many nuclei in cross section and have distinctly visible cell boundaries. In the pars convoluta the proximal convoluted tubules are easily identified by the PAS-positive staining of their brush border. The straight portion of the proximal tubule in the pars radiata appears similar. The straight portions of the distal tubules (thick ascending segment of Henle’s loop) located in the pars radiata appear to have undergone more postmortem change than other parts of the tubule. The straight distal tubules exhibit cells that are somewhat disrupted and pulled free of the basement membrane. Many cells appear to be “floating” within the lumen of the tubule. Identify the straight proximal and distal tubule.<br />
<br />
Blood supply<br />
<br />
The circulation of blood through the kidney is rather complex and should be studied in your textbook before attempting to understand it from slides. Only a few aspects of the overall circulation can be seen on any one microscopic slide.<br />
<br />
On Slide 117 identify the arcuate arteries and the arcuate veins at the corticomedullary junction. The arteries are continuations (branches) of the larger interlobar arteries.<br />
<br />
Each arcuate artery gives off several interlobular arteries that pass perpendicularly through a pars convoluta to the surface of the kidney. Identify interlobular arteries on Slide 117; they are very small arteries or arterioles. Thin-walled interlobular veins (mostly venules) are seen adjacent to some of the interlobular arteries. The arteries and veins pass more or less through the middle of a pars convoluta. The area between two interlobular arteries and veins is a kidney lobule. On Slide 118 identify interlobular arteries cut in cross section and lying within a pars convoluta. A number of afferent glomerular arterioles are given off by the interlobular artery before it terminates as a capillary bed beneath the capsule of the kidney.<br />
<br />
On Slide 117 identify the erythrocytes in capillaries that are interspersed between the convoluted tubules. In the outer cortex, the capillaries originate from the efferent arterioles to form a peritubular plexus, which in the living condition appears to bathe the tubules in blood. The capillaries drain into cortical venules that empty into interlobular veins that accompany the interlobular arteries.<br />
<br />
The efferent arterioles leaving glomeruli near the medulla are relatively larger than the efferent arterioles in the outer cortex. They extend into the medulla as the arteriolae rectae spuriae. Pursuing a straight course in the medulla, these vessels give rise to capillary nets that extend deeply into the papillae. Veins called venae rectae return the blood to the arcuate veins. Collectively the blood supply of the medulla in which these thin-walled vessels make hairpin loops is called the vasa rectae.<br />
<br />
Interstitial connective tissue. The connective tissue of the kidney is not nearly as extensive as in other organs. Most of the prominent connective tissue is in association with blood vessels, lymphatics and nerves. The more delicate and looser connective tissue spreads through the renal parenchyma. It is more abundant in the medulla than in the cortex. This poorly developed interstitial tissue consists principally of reticular and collagenous fibers with associated fibroblasts and macrophages. Observe on Slide 117 (Masson) that the large blood vessels are invested with the densest connective tissue, the adventitia. Very delicate collagen fibers can be seen surrounding tubules in the medulla. They appear as a pale blue network. Reticular fibers also form a diffuse network around the tubules. Compare the amount of interstitial connective tissue in the medulla with the amount present around the convoluted tubules of the cortex. The interstitial diseases of the kidney form from or directly affect the interstitial tissue. In severe systemic infections, non- specific inflammatory changes can occur in the interstitium.<br />
<br />
The sinus of the kidney is the concave indentation or potential cavity on the hilus side of the kidney. It lies adjacent to kidney cortex of the renal columns and to medulla. It contains loose connective tissue and fat. In it are embedded branches of the renal artery and vein, lymphatics, nerves, minor calyces, major calyces and the renal pelvis.<br />
<br />
<peir-vm>UAB-Histology-00118</peir-vm><br />
<br />
=== Slide 92, Kidney, Ureter, Vessels ===<br />
<br />
Study Slide 92. Section through the sinus of the kidney showing several blood vessels, nerves, and a section of ureter, all embedded in loose connective and adipose tissue (H&E).<br />
<br />
<peir-vm>UAB-Histology-00092</peir-vm><br />
<br />
== Ureter and Urinary Bladder ==<br />
<br />
=== Ureter ===<br />
<br />
The ureters conduct urine from the kidneys to the bladder. They are about 12 inches long, course behind the peritoneum, and consist of three layers (a mucosa, a muscularis and a fibrosa).<br />
<br />
==== Slide 120, Ureter (Masson) ====<br />
<br />
Study Slide 120, Ureter (Masson), which is a cross section through the lower one-third of the ureter. At low and medium power observe:<br />
<br />
The mucosa consisting of transitional epithelium and a lamina propria. Note the stellate-shaped lumen formed by the folds of the lamina propria, the density of the lamina propria, and the thickness of the epithelium.<br />
<br />
The muscularis has three layers of smooth muscle since this section was taken from the lower one-third of the ureter. The upper two-thirds of the ureter has only two layers of smooth muscle in the muscularis. Identify, here, an inner longitudinal layer with fibers cut in cross section, the middle circular layer and an outer longitudinal layer. It is this outer layer that is the “extra layer” of the lower ureter. Note how the muscle bundles are separated by abundant connective tissue.<br />
<br />
Identify the fibrosa lying outside the muscularis. This loose connective tissue layer binds the ureter to adjoining structures. Observe the blood vessels running through the fibrosa, which also contains nerves, lymphatics and fat cells.<br />
<br />
<peir-vm>UAB-Histology-00120</peir-vm><br />
<br />
==== Slide 119, Ureter (H&E) ====<br />
<br />
Examine Slide 119, Ureter (H&E) under low and medium power for most of the features just studied on Slide 120. In addition, note that:<br />
<br />
*With H&E, the muscle layers do not contrast well with the connective tissue fibers. Hence, it is difficult to distinguish that the middle portion of the ureter from which this section was taken has only two muscle layers instead of three. These are an inner longitudinal layer and an outer circular layer. <br />
<br />
*Note the abundance of adipose tissue in the fibrosa. Identify the small arteries and veins occurring in this layer.<br />
<br />
*Study the mucosa of slide 119 at high power.<br />
<br />
It consists of a transitional epithelium of 5 to 6 cell layers thick. The surface cells of transitional epithelium, called cap cells, are larger and stain more darkly than the underlying cells. In some areas, the surface cells are stretched so as to appear almost squamous. The epithelium rests on a basement membrane, but the membrane is so thin that it is only identified with the electron microscope.<br />
<br />
The lamina propria is a rather dense-appearing connective tissue layer between the epithelium and the muscularis. It contains collagenous fibers, elastic fibers and connective tissue cells. In the Masson-stained ureter, Slide 120, venules and capillaries are more readily seen within the lamina propria than they are in Slide 119.<br />
<br />
Study the muscularis on Slide 119. This section is from the middle ureter that has only two layers of smooth muscle, an inner longitudinal and an outer circular layer. Contraction of the smooth muscle aids in passing the urine through the ureters.<br />
<br />
<peir-vm>UAB-Histology-00119</peir-vm><br />
<br />
=== Urinary Bladder ===<br />
[[File:HistologicChapter15Bladder.jpg|thumb|200px|Urinary Bladder]]<br />
The urinary bladder consists of a mucosa, a muscularis and an adventitia that is either a fibrosa (where it blends with the connective tissue of surrounding structures) or a serosa (found only on the superior surface where the bladder is covered with peritoneum).<br />
<br />
==== Slide 121, Urinary Bladder (H&E) ====<br />
<br />
Scan the slide with low and medium powers to identify the three major layers. <br />
<br />
Study the mucosa for details. A lining of transitional epithelium and underlying lamina propria form the mucosa. The empty bladder usually has a folded mucosa, the distended bladder a smooth one. Examine the epithelium in different regions of this section. In the relaxed bladder, as seen here, the epithelium is six or more cell layers thick; whereas in the distended bladder the epithelium is so stretched it appears to be only two or three cell layers thick. Recall that the epithelium is a special type of stratified epithelium that undergoes “transitional changes” to allow for the filling and emptying of the bladder.<br />
<br />
Examine the surface cells. Observe in some regions their dome-shaped apices, and how they appear to “cap” the smaller underlying cells. These cap cells are occasionally binucleated. They are stretched into a “squamous” layer in the distended bladder. The cells immediately beneath the surface cells are pear-shaped or flask-shaped and their apices fit into facet-like indentations on the underside of the surface cells. The basal layer cells undergo mitosis to replenish the surface cells sloughed off into the lumen of the urinary bladder.<br />
<br />
The luminal plasma membrane of the surface cells is thicker than most plasma membranes. This specialization, in conjunction with the superficial layer of cytoplasm containing numerous tonofilaments (microfilaments), serves to protect the epithelium from the hypertonicity of the urine, prevents urine resorption and acts as a barrier to the loss of water from the cells into the hypertonic urine.<br />
<br />
The connective tissue underlying the transitional epithelium is the lamina propria. It is mostly collagenous fibers in which some elastic networks occur. Lymphocytes wander through the lamina propria and an occasional solitary lymphatic nodule can be present (but it is unlikely that you will see one on our slides). Observe that the deeper region of the lamina propria gives rise to an extensive capillary bed beneath the epithelium.<br />
<br />
The muscularis of the bladder has three layers of smooth muscle indistinctly arranged into an inner longitudinal layer, a middle circular layer, and an outer longitudinal layer. The middle circular layer is the thickest but this may be difficult to identify on your slides, since the different muscle bundles tend to interlace and anastomose. Observe the abundant connective tissue that separates bundles of muscle. The muscularis has an abundant blood supply with an extensive capillary network.<br />
<br />
Adventitia. This section of bladder is covered by a serosa consisting of a surface mesothelium. <br />
<br />
<peir-vm>UAB-Histology-00121</peir-vm> <br />
<br />
{{Template:Histologic}}<br />
<br />
[[Category:Histologic]]</div>Matthew Andersonhttps://peir.path.uab.edu/index.php?title=File:HistologicChapter15Bladder.jpg&diff=3243File:HistologicChapter15Bladder.jpg2014-07-18T05:46:14Z<p>Matthew Anderson: </p>
<hr />
<div></div>Matthew Andersonhttps://peir.path.uab.edu/index.php?title=Histologic:Chapter_15&diff=3242Histologic:Chapter 152014-07-18T05:44:34Z<p>Matthew Anderson: /* Slide 118, Kidney (PASH) */</p>
<hr />
<div>== Kidney ==<br />
[[File:HistologicChapter15Kidney.jpg|thumb|200px|Kidney]]<br />
A good knowledge of normal kidney histology is essential for the understanding of various diseases of the kidney. <br />
<br />
=== Slide 117, Kidney (Masson) ===<br />
[[File:HistologicChapter15KidneyLabelled.jpg|thumb|200px|Kidney]]<br />
Observe Slide 117, kidney (Masson) with the unaided eye to distinguish the lighter stained medulla from the more peripheral and darker-staining cortex. Now, with low and medium powers of the microscope identify:<br />
<br />
*The thin, fibrous capsule of the kidney. Scan the entire slide to observe that the only prominent connective tissue fibers within the kidney are in association with blood vessels.<br />
<br />
*The cortex containing the renal corpuscles.<br />
<br />
*The medulla in which renal corpuscles are lacking.<br />
<br />
*The larger blood vessels at the corticomedullary junction. These are arcuate arteries and veins.<br />
<br />
Study the cortex of the kidney for details of its organization. On Slide 114, Slide 116, Slide 117, and Slide 118 identify:<br />
<br />
Pars radiata (medullary rays) are columns of straight tubules extending from the cortex into the medulla and from the medulla into the cortex. <br />
<br />
The straight segments of the proximal and distal tubules and the straight collecting tubules are located here.<br />
<br />
Pars convoluta (cortical labyrinths) areas occupy the region between pars radiata.<br />
<br />
Within the pars convoluta can be found renal corpuscles, proximal convoluted tubules (PCT), distal convoluted tubules (DCT), and blood vessels (the interlobular arteries and veins and the afferent and efferent arterioles). A kidney lobule consists of a pars radiata and “half” of each adjoining pars convoluta.<br />
<br />
Learn to distinguish the PCT from the DCT. With the light microscope the straight portion of the proximal tubule is histologically similar to the PCT and the straight portion of the distal tubule is similar to the DCT.<br />
<br />
Proximal convoluted tubule (PCT). The PCT may be up to 14 mm in length. This is more than twice as long as the average DCT, which is about 5 mm long. Thus, one sees more sections through PCT in any given region of the pars convoluta than through DCT.<br />
<br />
*The PCT stains darker than the DCT.<br />
<br />
*The PCT cells are larger and the cytoplasm is more granular than the cells of the DCT. This is due to the large number of mitochondria in the cytoplasm of the PCT cells.<br />
<br />
*The cell boundaries of the PCT are less distinct than the DCT because the membranes of the PCT cells are more highly interdigitated with the membranes of neighboring cells. And the PCT is larger in cross section than the DCT.<br />
<br />
*The apical surface of the PCT exhibits microvilli, about 1.2 μm in length, which form a brush border when observed with the light microscope. This border disintegrates quickly when postmortem changes set in. A brush border is lacking on cells of the DCT although the EM demonstrates the presence of a few microvilli.<br />
<br />
*The cells of the PCT are low columnar to pyramidal; those of the DCT are more cuboidal in shape.<br />
<br />
<peir-vm>UAB-Histology-00117</peir-vm><br />
<br />
==== Slide 114, Kidney ====<br />
<peir-vm>UAB-Histology-00114</peir-vm><br />
==== Slide 116, Kidney ====<br />
<peir-vm>UAB-Histology-00116</peir-vm><br />
<br />
=== Slide 118, Kidney (PASH) ===<br />
[[File:HistologicChapter15Glomerulus.jpg|thumb|200px|Glomerulus]]<br />
[[File:HistologicChapter15Kidney4.jpg|thumb|200px|Kidney]]<br />
[[File:HistologicChapter15Kidney5.jpg|thumb|200px|Kidney]]<br />
The renal corpuscles on Slide 118, Kidney (PASH) are to be studied in detail.<br />
<br />
First, with low power, become oriented to the section on Slide 118. This is a tangential section through the cortex of the kidney. Thus, renal corpuscles are found throughout the. Note that tubules in the pars radiata are cut in cross section and appear to be grouped into bundles surrounded (or bordered) by pars convoluta. We will study these tubules in detail later.<br />
<br />
On high power study several renal corpuscles on Slide 118. A renal corpuscle ranges from 150 to 250 μm in diameter. It consists of a tuft of capillaries called the glomerulus and a surrounding epithelial capsule called the glomerular capsule (Bowman’s capsule). This latter structure has an outer layer of simple squamous epithelial cells with a basement membrane. The cells and basement membrane form the parietal layer of Bowman’s capsule, which surrounds Bowman’s space or the urinary space. A layer of visceral epithelial cells covers the glomerular basement membrane. The cells of this highly modified epithelial layer are called podocytes because of numerous foot-like processes (pedicels) that they possess. The space between the visceral and parietal layers of Bowman’s capsule is termed Bowman’s space or urinary space within which the glomerular filtrate is collected and passes into the PCT. The parietal epithelial cells are continuous with the neck of the PCT and with the visceral layer at the vascular pole.<br />
<br />
Identify:<br />
<br />
*The simple squamous epithelial cells of the parietal layer.<br />
*The basement membrane on which the cells lie.<br />
*The urinary space.<br />
<br />
The glomerulus is a specialized bed of capillaries connecting an afferent arteriole with an efferent arteriole at the vascular pole of the renal corpuscle. The urinary pole of the renal corpuscle where the glomerular filtrate passes into the PCT usually lies opposite the vascular pole. <br />
<br />
Find, if present, a renal corpuscle sectioned so as to demonstrate both the vascular and urinary poles.<br />
<br />
Study several glomeruli in detail.<br />
<br />
*A glomerulus appears lobulated since the looped capillaries from a major capillary branch are grouped together. About 5-8 major capillary trunks (lobules) are formed in each glomerulus. Up to 50 capillary loops may be present.<br />
<br />
*Anastomoses occur between capillaries of the same lobule and of different lobules.<br />
<br />
*The afferent arteriole supplying blood to the glomerulus is usually larger than the efferent arteriole.<br />
<br />
*The endothelial cells lining the capillary lumen are fairly large, attenuated, flattened cells with nuclei bulging into the lumen. The fenestrated endothelium has numerous pores that vary from 50 to 100 nm in diameters. These endothelial cells are only partially surrounded by a basement membrane that is about 300 nm thick in adults. The capillaries of each lobule wind around a common axis that appears as a cellular stalk of mesangial cells and mesangial matrix. Basement membrane is lacking between the capillary endothelium and the stalk of the capillary lobule occupied by the mesangial cells and mesangial matrix. Hence, instead of surrounding the entire lumen of a capillary loop, the basement membrane is reflected onto adjacent capillary loops. The mesangial cells are located inside of the basement membrane of the capillary lobule, and they are in direct contact with the endothelial cells where basement membrane material is lacking.<br />
<br />
*Identify the nuclei of endothelial cells, mesangial cells lying in mesangial matrix, and the nuclei of podocytes.<br />
<br />
On Slide 118 select, an “open appearing” capillary loop cut in cross section, lying towards the outer edge of a glomerulus and within which a nucleus can be seen bulging into the lumen. This is the nucleus of an endothelial cell. The nuclei tend to lie on the wall of the capillary loop nearest the central axis.<br />
<br />
Find a slightly darker staining nucleus, about the same size as the endothelial nucleus, embedded in the denser, darkly stained PAS-positive material. This is a mesangial cell nucleus and the PAS-positive staining material is mesangial matrix. The mesangial cell lies to the inner side of the basement membrane. Electron micrographs show that the mesangial cells are in direct contact with the endothelial cells. The mesangial matrix produced by the mesangial cells is a basement membrane-like material that increases with age and in certain disease states such as diabetic nephropathy and glomerulonephritis.<br />
<br />
Identify slightly larger, slightly paler staining nuclei lying outside the basement membrane. They are podocyte nuclei. The interdigitated cytoplasmic extensions of the podocytes, which line the outside of the basement membrane, can be seen only with the electron microscope.<br />
<br />
Filtration Barrier. In order for substances in the blood to reach the urinary space as glomerular filtrate they must pass through the filtration barrier. This important barrier includes the endothelium of the capillary, basal lamina and slit pores between adjacent pedicles (foot processes) of the podocytes. The slit pores are about 250 nm in diameter and they are bridges by a thin diaphragm called the filtration slit membrane.<br />
<br />
Identify on Slide 117 the endothelial cells of the glomerular capillary, the mesangial cells and mesangial matrix, and the podocytes. On this section stained with Masson’s stain the basement membrane of the glomerulus appears as a very thin blue line. The mesangial matrix is readily identified as the purplish-staining material between capillaries.<br />
<br />
Juxtaglomerular apparatus. On Slide 118 attempt to find a juxtaglomerular apparatus where the distal tubule comes into close association with the afferent glomerular arteriole at the vascular pole of each Bowman’s capsule. This composite structure consists of the macula densa of the distal tubule, lacis cells (extraglomerular mesangial cells) and juxtaglomerular cells (JG cells). The latter cells are modified smooth muscle cells in the tunica media of the afferent arteriole. These secretory, epithelioid cells replace the smooth muscle cells of the media only in the localized region of the juxtaglomerular apparatus. The JG cells are separated from the cells forming the macula densa only by a basal lamina. The JG cells are important since they secrete renin.<br />
<br />
The macula densa is identified as being an area of tall, slender cells on the side of the distal tubule adjacent to the afferent arteriole. Since the cells are narrow, the nuclei appear closely packed together, and with the light microscope the area appears denser than surrounding areas (macula densa = “dense spot”). The function of these cells is to monitor sodium in the distal tubule and “pass” this information to the JG cells to alter their secretory activity.<br />
<br />
The lacis cells are small agranular cells lying in a triangular area bounded by the afferent and efferent arterioles and the macula densa. The lacis cells are embedded in a dense network of basement membranes. They are continuous with the mesangium of the capillary stalk. The specific function of lacis cells is not well understood, although it has been associated with the secretion of erythropoietin.<br />
<br />
Study the tubules in the medulla of the kidney on Slides 114, 116, and 117. A straight collecting tubule lying in the pars radiata of the cortex receives 7 to 10 arched collecting tubules as it passes into the outer zone of the medulla. Continuing into the inner zone of the medulla the straight collecting tubules unite with other similar tubules to form large papillary ducts. These open into the minor calyces at the area cribrosa of a renal papilla. Papillary ducts are not found in the outer zone of the medulla. The straight collecting tubules have a diameter of about 40μm as compared with a diameter of 200 μm for the papillary ducts.<br />
<br />
On Slide 117 identify straight collecting tubules in the medulla. They exhibit a lining of large pale staining, simple columnar cells with well-defined cell boundaries. <br />
<br />
Identify the smallest tubules cut in cross section in the medulla. These are the thin segments of the loops of Henle. Only the juxtamedullary nephrons have thin segments extending deep into the medulla. The thin segments of Henle’s loop are easily confused with capillaries or venules. They are composed of a single layer of flattened epithelial cells having round to ovoid nuclei that tend to bulge into the lumen. The cells sit on a basement membrane. The overall diameter of the segment is about 15μm, and cross sections of them usually contain 3 to 5 nuclei. Remember that the loops of Henle are made up of both thick and thin segments. The thick segments form descending and ascending limbs. An abrupt change occurs in the epithelium where the thick segments meet the thin segments.<br />
<br />
Return to Slide 118 and identify the collecting ducts in the pars radiata. They have many nuclei in cross section and have distinctly visible cell boundaries. In the pars convoluta the proximal convoluted tubules are easily identified by the PAS-positive staining of their brush border. The straight portion of the proximal tubule in the pars radiata appears similar. The straight portions of the distal tubules (thick ascending segment of Henle’s loop) located in the pars radiata appear to have undergone more postmortem change than other parts of the tubule. The straight distal tubules exhibit cells that are somewhat disrupted and pulled free of the basement membrane. Many cells appear to be “floating” within the lumen of the tubule. Identify the straight proximal and distal tubule.<br />
<br />
Blood supply<br />
<br />
The circulation of blood through the kidney is rather complex and should be studied in your textbook before attempting to understand it from slides. Only a few aspects of the overall circulation can be seen on any one microscopic slide.<br />
<br />
On Slide 117 identify the arcuate arteries and the arcuate veins at the corticomedullary junction. The arteries are continuations (branches) of the larger interlobar arteries.<br />
<br />
Each arcuate artery gives off several interlobular arteries that pass perpendicularly through a pars convoluta to the surface of the kidney. Identify interlobular arteries on Slide 117; they are very small arteries or arterioles. Thin-walled interlobular veins (mostly venules) are seen adjacent to some of the interlobular arteries. The arteries and veins pass more or less through the middle of a pars convoluta. The area between two interlobular arteries and veins is a kidney lobule. On Slide 118 identify interlobular arteries cut in cross section and lying within a pars convoluta. A number of afferent glomerular arterioles are given off by the interlobular artery before it terminates as a capillary bed beneath the capsule of the kidney.<br />
<br />
On Slide 117 identify the erythrocytes in capillaries that are interspersed between the convoluted tubules. In the outer cortex, the capillaries originate from the efferent arterioles to form a peritubular plexus, which in the living condition appears to bathe the tubules in blood. The capillaries drain into cortical venules that empty into interlobular veins that accompany the interlobular arteries.<br />
<br />
The efferent arterioles leaving glomeruli near the medulla are relatively larger than the efferent arterioles in the outer cortex. They extend into the medulla as the arteriolae rectae spuriae. Pursuing a straight course in the medulla, these vessels give rise to capillary nets that extend deeply into the papillae. Veins called venae rectae return the blood to the arcuate veins. Collectively the blood supply of the medulla in which these thin-walled vessels make hairpin loops is called the vasa rectae.<br />
<br />
Interstitial connective tissue. The connective tissue of the kidney is not nearly as extensive as in other organs. Most of the prominent connective tissue is in association with blood vessels, lymphatics and nerves. The more delicate and looser connective tissue spreads through the renal parenchyma. It is more abundant in the medulla than in the cortex. This poorly developed interstitial tissue consists principally of reticular and collagenous fibers with associated fibroblasts and macrophages. Observe on Slide 117 (Masson) that the large blood vessels are invested with the densest connective tissue, the adventitia. Very delicate collagen fibers can be seen surrounding tubules in the medulla. They appear as a pale blue network. Reticular fibers also form a diffuse network around the tubules. Compare the amount of interstitial connective tissue in the medulla with the amount present around the convoluted tubules of the cortex. The interstitial diseases of the kidney form from or directly affect the interstitial tissue. In severe systemic infections, non- specific inflammatory changes can occur in the interstitium.<br />
<br />
The sinus of the kidney is the concave indentation or potential cavity on the hilus side of the kidney. It lies adjacent to kidney cortex of the renal columns and to medulla. It contains loose connective tissue and fat. In it are embedded branches of the renal artery and vein, lymphatics, nerves, minor calyces, major calyces and the renal pelvis.<br />
<br />
<peir-vm>UAB-Histology-00118</peir-vm><br />
<br />
=== Slide 92, Kidney, Ureter, Vessels ===<br />
<br />
Study Slide 92. Section through the sinus of the kidney showing several blood vessels, nerves, and a section of ureter, all embedded in loose connective and adipose tissue (H&E).<br />
<br />
<peir-vm>UAB-Histology-00092</peir-vm><br />
<br />
== Ureter and Urinary Bladder ==<br />
<br />
=== Ureter ===<br />
<br />
The ureters conduct urine from the kidneys to the bladder. They are about 12 inches long, course behind the peritoneum, and consist of three layers (a mucosa, a muscularis and a fibrosa).<br />
<br />
==== Slide 120, Ureter (Masson) ====<br />
<br />
Study Slide 120, Ureter (Masson), which is a cross section through the lower one-third of the ureter. At low and medium power observe:<br />
<br />
The mucosa consisting of transitional epithelium and a lamina propria. Note the stellate-shaped lumen formed by the folds of the lamina propria, the density of the lamina propria, and the thickness of the epithelium.<br />
<br />
The muscularis has three layers of smooth muscle since this section was taken from the lower one-third of the ureter. The upper two-thirds of the ureter has only two layers of smooth muscle in the muscularis. Identify, here, an inner longitudinal layer with fibers cut in cross section, the middle circular layer and an outer longitudinal layer. It is this outer layer that is the “extra layer” of the lower ureter. Note how the muscle bundles are separated by abundant connective tissue.<br />
<br />
Identify the fibrosa lying outside the muscularis. This loose connective tissue layer binds the ureter to adjoining structures. Observe the blood vessels running through the fibrosa, which also contains nerves, lymphatics and fat cells.<br />
<br />
<peir-vm>UAB-Histology-00120</peir-vm><br />
<br />
==== Slide 119, Ureter (H&E) ====<br />
<br />
Examine Slide 119, Ureter (H&E) under low and medium power for most of the features just studied on Slide 120. In addition, note that:<br />
<br />
*With H&E, the muscle layers do not contrast well with the connective tissue fibers. Hence, it is difficult to distinguish that the middle portion of the ureter from which this section was taken has only two muscle layers instead of three. These are an inner longitudinal layer and an outer circular layer. <br />
<br />
*Note the abundance of adipose tissue in the fibrosa. Identify the small arteries and veins occurring in this layer.<br />
<br />
*Study the mucosa of slide 119 at high power.<br />
<br />
It consists of a transitional epithelium of 5 to 6 cell layers thick. The surface cells of transitional epithelium, called cap cells, are larger and stain more darkly than the underlying cells. In some areas, the surface cells are stretched so as to appear almost squamous. The epithelium rests on a basement membrane, but the membrane is so thin that it is only identified with the electron microscope.<br />
<br />
The lamina propria is a rather dense-appearing connective tissue layer between the epithelium and the muscularis. It contains collagenous fibers, elastic fibers and connective tissue cells. In the Masson-stained ureter, Slide 120, venules and capillaries are more readily seen within the lamina propria than they are in Slide 119.<br />
<br />
Study the muscularis on Slide 119. This section is from the middle ureter that has only two layers of smooth muscle, an inner longitudinal and an outer circular layer. Contraction of the smooth muscle aids in passing the urine through the ureters.<br />
<br />
<peir-vm>UAB-Histology-00119</peir-vm><br />
<br />
=== Urinary Bladder ===<br />
<br />
The urinary bladder consists of a mucosa, a muscularis and an adventitia that is either a fibrosa (where it blends with the connective tissue of surrounding structures) or a serosa (found only on the superior surface where the bladder is covered with peritoneum).<br />
<br />
==== Slide 121, Urinary Bladder (H&E) ====<br />
<br />
Scan the slide with low and medium powers to identify the three major layers. <br />
<br />
Study the mucosa for details. A lining of transitional epithelium and underlying lamina propria form the mucosa. The empty bladder usually has a folded mucosa, the distended bladder a smooth one. Examine the epithelium in different regions of this section. In the relaxed bladder, as seen here, the epithelium is six or more cell layers thick; whereas in the distended bladder the epithelium is so stretched it appears to be only two or three cell layers thick. Recall that the epithelium is a special type of stratified epithelium that undergoes “transitional changes” to allow for the filling and emptying of the bladder.<br />
<br />
Examine the surface cells. Observe in some regions their dome-shaped apices, and how they appear to “cap” the smaller underlying cells. These cap cells are occasionally binucleated. They are stretched into a “squamous” layer in the distended bladder. The cells immediately beneath the surface cells are pear-shaped or flask-shaped and their apices fit into facet-like indentations on the underside of the surface cells. The basal layer cells undergo mitosis to replenish the surface cells sloughed off into the lumen of the urinary bladder.<br />
<br />
The luminal plasma membrane of the surface cells is thicker than most plasma membranes. This specialization, in conjunction with the superficial layer of cytoplasm containing numerous tonofilaments (microfilaments), serves to protect the epithelium from the hypertonicity of the urine, prevents urine resorption and acts as a barrier to the loss of water from the cells into the hypertonic urine.<br />
<br />
The connective tissue underlying the transitional epithelium is the lamina propria. It is mostly collagenous fibers in which some elastic networks occur. Lymphocytes wander through the lamina propria and an occasional solitary lymphatic nodule can be present (but it is unlikely that you will see one on our slides). Observe that the deeper region of the lamina propria gives rise to an extensive capillary bed beneath the epithelium.<br />
<br />
The muscularis of the bladder has three layers of smooth muscle indistinctly arranged into an inner longitudinal layer, a middle circular layer, and an outer longitudinal layer. The middle circular layer is the thickest but this may be difficult to identify on your slides, since the different muscle bundles tend to interlace and anastomose. Observe the abundant connective tissue that separates bundles of muscle. The muscularis has an abundant blood supply with an extensive capillary network.<br />
<br />
Adventitia. This section of bladder is covered by a serosa consisting of a surface mesothelium. <br />
<br />
<peir-vm>UAB-Histology-00121</peir-vm> <br />
<br />
{{Template:Histologic}}<br />
<br />
[[Category:Histologic]]</div>Matthew Andersonhttps://peir.path.uab.edu/index.php?title=File:HistologicChapter15Kidney5.jpg&diff=3241File:HistologicChapter15Kidney5.jpg2014-07-18T05:44:15Z<p>Matthew Anderson: </p>
<hr />
<div></div>Matthew Andersonhttps://peir.path.uab.edu/index.php?title=Histologic:Chapter_15&diff=3240Histologic:Chapter 152014-07-18T05:43:17Z<p>Matthew Anderson: /* Slide 118, Kidney (PASH) */</p>
<hr />
<div>== Kidney ==<br />
[[File:HistologicChapter15Kidney.jpg|thumb|200px|Kidney]]<br />
A good knowledge of normal kidney histology is essential for the understanding of various diseases of the kidney. <br />
<br />
=== Slide 117, Kidney (Masson) ===<br />
[[File:HistologicChapter15KidneyLabelled.jpg|thumb|200px|Kidney]]<br />
Observe Slide 117, kidney (Masson) with the unaided eye to distinguish the lighter stained medulla from the more peripheral and darker-staining cortex. Now, with low and medium powers of the microscope identify:<br />
<br />
*The thin, fibrous capsule of the kidney. Scan the entire slide to observe that the only prominent connective tissue fibers within the kidney are in association with blood vessels.<br />
<br />
*The cortex containing the renal corpuscles.<br />
<br />
*The medulla in which renal corpuscles are lacking.<br />
<br />
*The larger blood vessels at the corticomedullary junction. These are arcuate arteries and veins.<br />
<br />
Study the cortex of the kidney for details of its organization. On Slide 114, Slide 116, Slide 117, and Slide 118 identify:<br />
<br />
Pars radiata (medullary rays) are columns of straight tubules extending from the cortex into the medulla and from the medulla into the cortex. <br />
<br />
The straight segments of the proximal and distal tubules and the straight collecting tubules are located here.<br />
<br />
Pars convoluta (cortical labyrinths) areas occupy the region between pars radiata.<br />
<br />
Within the pars convoluta can be found renal corpuscles, proximal convoluted tubules (PCT), distal convoluted tubules (DCT), and blood vessels (the interlobular arteries and veins and the afferent and efferent arterioles). A kidney lobule consists of a pars radiata and “half” of each adjoining pars convoluta.<br />
<br />
Learn to distinguish the PCT from the DCT. With the light microscope the straight portion of the proximal tubule is histologically similar to the PCT and the straight portion of the distal tubule is similar to the DCT.<br />
<br />
Proximal convoluted tubule (PCT). The PCT may be up to 14 mm in length. This is more than twice as long as the average DCT, which is about 5 mm long. Thus, one sees more sections through PCT in any given region of the pars convoluta than through DCT.<br />
<br />
*The PCT stains darker than the DCT.<br />
<br />
*The PCT cells are larger and the cytoplasm is more granular than the cells of the DCT. This is due to the large number of mitochondria in the cytoplasm of the PCT cells.<br />
<br />
*The cell boundaries of the PCT are less distinct than the DCT because the membranes of the PCT cells are more highly interdigitated with the membranes of neighboring cells. And the PCT is larger in cross section than the DCT.<br />
<br />
*The apical surface of the PCT exhibits microvilli, about 1.2 μm in length, which form a brush border when observed with the light microscope. This border disintegrates quickly when postmortem changes set in. A brush border is lacking on cells of the DCT although the EM demonstrates the presence of a few microvilli.<br />
<br />
*The cells of the PCT are low columnar to pyramidal; those of the DCT are more cuboidal in shape.<br />
<br />
<peir-vm>UAB-Histology-00117</peir-vm><br />
<br />
==== Slide 114, Kidney ====<br />
<peir-vm>UAB-Histology-00114</peir-vm><br />
==== Slide 116, Kidney ====<br />
<peir-vm>UAB-Histology-00116</peir-vm><br />
<br />
=== Slide 118, Kidney (PASH) ===<br />
[[File:HistologicChapter15Glomerulus.jpg|thumb|200px|Glomerulus]]<br />
[[File:HistologicChapter15Kidney4.jpg|thumb|200px|Kidney]]<br />
The renal corpuscles on Slide 118, Kidney (PASH) are to be studied in detail.<br />
<br />
First, with low power, become oriented to the section on Slide 118. This is a tangential section through the cortex of the kidney. Thus, renal corpuscles are found throughout the. Note that tubules in the pars radiata are cut in cross section and appear to be grouped into bundles surrounded (or bordered) by pars convoluta. We will study these tubules in detail later.<br />
<br />
On high power study several renal corpuscles on Slide 118. A renal corpuscle ranges from 150 to 250 μm in diameter. It consists of a tuft of capillaries called the glomerulus and a surrounding epithelial capsule called the glomerular capsule (Bowman’s capsule). This latter structure has an outer layer of simple squamous epithelial cells with a basement membrane. The cells and basement membrane form the parietal layer of Bowman’s capsule, which surrounds Bowman’s space or the urinary space. A layer of visceral epithelial cells covers the glomerular basement membrane. The cells of this highly modified epithelial layer are called podocytes because of numerous foot-like processes (pedicels) that they possess. The space between the visceral and parietal layers of Bowman’s capsule is termed Bowman’s space or urinary space within which the glomerular filtrate is collected and passes into the PCT. The parietal epithelial cells are continuous with the neck of the PCT and with the visceral layer at the vascular pole.<br />
<br />
Identify:<br />
<br />
*The simple squamous epithelial cells of the parietal layer.<br />
*The basement membrane on which the cells lie.<br />
*The urinary space.<br />
<br />
The glomerulus is a specialized bed of capillaries connecting an afferent arteriole with an efferent arteriole at the vascular pole of the renal corpuscle. The urinary pole of the renal corpuscle where the glomerular filtrate passes into the PCT usually lies opposite the vascular pole. <br />
<br />
Find, if present, a renal corpuscle sectioned so as to demonstrate both the vascular and urinary poles.<br />
<br />
Study several glomeruli in detail.<br />
<br />
*A glomerulus appears lobulated since the looped capillaries from a major capillary branch are grouped together. About 5-8 major capillary trunks (lobules) are formed in each glomerulus. Up to 50 capillary loops may be present.<br />
<br />
*Anastomoses occur between capillaries of the same lobule and of different lobules.<br />
<br />
*The afferent arteriole supplying blood to the glomerulus is usually larger than the efferent arteriole.<br />
<br />
*The endothelial cells lining the capillary lumen are fairly large, attenuated, flattened cells with nuclei bulging into the lumen. The fenestrated endothelium has numerous pores that vary from 50 to 100 nm in diameters. These endothelial cells are only partially surrounded by a basement membrane that is about 300 nm thick in adults. The capillaries of each lobule wind around a common axis that appears as a cellular stalk of mesangial cells and mesangial matrix. Basement membrane is lacking between the capillary endothelium and the stalk of the capillary lobule occupied by the mesangial cells and mesangial matrix. Hence, instead of surrounding the entire lumen of a capillary loop, the basement membrane is reflected onto adjacent capillary loops. The mesangial cells are located inside of the basement membrane of the capillary lobule, and they are in direct contact with the endothelial cells where basement membrane material is lacking.<br />
<br />
*Identify the nuclei of endothelial cells, mesangial cells lying in mesangial matrix, and the nuclei of podocytes.<br />
<br />
On Slide 118 select, an “open appearing” capillary loop cut in cross section, lying towards the outer edge of a glomerulus and within which a nucleus can be seen bulging into the lumen. This is the nucleus of an endothelial cell. The nuclei tend to lie on the wall of the capillary loop nearest the central axis.<br />
<br />
Find a slightly darker staining nucleus, about the same size as the endothelial nucleus, embedded in the denser, darkly stained PAS-positive material. This is a mesangial cell nucleus and the PAS-positive staining material is mesangial matrix. The mesangial cell lies to the inner side of the basement membrane. Electron micrographs show that the mesangial cells are in direct contact with the endothelial cells. The mesangial matrix produced by the mesangial cells is a basement membrane-like material that increases with age and in certain disease states such as diabetic nephropathy and glomerulonephritis.<br />
<br />
Identify slightly larger, slightly paler staining nuclei lying outside the basement membrane. They are podocyte nuclei. The interdigitated cytoplasmic extensions of the podocytes, which line the outside of the basement membrane, can be seen only with the electron microscope.<br />
<br />
Filtration Barrier. In order for substances in the blood to reach the urinary space as glomerular filtrate they must pass through the filtration barrier. This important barrier includes the endothelium of the capillary, basal lamina and slit pores between adjacent pedicles (foot processes) of the podocytes. The slit pores are about 250 nm in diameter and they are bridges by a thin diaphragm called the filtration slit membrane.<br />
<br />
Identify on Slide 117 the endothelial cells of the glomerular capillary, the mesangial cells and mesangial matrix, and the podocytes. On this section stained with Masson’s stain the basement membrane of the glomerulus appears as a very thin blue line. The mesangial matrix is readily identified as the purplish-staining material between capillaries.<br />
<br />
Juxtaglomerular apparatus. On Slide 118 attempt to find a juxtaglomerular apparatus where the distal tubule comes into close association with the afferent glomerular arteriole at the vascular pole of each Bowman’s capsule. This composite structure consists of the macula densa of the distal tubule, lacis cells (extraglomerular mesangial cells) and juxtaglomerular cells (JG cells). The latter cells are modified smooth muscle cells in the tunica media of the afferent arteriole. These secretory, epithelioid cells replace the smooth muscle cells of the media only in the localized region of the juxtaglomerular apparatus. The JG cells are separated from the cells forming the macula densa only by a basal lamina. The JG cells are important since they secrete renin.<br />
<br />
The macula densa is identified as being an area of tall, slender cells on the side of the distal tubule adjacent to the afferent arteriole. Since the cells are narrow, the nuclei appear closely packed together, and with the light microscope the area appears denser than surrounding areas (macula densa = “dense spot”). The function of these cells is to monitor sodium in the distal tubule and “pass” this information to the JG cells to alter their secretory activity.<br />
<br />
The lacis cells are small agranular cells lying in a triangular area bounded by the afferent and efferent arterioles and the macula densa. The lacis cells are embedded in a dense network of basement membranes. They are continuous with the mesangium of the capillary stalk. The specific function of lacis cells is not well understood, although it has been associated with the secretion of erythropoietin.<br />
<br />
Study the tubules in the medulla of the kidney on Slides 114, 116, and 117. A straight collecting tubule lying in the pars radiata of the cortex receives 7 to 10 arched collecting tubules as it passes into the outer zone of the medulla. Continuing into the inner zone of the medulla the straight collecting tubules unite with other similar tubules to form large papillary ducts. These open into the minor calyces at the area cribrosa of a renal papilla. Papillary ducts are not found in the outer zone of the medulla. The straight collecting tubules have a diameter of about 40μm as compared with a diameter of 200 μm for the papillary ducts.<br />
<br />
On Slide 117 identify straight collecting tubules in the medulla. They exhibit a lining of large pale staining, simple columnar cells with well-defined cell boundaries. <br />
<br />
Identify the smallest tubules cut in cross section in the medulla. These are the thin segments of the loops of Henle. Only the juxtamedullary nephrons have thin segments extending deep into the medulla. The thin segments of Henle’s loop are easily confused with capillaries or venules. They are composed of a single layer of flattened epithelial cells having round to ovoid nuclei that tend to bulge into the lumen. The cells sit on a basement membrane. The overall diameter of the segment is about 15μm, and cross sections of them usually contain 3 to 5 nuclei. Remember that the loops of Henle are made up of both thick and thin segments. The thick segments form descending and ascending limbs. An abrupt change occurs in the epithelium where the thick segments meet the thin segments.<br />
<br />
Return to Slide 118 and identify the collecting ducts in the pars radiata. They have many nuclei in cross section and have distinctly visible cell boundaries. In the pars convoluta the proximal convoluted tubules are easily identified by the PAS-positive staining of their brush border. The straight portion of the proximal tubule in the pars radiata appears similar. The straight portions of the distal tubules (thick ascending segment of Henle’s loop) located in the pars radiata appear to have undergone more postmortem change than other parts of the tubule. The straight distal tubules exhibit cells that are somewhat disrupted and pulled free of the basement membrane. Many cells appear to be “floating” within the lumen of the tubule. Identify the straight proximal and distal tubule.<br />
<br />
Blood supply<br />
<br />
The circulation of blood through the kidney is rather complex and should be studied in your textbook before attempting to understand it from slides. Only a few aspects of the overall circulation can be seen on any one microscopic slide.<br />
<br />
On Slide 117 identify the arcuate arteries and the arcuate veins at the corticomedullary junction. The arteries are continuations (branches) of the larger interlobar arteries.<br />
<br />
Each arcuate artery gives off several interlobular arteries that pass perpendicularly through a pars convoluta to the surface of the kidney. Identify interlobular arteries on Slide 117; they are very small arteries or arterioles. Thin-walled interlobular veins (mostly venules) are seen adjacent to some of the interlobular arteries. The arteries and veins pass more or less through the middle of a pars convoluta. The area between two interlobular arteries and veins is a kidney lobule. On Slide 118 identify interlobular arteries cut in cross section and lying within a pars convoluta. A number of afferent glomerular arterioles are given off by the interlobular artery before it terminates as a capillary bed beneath the capsule of the kidney.<br />
<br />
On Slide 117 identify the erythrocytes in capillaries that are interspersed between the convoluted tubules. In the outer cortex, the capillaries originate from the efferent arterioles to form a peritubular plexus, which in the living condition appears to bathe the tubules in blood. The capillaries drain into cortical venules that empty into interlobular veins that accompany the interlobular arteries.<br />
<br />
The efferent arterioles leaving glomeruli near the medulla are relatively larger than the efferent arterioles in the outer cortex. They extend into the medulla as the arteriolae rectae spuriae. Pursuing a straight course in the medulla, these vessels give rise to capillary nets that extend deeply into the papillae. Veins called venae rectae return the blood to the arcuate veins. Collectively the blood supply of the medulla in which these thin-walled vessels make hairpin loops is called the vasa rectae.<br />
<br />
Interstitial connective tissue. The connective tissue of the kidney is not nearly as extensive as in other organs. Most of the prominent connective tissue is in association with blood vessels, lymphatics and nerves. The more delicate and looser connective tissue spreads through the renal parenchyma. It is more abundant in the medulla than in the cortex. This poorly developed interstitial tissue consists principally of reticular and collagenous fibers with associated fibroblasts and macrophages. Observe on Slide 117 (Masson) that the large blood vessels are invested with the densest connective tissue, the adventitia. Very delicate collagen fibers can be seen surrounding tubules in the medulla. They appear as a pale blue network. Reticular fibers also form a diffuse network around the tubules. Compare the amount of interstitial connective tissue in the medulla with the amount present around the convoluted tubules of the cortex. The interstitial diseases of the kidney form from or directly affect the interstitial tissue. In severe systemic infections, non- specific inflammatory changes can occur in the interstitium.<br />
<br />
The sinus of the kidney is the concave indentation or potential cavity on the hilus side of the kidney. It lies adjacent to kidney cortex of the renal columns and to medulla. It contains loose connective tissue and fat. In it are embedded branches of the renal artery and vein, lymphatics, nerves, minor calyces, major calyces and the renal pelvis.<br />
<br />
<peir-vm>UAB-Histology-00118</peir-vm><br />
<br />
=== Slide 92, Kidney, Ureter, Vessels ===<br />
<br />
Study Slide 92. Section through the sinus of the kidney showing several blood vessels, nerves, and a section of ureter, all embedded in loose connective and adipose tissue (H&E).<br />
<br />
<peir-vm>UAB-Histology-00092</peir-vm><br />
<br />
== Ureter and Urinary Bladder ==<br />
<br />
=== Ureter ===<br />
<br />
The ureters conduct urine from the kidneys to the bladder. They are about 12 inches long, course behind the peritoneum, and consist of three layers (a mucosa, a muscularis and a fibrosa).<br />
<br />
==== Slide 120, Ureter (Masson) ====<br />
<br />
Study Slide 120, Ureter (Masson), which is a cross section through the lower one-third of the ureter. At low and medium power observe:<br />
<br />
The mucosa consisting of transitional epithelium and a lamina propria. Note the stellate-shaped lumen formed by the folds of the lamina propria, the density of the lamina propria, and the thickness of the epithelium.<br />
<br />
The muscularis has three layers of smooth muscle since this section was taken from the lower one-third of the ureter. The upper two-thirds of the ureter has only two layers of smooth muscle in the muscularis. Identify, here, an inner longitudinal layer with fibers cut in cross section, the middle circular layer and an outer longitudinal layer. It is this outer layer that is the “extra layer” of the lower ureter. Note how the muscle bundles are separated by abundant connective tissue.<br />
<br />
Identify the fibrosa lying outside the muscularis. This loose connective tissue layer binds the ureter to adjoining structures. Observe the blood vessels running through the fibrosa, which also contains nerves, lymphatics and fat cells.<br />
<br />
<peir-vm>UAB-Histology-00120</peir-vm><br />
<br />
==== Slide 119, Ureter (H&E) ====<br />
<br />
Examine Slide 119, Ureter (H&E) under low and medium power for most of the features just studied on Slide 120. In addition, note that:<br />
<br />
*With H&E, the muscle layers do not contrast well with the connective tissue fibers. Hence, it is difficult to distinguish that the middle portion of the ureter from which this section was taken has only two muscle layers instead of three. These are an inner longitudinal layer and an outer circular layer. <br />
<br />
*Note the abundance of adipose tissue in the fibrosa. Identify the small arteries and veins occurring in this layer.<br />
<br />
*Study the mucosa of slide 119 at high power.<br />
<br />
It consists of a transitional epithelium of 5 to 6 cell layers thick. The surface cells of transitional epithelium, called cap cells, are larger and stain more darkly than the underlying cells. In some areas, the surface cells are stretched so as to appear almost squamous. The epithelium rests on a basement membrane, but the membrane is so thin that it is only identified with the electron microscope.<br />
<br />
The lamina propria is a rather dense-appearing connective tissue layer between the epithelium and the muscularis. It contains collagenous fibers, elastic fibers and connective tissue cells. In the Masson-stained ureter, Slide 120, venules and capillaries are more readily seen within the lamina propria than they are in Slide 119.<br />
<br />
Study the muscularis on Slide 119. This section is from the middle ureter that has only two layers of smooth muscle, an inner longitudinal and an outer circular layer. Contraction of the smooth muscle aids in passing the urine through the ureters.<br />
<br />
<peir-vm>UAB-Histology-00119</peir-vm><br />
<br />
=== Urinary Bladder ===<br />
<br />
The urinary bladder consists of a mucosa, a muscularis and an adventitia that is either a fibrosa (where it blends with the connective tissue of surrounding structures) or a serosa (found only on the superior surface where the bladder is covered with peritoneum).<br />
<br />
==== Slide 121, Urinary Bladder (H&E) ====<br />
<br />
Scan the slide with low and medium powers to identify the three major layers. <br />
<br />
Study the mucosa for details. A lining of transitional epithelium and underlying lamina propria form the mucosa. The empty bladder usually has a folded mucosa, the distended bladder a smooth one. Examine the epithelium in different regions of this section. In the relaxed bladder, as seen here, the epithelium is six or more cell layers thick; whereas in the distended bladder the epithelium is so stretched it appears to be only two or three cell layers thick. Recall that the epithelium is a special type of stratified epithelium that undergoes “transitional changes” to allow for the filling and emptying of the bladder.<br />
<br />
Examine the surface cells. Observe in some regions their dome-shaped apices, and how they appear to “cap” the smaller underlying cells. These cap cells are occasionally binucleated. They are stretched into a “squamous” layer in the distended bladder. The cells immediately beneath the surface cells are pear-shaped or flask-shaped and their apices fit into facet-like indentations on the underside of the surface cells. The basal layer cells undergo mitosis to replenish the surface cells sloughed off into the lumen of the urinary bladder.<br />
<br />
The luminal plasma membrane of the surface cells is thicker than most plasma membranes. This specialization, in conjunction with the superficial layer of cytoplasm containing numerous tonofilaments (microfilaments), serves to protect the epithelium from the hypertonicity of the urine, prevents urine resorption and acts as a barrier to the loss of water from the cells into the hypertonic urine.<br />
<br />
The connective tissue underlying the transitional epithelium is the lamina propria. It is mostly collagenous fibers in which some elastic networks occur. Lymphocytes wander through the lamina propria and an occasional solitary lymphatic nodule can be present (but it is unlikely that you will see one on our slides). Observe that the deeper region of the lamina propria gives rise to an extensive capillary bed beneath the epithelium.<br />
<br />
The muscularis of the bladder has three layers of smooth muscle indistinctly arranged into an inner longitudinal layer, a middle circular layer, and an outer longitudinal layer. The middle circular layer is the thickest but this may be difficult to identify on your slides, since the different muscle bundles tend to interlace and anastomose. Observe the abundant connective tissue that separates bundles of muscle. The muscularis has an abundant blood supply with an extensive capillary network.<br />
<br />
Adventitia. This section of bladder is covered by a serosa consisting of a surface mesothelium. <br />
<br />
<peir-vm>UAB-Histology-00121</peir-vm> <br />
<br />
{{Template:Histologic}}<br />
<br />
[[Category:Histologic]]</div>Matthew Andersonhttps://peir.path.uab.edu/index.php?title=File:HistologicChapter15Kidney4.jpg&diff=3239File:HistologicChapter15Kidney4.jpg2014-07-18T05:43:03Z<p>Matthew Anderson: </p>
<hr />
<div></div>Matthew Andersonhttps://peir.path.uab.edu/index.php?title=Histologic:Chapter_15&diff=3238Histologic:Chapter 152014-07-18T05:41:56Z<p>Matthew Anderson: /* Slide 118, Kidney (PASH) */</p>
<hr />
<div>== Kidney ==<br />
[[File:HistologicChapter15Kidney.jpg|thumb|200px|Kidney]]<br />
A good knowledge of normal kidney histology is essential for the understanding of various diseases of the kidney. <br />
<br />
=== Slide 117, Kidney (Masson) ===<br />
[[File:HistologicChapter15KidneyLabelled.jpg|thumb|200px|Kidney]]<br />
Observe Slide 117, kidney (Masson) with the unaided eye to distinguish the lighter stained medulla from the more peripheral and darker-staining cortex. Now, with low and medium powers of the microscope identify:<br />
<br />
*The thin, fibrous capsule of the kidney. Scan the entire slide to observe that the only prominent connective tissue fibers within the kidney are in association with blood vessels.<br />
<br />
*The cortex containing the renal corpuscles.<br />
<br />
*The medulla in which renal corpuscles are lacking.<br />
<br />
*The larger blood vessels at the corticomedullary junction. These are arcuate arteries and veins.<br />
<br />
Study the cortex of the kidney for details of its organization. On Slide 114, Slide 116, Slide 117, and Slide 118 identify:<br />
<br />
Pars radiata (medullary rays) are columns of straight tubules extending from the cortex into the medulla and from the medulla into the cortex. <br />
<br />
The straight segments of the proximal and distal tubules and the straight collecting tubules are located here.<br />
<br />
Pars convoluta (cortical labyrinths) areas occupy the region between pars radiata.<br />
<br />
Within the pars convoluta can be found renal corpuscles, proximal convoluted tubules (PCT), distal convoluted tubules (DCT), and blood vessels (the interlobular arteries and veins and the afferent and efferent arterioles). A kidney lobule consists of a pars radiata and “half” of each adjoining pars convoluta.<br />
<br />
Learn to distinguish the PCT from the DCT. With the light microscope the straight portion of the proximal tubule is histologically similar to the PCT and the straight portion of the distal tubule is similar to the DCT.<br />
<br />
Proximal convoluted tubule (PCT). The PCT may be up to 14 mm in length. This is more than twice as long as the average DCT, which is about 5 mm long. Thus, one sees more sections through PCT in any given region of the pars convoluta than through DCT.<br />
<br />
*The PCT stains darker than the DCT.<br />
<br />
*The PCT cells are larger and the cytoplasm is more granular than the cells of the DCT. This is due to the large number of mitochondria in the cytoplasm of the PCT cells.<br />
<br />
*The cell boundaries of the PCT are less distinct than the DCT because the membranes of the PCT cells are more highly interdigitated with the membranes of neighboring cells. And the PCT is larger in cross section than the DCT.<br />
<br />
*The apical surface of the PCT exhibits microvilli, about 1.2 μm in length, which form a brush border when observed with the light microscope. This border disintegrates quickly when postmortem changes set in. A brush border is lacking on cells of the DCT although the EM demonstrates the presence of a few microvilli.<br />
<br />
*The cells of the PCT are low columnar to pyramidal; those of the DCT are more cuboidal in shape.<br />
<br />
<peir-vm>UAB-Histology-00117</peir-vm><br />
<br />
==== Slide 114, Kidney ====<br />
<peir-vm>UAB-Histology-00114</peir-vm><br />
==== Slide 116, Kidney ====<br />
<peir-vm>UAB-Histology-00116</peir-vm><br />
<br />
=== Slide 118, Kidney (PASH) ===<br />
[[File:HistologicChapter15Glomerulus.jpg|thumb|200px|Glomerulus]]<br />
The renal corpuscles on Slide 118, Kidney (PASH) are to be studied in detail.<br />
<br />
First, with low power, become oriented to the section on Slide 118. This is a tangential section through the cortex of the kidney. Thus, renal corpuscles are found throughout the. Note that tubules in the pars radiata are cut in cross section and appear to be grouped into bundles surrounded (or bordered) by pars convoluta. We will study these tubules in detail later.<br />
<br />
On high power study several renal corpuscles on Slide 118. A renal corpuscle ranges from 150 to 250 μm in diameter. It consists of a tuft of capillaries called the glomerulus and a surrounding epithelial capsule called the glomerular capsule (Bowman’s capsule). This latter structure has an outer layer of simple squamous epithelial cells with a basement membrane. The cells and basement membrane form the parietal layer of Bowman’s capsule, which surrounds Bowman’s space or the urinary space. A layer of visceral epithelial cells covers the glomerular basement membrane. The cells of this highly modified epithelial layer are called podocytes because of numerous foot-like processes (pedicels) that they possess. The space between the visceral and parietal layers of Bowman’s capsule is termed Bowman’s space or urinary space within which the glomerular filtrate is collected and passes into the PCT. The parietal epithelial cells are continuous with the neck of the PCT and with the visceral layer at the vascular pole.<br />
<br />
Identify:<br />
<br />
*The simple squamous epithelial cells of the parietal layer.<br />
*The basement membrane on which the cells lie.<br />
*The urinary space.<br />
<br />
The glomerulus is a specialized bed of capillaries connecting an afferent arteriole with an efferent arteriole at the vascular pole of the renal corpuscle. The urinary pole of the renal corpuscle where the glomerular filtrate passes into the PCT usually lies opposite the vascular pole. <br />
<br />
Find, if present, a renal corpuscle sectioned so as to demonstrate both the vascular and urinary poles.<br />
<br />
Study several glomeruli in detail.<br />
<br />
*A glomerulus appears lobulated since the looped capillaries from a major capillary branch are grouped together. About 5-8 major capillary trunks (lobules) are formed in each glomerulus. Up to 50 capillary loops may be present.<br />
<br />
*Anastomoses occur between capillaries of the same lobule and of different lobules.<br />
<br />
*The afferent arteriole supplying blood to the glomerulus is usually larger than the efferent arteriole.<br />
<br />
*The endothelial cells lining the capillary lumen are fairly large, attenuated, flattened cells with nuclei bulging into the lumen. The fenestrated endothelium has numerous pores that vary from 50 to 100 nm in diameters. These endothelial cells are only partially surrounded by a basement membrane that is about 300 nm thick in adults. The capillaries of each lobule wind around a common axis that appears as a cellular stalk of mesangial cells and mesangial matrix. Basement membrane is lacking between the capillary endothelium and the stalk of the capillary lobule occupied by the mesangial cells and mesangial matrix. Hence, instead of surrounding the entire lumen of a capillary loop, the basement membrane is reflected onto adjacent capillary loops. The mesangial cells are located inside of the basement membrane of the capillary lobule, and they are in direct contact with the endothelial cells where basement membrane material is lacking.<br />
<br />
*Identify the nuclei of endothelial cells, mesangial cells lying in mesangial matrix, and the nuclei of podocytes.<br />
<br />
On Slide 118 select, an “open appearing” capillary loop cut in cross section, lying towards the outer edge of a glomerulus and within which a nucleus can be seen bulging into the lumen. This is the nucleus of an endothelial cell. The nuclei tend to lie on the wall of the capillary loop nearest the central axis.<br />
<br />
Find a slightly darker staining nucleus, about the same size as the endothelial nucleus, embedded in the denser, darkly stained PAS-positive material. This is a mesangial cell nucleus and the PAS-positive staining material is mesangial matrix. The mesangial cell lies to the inner side of the basement membrane. Electron micrographs show that the mesangial cells are in direct contact with the endothelial cells. The mesangial matrix produced by the mesangial cells is a basement membrane-like material that increases with age and in certain disease states such as diabetic nephropathy and glomerulonephritis.<br />
<br />
Identify slightly larger, slightly paler staining nuclei lying outside the basement membrane. They are podocyte nuclei. The interdigitated cytoplasmic extensions of the podocytes, which line the outside of the basement membrane, can be seen only with the electron microscope.<br />
<br />
Filtration Barrier. In order for substances in the blood to reach the urinary space as glomerular filtrate they must pass through the filtration barrier. This important barrier includes the endothelium of the capillary, basal lamina and slit pores between adjacent pedicles (foot processes) of the podocytes. The slit pores are about 250 nm in diameter and they are bridges by a thin diaphragm called the filtration slit membrane.<br />
<br />
Identify on Slide 117 the endothelial cells of the glomerular capillary, the mesangial cells and mesangial matrix, and the podocytes. On this section stained with Masson’s stain the basement membrane of the glomerulus appears as a very thin blue line. The mesangial matrix is readily identified as the purplish-staining material between capillaries.<br />
<br />
Juxtaglomerular apparatus. On Slide 118 attempt to find a juxtaglomerular apparatus where the distal tubule comes into close association with the afferent glomerular arteriole at the vascular pole of each Bowman’s capsule. This composite structure consists of the macula densa of the distal tubule, lacis cells (extraglomerular mesangial cells) and juxtaglomerular cells (JG cells). The latter cells are modified smooth muscle cells in the tunica media of the afferent arteriole. These secretory, epithelioid cells replace the smooth muscle cells of the media only in the localized region of the juxtaglomerular apparatus. The JG cells are separated from the cells forming the macula densa only by a basal lamina. The JG cells are important since they secrete renin.<br />
<br />
The macula densa is identified as being an area of tall, slender cells on the side of the distal tubule adjacent to the afferent arteriole. Since the cells are narrow, the nuclei appear closely packed together, and with the light microscope the area appears denser than surrounding areas (macula densa = “dense spot”). The function of these cells is to monitor sodium in the distal tubule and “pass” this information to the JG cells to alter their secretory activity.<br />
<br />
The lacis cells are small agranular cells lying in a triangular area bounded by the afferent and efferent arterioles and the macula densa. The lacis cells are embedded in a dense network of basement membranes. They are continuous with the mesangium of the capillary stalk. The specific function of lacis cells is not well understood, although it has been associated with the secretion of erythropoietin.<br />
<br />
Study the tubules in the medulla of the kidney on Slides 114, 116, and 117. A straight collecting tubule lying in the pars radiata of the cortex receives 7 to 10 arched collecting tubules as it passes into the outer zone of the medulla. Continuing into the inner zone of the medulla the straight collecting tubules unite with other similar tubules to form large papillary ducts. These open into the minor calyces at the area cribrosa of a renal papilla. Papillary ducts are not found in the outer zone of the medulla. The straight collecting tubules have a diameter of about 40μm as compared with a diameter of 200 μm for the papillary ducts.<br />
<br />
On Slide 117 identify straight collecting tubules in the medulla. They exhibit a lining of large pale staining, simple columnar cells with well-defined cell boundaries. <br />
<br />
Identify the smallest tubules cut in cross section in the medulla. These are the thin segments of the loops of Henle. Only the juxtamedullary nephrons have thin segments extending deep into the medulla. The thin segments of Henle’s loop are easily confused with capillaries or venules. They are composed of a single layer of flattened epithelial cells having round to ovoid nuclei that tend to bulge into the lumen. The cells sit on a basement membrane. The overall diameter of the segment is about 15μm, and cross sections of them usually contain 3 to 5 nuclei. Remember that the loops of Henle are made up of both thick and thin segments. The thick segments form descending and ascending limbs. An abrupt change occurs in the epithelium where the thick segments meet the thin segments.<br />
<br />
Return to Slide 118 and identify the collecting ducts in the pars radiata. They have many nuclei in cross section and have distinctly visible cell boundaries. In the pars convoluta the proximal convoluted tubules are easily identified by the PAS-positive staining of their brush border. The straight portion of the proximal tubule in the pars radiata appears similar. The straight portions of the distal tubules (thick ascending segment of Henle’s loop) located in the pars radiata appear to have undergone more postmortem change than other parts of the tubule. The straight distal tubules exhibit cells that are somewhat disrupted and pulled free of the basement membrane. Many cells appear to be “floating” within the lumen of the tubule. Identify the straight proximal and distal tubule.<br />
<br />
Blood supply<br />
<br />
The circulation of blood through the kidney is rather complex and should be studied in your textbook before attempting to understand it from slides. Only a few aspects of the overall circulation can be seen on any one microscopic slide.<br />
<br />
On Slide 117 identify the arcuate arteries and the arcuate veins at the corticomedullary junction. The arteries are continuations (branches) of the larger interlobar arteries.<br />
<br />
Each arcuate artery gives off several interlobular arteries that pass perpendicularly through a pars convoluta to the surface of the kidney. Identify interlobular arteries on Slide 117; they are very small arteries or arterioles. Thin-walled interlobular veins (mostly venules) are seen adjacent to some of the interlobular arteries. The arteries and veins pass more or less through the middle of a pars convoluta. The area between two interlobular arteries and veins is a kidney lobule. On Slide 118 identify interlobular arteries cut in cross section and lying within a pars convoluta. A number of afferent glomerular arterioles are given off by the interlobular artery before it terminates as a capillary bed beneath the capsule of the kidney.<br />
<br />
On Slide 117 identify the erythrocytes in capillaries that are interspersed between the convoluted tubules. In the outer cortex, the capillaries originate from the efferent arterioles to form a peritubular plexus, which in the living condition appears to bathe the tubules in blood. The capillaries drain into cortical venules that empty into interlobular veins that accompany the interlobular arteries.<br />
<br />
The efferent arterioles leaving glomeruli near the medulla are relatively larger than the efferent arterioles in the outer cortex. They extend into the medulla as the arteriolae rectae spuriae. Pursuing a straight course in the medulla, these vessels give rise to capillary nets that extend deeply into the papillae. Veins called venae rectae return the blood to the arcuate veins. Collectively the blood supply of the medulla in which these thin-walled vessels make hairpin loops is called the vasa rectae.<br />
<br />
Interstitial connective tissue. The connective tissue of the kidney is not nearly as extensive as in other organs. Most of the prominent connective tissue is in association with blood vessels, lymphatics and nerves. The more delicate and looser connective tissue spreads through the renal parenchyma. It is more abundant in the medulla than in the cortex. This poorly developed interstitial tissue consists principally of reticular and collagenous fibers with associated fibroblasts and macrophages. Observe on Slide 117 (Masson) that the large blood vessels are invested with the densest connective tissue, the adventitia. Very delicate collagen fibers can be seen surrounding tubules in the medulla. They appear as a pale blue network. Reticular fibers also form a diffuse network around the tubules. Compare the amount of interstitial connective tissue in the medulla with the amount present around the convoluted tubules of the cortex. The interstitial diseases of the kidney form from or directly affect the interstitial tissue. In severe systemic infections, non- specific inflammatory changes can occur in the interstitium.<br />
<br />
The sinus of the kidney is the concave indentation or potential cavity on the hilus side of the kidney. It lies adjacent to kidney cortex of the renal columns and to medulla. It contains loose connective tissue and fat. In it are embedded branches of the renal artery and vein, lymphatics, nerves, minor calyces, major calyces and the renal pelvis.<br />
<br />
<peir-vm>UAB-Histology-00118</peir-vm><br />
<br />
=== Slide 92, Kidney, Ureter, Vessels ===<br />
<br />
Study Slide 92. Section through the sinus of the kidney showing several blood vessels, nerves, and a section of ureter, all embedded in loose connective and adipose tissue (H&E).<br />
<br />
<peir-vm>UAB-Histology-00092</peir-vm><br />
<br />
== Ureter and Urinary Bladder ==<br />
<br />
=== Ureter ===<br />
<br />
The ureters conduct urine from the kidneys to the bladder. They are about 12 inches long, course behind the peritoneum, and consist of three layers (a mucosa, a muscularis and a fibrosa).<br />
<br />
==== Slide 120, Ureter (Masson) ====<br />
<br />
Study Slide 120, Ureter (Masson), which is a cross section through the lower one-third of the ureter. At low and medium power observe:<br />
<br />
The mucosa consisting of transitional epithelium and a lamina propria. Note the stellate-shaped lumen formed by the folds of the lamina propria, the density of the lamina propria, and the thickness of the epithelium.<br />
<br />
The muscularis has three layers of smooth muscle since this section was taken from the lower one-third of the ureter. The upper two-thirds of the ureter has only two layers of smooth muscle in the muscularis. Identify, here, an inner longitudinal layer with fibers cut in cross section, the middle circular layer and an outer longitudinal layer. It is this outer layer that is the “extra layer” of the lower ureter. Note how the muscle bundles are separated by abundant connective tissue.<br />
<br />
Identify the fibrosa lying outside the muscularis. This loose connective tissue layer binds the ureter to adjoining structures. Observe the blood vessels running through the fibrosa, which also contains nerves, lymphatics and fat cells.<br />
<br />
<peir-vm>UAB-Histology-00120</peir-vm><br />
<br />
==== Slide 119, Ureter (H&E) ====<br />
<br />
Examine Slide 119, Ureter (H&E) under low and medium power for most of the features just studied on Slide 120. In addition, note that:<br />
<br />
*With H&E, the muscle layers do not contrast well with the connective tissue fibers. Hence, it is difficult to distinguish that the middle portion of the ureter from which this section was taken has only two muscle layers instead of three. These are an inner longitudinal layer and an outer circular layer. <br />
<br />
*Note the abundance of adipose tissue in the fibrosa. Identify the small arteries and veins occurring in this layer.<br />
<br />
*Study the mucosa of slide 119 at high power.<br />
<br />
It consists of a transitional epithelium of 5 to 6 cell layers thick. The surface cells of transitional epithelium, called cap cells, are larger and stain more darkly than the underlying cells. In some areas, the surface cells are stretched so as to appear almost squamous. The epithelium rests on a basement membrane, but the membrane is so thin that it is only identified with the electron microscope.<br />
<br />
The lamina propria is a rather dense-appearing connective tissue layer between the epithelium and the muscularis. It contains collagenous fibers, elastic fibers and connective tissue cells. In the Masson-stained ureter, Slide 120, venules and capillaries are more readily seen within the lamina propria than they are in Slide 119.<br />
<br />
Study the muscularis on Slide 119. This section is from the middle ureter that has only two layers of smooth muscle, an inner longitudinal and an outer circular layer. Contraction of the smooth muscle aids in passing the urine through the ureters.<br />
<br />
<peir-vm>UAB-Histology-00119</peir-vm><br />
<br />
=== Urinary Bladder ===<br />
<br />
The urinary bladder consists of a mucosa, a muscularis and an adventitia that is either a fibrosa (where it blends with the connective tissue of surrounding structures) or a serosa (found only on the superior surface where the bladder is covered with peritoneum).<br />
<br />
==== Slide 121, Urinary Bladder (H&E) ====<br />
<br />
Scan the slide with low and medium powers to identify the three major layers. <br />
<br />
Study the mucosa for details. A lining of transitional epithelium and underlying lamina propria form the mucosa. The empty bladder usually has a folded mucosa, the distended bladder a smooth one. Examine the epithelium in different regions of this section. In the relaxed bladder, as seen here, the epithelium is six or more cell layers thick; whereas in the distended bladder the epithelium is so stretched it appears to be only two or three cell layers thick. Recall that the epithelium is a special type of stratified epithelium that undergoes “transitional changes” to allow for the filling and emptying of the bladder.<br />
<br />
Examine the surface cells. Observe in some regions their dome-shaped apices, and how they appear to “cap” the smaller underlying cells. These cap cells are occasionally binucleated. They are stretched into a “squamous” layer in the distended bladder. The cells immediately beneath the surface cells are pear-shaped or flask-shaped and their apices fit into facet-like indentations on the underside of the surface cells. The basal layer cells undergo mitosis to replenish the surface cells sloughed off into the lumen of the urinary bladder.<br />
<br />
The luminal plasma membrane of the surface cells is thicker than most plasma membranes. This specialization, in conjunction with the superficial layer of cytoplasm containing numerous tonofilaments (microfilaments), serves to protect the epithelium from the hypertonicity of the urine, prevents urine resorption and acts as a barrier to the loss of water from the cells into the hypertonic urine.<br />
<br />
The connective tissue underlying the transitional epithelium is the lamina propria. It is mostly collagenous fibers in which some elastic networks occur. Lymphocytes wander through the lamina propria and an occasional solitary lymphatic nodule can be present (but it is unlikely that you will see one on our slides). Observe that the deeper region of the lamina propria gives rise to an extensive capillary bed beneath the epithelium.<br />
<br />
The muscularis of the bladder has three layers of smooth muscle indistinctly arranged into an inner longitudinal layer, a middle circular layer, and an outer longitudinal layer. The middle circular layer is the thickest but this may be difficult to identify on your slides, since the different muscle bundles tend to interlace and anastomose. Observe the abundant connective tissue that separates bundles of muscle. The muscularis has an abundant blood supply with an extensive capillary network.<br />
<br />
Adventitia. This section of bladder is covered by a serosa consisting of a surface mesothelium. <br />
<br />
<peir-vm>UAB-Histology-00121</peir-vm> <br />
<br />
{{Template:Histologic}}<br />
<br />
[[Category:Histologic]]</div>Matthew Andersonhttps://peir.path.uab.edu/index.php?title=File:HistologicChapter15Glomerulus.jpg&diff=3237File:HistologicChapter15Glomerulus.jpg2014-07-18T05:41:28Z<p>Matthew Anderson: </p>
<hr />
<div></div>Matthew Andersonhttps://peir.path.uab.edu/index.php?title=Histologic:Chapter_15&diff=3236Histologic:Chapter 152014-07-18T05:39:32Z<p>Matthew Anderson: /* Slide 117, Kidney (Masson) */</p>
<hr />
<div>== Kidney ==<br />
[[File:HistologicChapter15Kidney.jpg|thumb|200px|Kidney]]<br />
A good knowledge of normal kidney histology is essential for the understanding of various diseases of the kidney. <br />
<br />
=== Slide 117, Kidney (Masson) ===<br />
[[File:HistologicChapter15KidneyLabelled.jpg|thumb|200px|Kidney]]<br />
Observe Slide 117, kidney (Masson) with the unaided eye to distinguish the lighter stained medulla from the more peripheral and darker-staining cortex. Now, with low and medium powers of the microscope identify:<br />
<br />
*The thin, fibrous capsule of the kidney. Scan the entire slide to observe that the only prominent connective tissue fibers within the kidney are in association with blood vessels.<br />
<br />
*The cortex containing the renal corpuscles.<br />
<br />
*The medulla in which renal corpuscles are lacking.<br />
<br />
*The larger blood vessels at the corticomedullary junction. These are arcuate arteries and veins.<br />
<br />
Study the cortex of the kidney for details of its organization. On Slide 114, Slide 116, Slide 117, and Slide 118 identify:<br />
<br />
Pars radiata (medullary rays) are columns of straight tubules extending from the cortex into the medulla and from the medulla into the cortex. <br />
<br />
The straight segments of the proximal and distal tubules and the straight collecting tubules are located here.<br />
<br />
Pars convoluta (cortical labyrinths) areas occupy the region between pars radiata.<br />
<br />
Within the pars convoluta can be found renal corpuscles, proximal convoluted tubules (PCT), distal convoluted tubules (DCT), and blood vessels (the interlobular arteries and veins and the afferent and efferent arterioles). A kidney lobule consists of a pars radiata and “half” of each adjoining pars convoluta.<br />
<br />
Learn to distinguish the PCT from the DCT. With the light microscope the straight portion of the proximal tubule is histologically similar to the PCT and the straight portion of the distal tubule is similar to the DCT.<br />
<br />
Proximal convoluted tubule (PCT). The PCT may be up to 14 mm in length. This is more than twice as long as the average DCT, which is about 5 mm long. Thus, one sees more sections through PCT in any given region of the pars convoluta than through DCT.<br />
<br />
*The PCT stains darker than the DCT.<br />
<br />
*The PCT cells are larger and the cytoplasm is more granular than the cells of the DCT. This is due to the large number of mitochondria in the cytoplasm of the PCT cells.<br />
<br />
*The cell boundaries of the PCT are less distinct than the DCT because the membranes of the PCT cells are more highly interdigitated with the membranes of neighboring cells. And the PCT is larger in cross section than the DCT.<br />
<br />
*The apical surface of the PCT exhibits microvilli, about 1.2 μm in length, which form a brush border when observed with the light microscope. This border disintegrates quickly when postmortem changes set in. A brush border is lacking on cells of the DCT although the EM demonstrates the presence of a few microvilli.<br />
<br />
*The cells of the PCT are low columnar to pyramidal; those of the DCT are more cuboidal in shape.<br />
<br />
<peir-vm>UAB-Histology-00117</peir-vm><br />
<br />
==== Slide 114, Kidney ====<br />
<peir-vm>UAB-Histology-00114</peir-vm><br />
==== Slide 116, Kidney ====<br />
<peir-vm>UAB-Histology-00116</peir-vm><br />
<br />
=== Slide 118, Kidney (PASH) ===<br />
<br />
The renal corpuscles on Slide 118, Kidney (PASH) are to be studied in detail.<br />
<br />
First, with low power, become oriented to the section on Slide 118. This is a tangential section through the cortex of the kidney. Thus, renal corpuscles are found throughout the. Note that tubules in the pars radiata are cut in cross section and appear to be grouped into bundles surrounded (or bordered) by pars convoluta. We will study these tubules in detail later.<br />
<br />
On high power study several renal corpuscles on Slide 118. A renal corpuscle ranges from 150 to 250 μm in diameter. It consists of a tuft of capillaries called the glomerulus and a surrounding epithelial capsule called the glomerular capsule (Bowman’s capsule). This latter structure has an outer layer of simple squamous epithelial cells with a basement membrane. The cells and basement membrane form the parietal layer of Bowman’s capsule, which surrounds Bowman’s space or the urinary space. A layer of visceral epithelial cells covers the glomerular basement membrane. The cells of this highly modified epithelial layer are called podocytes because of numerous foot-like processes (pedicels) that they possess. The space between the visceral and parietal layers of Bowman’s capsule is termed Bowman’s space or urinary space within which the glomerular filtrate is collected and passes into the PCT. The parietal epithelial cells are continuous with the neck of the PCT and with the visceral layer at the vascular pole.<br />
<br />
Identify:<br />
<br />
*The simple squamous epithelial cells of the parietal layer.<br />
*The basement membrane on which the cells lie.<br />
*The urinary space.<br />
<br />
The glomerulus is a specialized bed of capillaries connecting an afferent arteriole with an efferent arteriole at the vascular pole of the renal corpuscle. The urinary pole of the renal corpuscle where the glomerular filtrate passes into the PCT usually lies opposite the vascular pole. <br />
<br />
Find, if present, a renal corpuscle sectioned so as to demonstrate both the vascular and urinary poles.<br />
<br />
Study several glomeruli in detail.<br />
<br />
*A glomerulus appears lobulated since the looped capillaries from a major capillary branch are grouped together. About 5-8 major capillary trunks (lobules) are formed in each glomerulus. Up to 50 capillary loops may be present.<br />
<br />
*Anastomoses occur between capillaries of the same lobule and of different lobules.<br />
<br />
*The afferent arteriole supplying blood to the glomerulus is usually larger than the efferent arteriole.<br />
<br />
*The endothelial cells lining the capillary lumen are fairly large, attenuated, flattened cells with nuclei bulging into the lumen. The fenestrated endothelium has numerous pores that vary from 50 to 100 nm in diameters. These endothelial cells are only partially surrounded by a basement membrane that is about 300 nm thick in adults. The capillaries of each lobule wind around a common axis that appears as a cellular stalk of mesangial cells and mesangial matrix. Basement membrane is lacking between the capillary endothelium and the stalk of the capillary lobule occupied by the mesangial cells and mesangial matrix. Hence, instead of surrounding the entire lumen of a capillary loop, the basement membrane is reflected onto adjacent capillary loops. The mesangial cells are located inside of the basement membrane of the capillary lobule, and they are in direct contact with the endothelial cells where basement membrane material is lacking.<br />
<br />
*Identify the nuclei of endothelial cells, mesangial cells lying in mesangial matrix, and the nuclei of podocytes.<br />
<br />
On Slide 118 select, an “open appearing” capillary loop cut in cross section, lying towards the outer edge of a glomerulus and within which a nucleus can be seen bulging into the lumen. This is the nucleus of an endothelial cell. The nuclei tend to lie on the wall of the capillary loop nearest the central axis.<br />
<br />
Find a slightly darker staining nucleus, about the same size as the endothelial nucleus, embedded in the denser, darkly stained PAS-positive material. This is a mesangial cell nucleus and the PAS-positive staining material is mesangial matrix. The mesangial cell lies to the inner side of the basement membrane. Electron micrographs show that the mesangial cells are in direct contact with the endothelial cells. The mesangial matrix produced by the mesangial cells is a basement membrane-like material that increases with age and in certain disease states such as diabetic nephropathy and glomerulonephritis.<br />
<br />
Identify slightly larger, slightly paler staining nuclei lying outside the basement membrane. They are podocyte nuclei. The interdigitated cytoplasmic extensions of the podocytes, which line the outside of the basement membrane, can be seen only with the electron microscope.<br />
<br />
Filtration Barrier. In order for substances in the blood to reach the urinary space as glomerular filtrate they must pass through the filtration barrier. This important barrier includes the endothelium of the capillary, basal lamina and slit pores between adjacent pedicles (foot processes) of the podocytes. The slit pores are about 250 nm in diameter and they are bridges by a thin diaphragm called the filtration slit membrane.<br />
<br />
Identify on Slide 117 the endothelial cells of the glomerular capillary, the mesangial cells and mesangial matrix, and the podocytes. On this section stained with Masson’s stain the basement membrane of the glomerulus appears as a very thin blue line. The mesangial matrix is readily identified as the purplish-staining material between capillaries.<br />
<br />
Juxtaglomerular apparatus. On Slide 118 attempt to find a juxtaglomerular apparatus where the distal tubule comes into close association with the afferent glomerular arteriole at the vascular pole of each Bowman’s capsule. This composite structure consists of the macula densa of the distal tubule, lacis cells (extraglomerular mesangial cells) and juxtaglomerular cells (JG cells). The latter cells are modified smooth muscle cells in the tunica media of the afferent arteriole. These secretory, epithelioid cells replace the smooth muscle cells of the media only in the localized region of the juxtaglomerular apparatus. The JG cells are separated from the cells forming the macula densa only by a basal lamina. The JG cells are important since they secrete renin.<br />
<br />
The macula densa is identified as being an area of tall, slender cells on the side of the distal tubule adjacent to the afferent arteriole. Since the cells are narrow, the nuclei appear closely packed together, and with the light microscope the area appears denser than surrounding areas (macula densa = “dense spot”). The function of these cells is to monitor sodium in the distal tubule and “pass” this information to the JG cells to alter their secretory activity.<br />
<br />
The lacis cells are small agranular cells lying in a triangular area bounded by the afferent and efferent arterioles and the macula densa. The lacis cells are embedded in a dense network of basement membranes. They are continuous with the mesangium of the capillary stalk. The specific function of lacis cells is not well understood, although it has been associated with the secretion of erythropoietin.<br />
<br />
Study the tubules in the medulla of the kidney on Slides 114, 116, and 117. A straight collecting tubule lying in the pars radiata of the cortex receives 7 to 10 arched collecting tubules as it passes into the outer zone of the medulla. Continuing into the inner zone of the medulla the straight collecting tubules unite with other similar tubules to form large papillary ducts. These open into the minor calyces at the area cribrosa of a renal papilla. Papillary ducts are not found in the outer zone of the medulla. The straight collecting tubules have a diameter of about 40μm as compared with a diameter of 200 μm for the papillary ducts.<br />
<br />
On Slide 117 identify straight collecting tubules in the medulla. They exhibit a lining of large pale staining, simple columnar cells with well-defined cell boundaries. <br />
<br />
Identify the smallest tubules cut in cross section in the medulla. These are the thin segments of the loops of Henle. Only the juxtamedullary nephrons have thin segments extending deep into the medulla. The thin segments of Henle’s loop are easily confused with capillaries or venules. They are composed of a single layer of flattened epithelial cells having round to ovoid nuclei that tend to bulge into the lumen. The cells sit on a basement membrane. The overall diameter of the segment is about 15μm, and cross sections of them usually contain 3 to 5 nuclei. Remember that the loops of Henle are made up of both thick and thin segments. The thick segments form descending and ascending limbs. An abrupt change occurs in the epithelium where the thick segments meet the thin segments.<br />
<br />
Return to Slide 118 and identify the collecting ducts in the pars radiata. They have many nuclei in cross section and have distinctly visible cell boundaries. In the pars convoluta the proximal convoluted tubules are easily identified by the PAS-positive staining of their brush border. The straight portion of the proximal tubule in the pars radiata appears similar. The straight portions of the distal tubules (thick ascending segment of Henle’s loop) located in the pars radiata appear to have undergone more postmortem change than other parts of the tubule. The straight distal tubules exhibit cells that are somewhat disrupted and pulled free of the basement membrane. Many cells appear to be “floating” within the lumen of the tubule. Identify the straight proximal and distal tubule.<br />
<br />
Blood supply<br />
<br />
The circulation of blood through the kidney is rather complex and should be studied in your textbook before attempting to understand it from slides. Only a few aspects of the overall circulation can be seen on any one microscopic slide.<br />
<br />
On Slide 117 identify the arcuate arteries and the arcuate veins at the corticomedullary junction. The arteries are continuations (branches) of the larger interlobar arteries.<br />
<br />
Each arcuate artery gives off several interlobular arteries that pass perpendicularly through a pars convoluta to the surface of the kidney. Identify interlobular arteries on Slide 117; they are very small arteries or arterioles. Thin-walled interlobular veins (mostly venules) are seen adjacent to some of the interlobular arteries. The arteries and veins pass more or less through the middle of a pars convoluta. The area between two interlobular arteries and veins is a kidney lobule. On Slide 118 identify interlobular arteries cut in cross section and lying within a pars convoluta. A number of afferent glomerular arterioles are given off by the interlobular artery before it terminates as a capillary bed beneath the capsule of the kidney.<br />
<br />
On Slide 117 identify the erythrocytes in capillaries that are interspersed between the convoluted tubules. In the outer cortex, the capillaries originate from the efferent arterioles to form a peritubular plexus, which in the living condition appears to bathe the tubules in blood. The capillaries drain into cortical venules that empty into interlobular veins that accompany the interlobular arteries.<br />
<br />
The efferent arterioles leaving glomeruli near the medulla are relatively larger than the efferent arterioles in the outer cortex. They extend into the medulla as the arteriolae rectae spuriae. Pursuing a straight course in the medulla, these vessels give rise to capillary nets that extend deeply into the papillae. Veins called venae rectae return the blood to the arcuate veins. Collectively the blood supply of the medulla in which these thin-walled vessels make hairpin loops is called the vasa rectae.<br />
<br />
Interstitial connective tissue. The connective tissue of the kidney is not nearly as extensive as in other organs. Most of the prominent connective tissue is in association with blood vessels, lymphatics and nerves. The more delicate and looser connective tissue spreads through the renal parenchyma. It is more abundant in the medulla than in the cortex. This poorly developed interstitial tissue consists principally of reticular and collagenous fibers with associated fibroblasts and macrophages. Observe on Slide 117 (Masson) that the large blood vessels are invested with the densest connective tissue, the adventitia. Very delicate collagen fibers can be seen surrounding tubules in the medulla. They appear as a pale blue network. Reticular fibers also form a diffuse network around the tubules. Compare the amount of interstitial connective tissue in the medulla with the amount present around the convoluted tubules of the cortex. The interstitial diseases of the kidney form from or directly affect the interstitial tissue. In severe systemic infections, non- specific inflammatory changes can occur in the interstitium.<br />
<br />
The sinus of the kidney is the concave indentation or potential cavity on the hilus side of the kidney. It lies adjacent to kidney cortex of the renal columns and to medulla. It contains loose connective tissue and fat. In it are embedded branches of the renal artery and vein, lymphatics, nerves, minor calyces, major calyces and the renal pelvis.<br />
<br />
<peir-vm>UAB-Histology-00118</peir-vm><br />
<br />
=== Slide 92, Kidney, Ureter, Vessels ===<br />
<br />
Study Slide 92. Section through the sinus of the kidney showing several blood vessels, nerves, and a section of ureter, all embedded in loose connective and adipose tissue (H&E).<br />
<br />
<peir-vm>UAB-Histology-00092</peir-vm><br />
<br />
== Ureter and Urinary Bladder ==<br />
<br />
=== Ureter ===<br />
<br />
The ureters conduct urine from the kidneys to the bladder. They are about 12 inches long, course behind the peritoneum, and consist of three layers (a mucosa, a muscularis and a fibrosa).<br />
<br />
==== Slide 120, Ureter (Masson) ====<br />
<br />
Study Slide 120, Ureter (Masson), which is a cross section through the lower one-third of the ureter. At low and medium power observe:<br />
<br />
The mucosa consisting of transitional epithelium and a lamina propria. Note the stellate-shaped lumen formed by the folds of the lamina propria, the density of the lamina propria, and the thickness of the epithelium.<br />
<br />
The muscularis has three layers of smooth muscle since this section was taken from the lower one-third of the ureter. The upper two-thirds of the ureter has only two layers of smooth muscle in the muscularis. Identify, here, an inner longitudinal layer with fibers cut in cross section, the middle circular layer and an outer longitudinal layer. It is this outer layer that is the “extra layer” of the lower ureter. Note how the muscle bundles are separated by abundant connective tissue.<br />
<br />
Identify the fibrosa lying outside the muscularis. This loose connective tissue layer binds the ureter to adjoining structures. Observe the blood vessels running through the fibrosa, which also contains nerves, lymphatics and fat cells.<br />
<br />
<peir-vm>UAB-Histology-00120</peir-vm><br />
<br />
==== Slide 119, Ureter (H&E) ====<br />
<br />
Examine Slide 119, Ureter (H&E) under low and medium power for most of the features just studied on Slide 120. In addition, note that:<br />
<br />
*With H&E, the muscle layers do not contrast well with the connective tissue fibers. Hence, it is difficult to distinguish that the middle portion of the ureter from which this section was taken has only two muscle layers instead of three. These are an inner longitudinal layer and an outer circular layer. <br />
<br />
*Note the abundance of adipose tissue in the fibrosa. Identify the small arteries and veins occurring in this layer.<br />
<br />
*Study the mucosa of slide 119 at high power.<br />
<br />
It consists of a transitional epithelium of 5 to 6 cell layers thick. The surface cells of transitional epithelium, called cap cells, are larger and stain more darkly than the underlying cells. In some areas, the surface cells are stretched so as to appear almost squamous. The epithelium rests on a basement membrane, but the membrane is so thin that it is only identified with the electron microscope.<br />
<br />
The lamina propria is a rather dense-appearing connective tissue layer between the epithelium and the muscularis. It contains collagenous fibers, elastic fibers and connective tissue cells. In the Masson-stained ureter, Slide 120, venules and capillaries are more readily seen within the lamina propria than they are in Slide 119.<br />
<br />
Study the muscularis on Slide 119. This section is from the middle ureter that has only two layers of smooth muscle, an inner longitudinal and an outer circular layer. Contraction of the smooth muscle aids in passing the urine through the ureters.<br />
<br />
<peir-vm>UAB-Histology-00119</peir-vm><br />
<br />
=== Urinary Bladder ===<br />
<br />
The urinary bladder consists of a mucosa, a muscularis and an adventitia that is either a fibrosa (where it blends with the connective tissue of surrounding structures) or a serosa (found only on the superior surface where the bladder is covered with peritoneum).<br />
<br />
==== Slide 121, Urinary Bladder (H&E) ====<br />
<br />
Scan the slide with low and medium powers to identify the three major layers. <br />
<br />
Study the mucosa for details. A lining of transitional epithelium and underlying lamina propria form the mucosa. The empty bladder usually has a folded mucosa, the distended bladder a smooth one. Examine the epithelium in different regions of this section. In the relaxed bladder, as seen here, the epithelium is six or more cell layers thick; whereas in the distended bladder the epithelium is so stretched it appears to be only two or three cell layers thick. Recall that the epithelium is a special type of stratified epithelium that undergoes “transitional changes” to allow for the filling and emptying of the bladder.<br />
<br />
Examine the surface cells. Observe in some regions their dome-shaped apices, and how they appear to “cap” the smaller underlying cells. These cap cells are occasionally binucleated. They are stretched into a “squamous” layer in the distended bladder. The cells immediately beneath the surface cells are pear-shaped or flask-shaped and their apices fit into facet-like indentations on the underside of the surface cells. The basal layer cells undergo mitosis to replenish the surface cells sloughed off into the lumen of the urinary bladder.<br />
<br />
The luminal plasma membrane of the surface cells is thicker than most plasma membranes. This specialization, in conjunction with the superficial layer of cytoplasm containing numerous tonofilaments (microfilaments), serves to protect the epithelium from the hypertonicity of the urine, prevents urine resorption and acts as a barrier to the loss of water from the cells into the hypertonic urine.<br />
<br />
The connective tissue underlying the transitional epithelium is the lamina propria. It is mostly collagenous fibers in which some elastic networks occur. Lymphocytes wander through the lamina propria and an occasional solitary lymphatic nodule can be present (but it is unlikely that you will see one on our slides). Observe that the deeper region of the lamina propria gives rise to an extensive capillary bed beneath the epithelium.<br />
<br />
The muscularis of the bladder has three layers of smooth muscle indistinctly arranged into an inner longitudinal layer, a middle circular layer, and an outer longitudinal layer. The middle circular layer is the thickest but this may be difficult to identify on your slides, since the different muscle bundles tend to interlace and anastomose. Observe the abundant connective tissue that separates bundles of muscle. The muscularis has an abundant blood supply with an extensive capillary network.<br />
<br />
Adventitia. This section of bladder is covered by a serosa consisting of a surface mesothelium. <br />
<br />
<peir-vm>UAB-Histology-00121</peir-vm> <br />
<br />
{{Template:Histologic}}<br />
<br />
[[Category:Histologic]]</div>Matthew Andersonhttps://peir.path.uab.edu/index.php?title=File:HistologicChapter15KidneyLabelled.jpg&diff=3235File:HistologicChapter15KidneyLabelled.jpg2014-07-18T05:39:15Z<p>Matthew Anderson: </p>
<hr />
<div></div>Matthew Andersonhttps://peir.path.uab.edu/index.php?title=Histologic:Chapter_15&diff=3234Histologic:Chapter 152014-07-18T05:37:46Z<p>Matthew Anderson: /* Kidney */</p>
<hr />
<div>== Kidney ==<br />
[[File:HistologicChapter15Kidney.jpg|thumb|200px|Kidney]]<br />
A good knowledge of normal kidney histology is essential for the understanding of various diseases of the kidney. <br />
<br />
=== Slide 117, Kidney (Masson) ===<br />
<br />
Observe Slide 117, kidney (Masson) with the unaided eye to distinguish the lighter stained medulla from the more peripheral and darker-staining cortex. Now, with low and medium powers of the microscope identify:<br />
<br />
*The thin, fibrous capsule of the kidney. Scan the entire slide to observe that the only prominent connective tissue fibers within the kidney are in association with blood vessels.<br />
<br />
*The cortex containing the renal corpuscles.<br />
<br />
*The medulla in which renal corpuscles are lacking.<br />
<br />
*The larger blood vessels at the corticomedullary junction. These are arcuate arteries and veins.<br />
<br />
Study the cortex of the kidney for details of its organization. On Slide 114, Slide 116, Slide 117, and Slide 118 identify:<br />
<br />
Pars radiata (medullary rays) are columns of straight tubules extending from the cortex into the medulla and from the medulla into the cortex. <br />
<br />
The straight segments of the proximal and distal tubules and the straight collecting tubules are located here.<br />
<br />
Pars convoluta (cortical labyrinths) areas occupy the region between pars radiata.<br />
<br />
Within the pars convoluta can be found renal corpuscles, proximal convoluted tubules (PCT), distal convoluted tubules (DCT), and blood vessels (the interlobular arteries and veins and the afferent and efferent arterioles). A kidney lobule consists of a pars radiata and “half” of each adjoining pars convoluta.<br />
<br />
Learn to distinguish the PCT from the DCT. With the light microscope the straight portion of the proximal tubule is histologically similar to the PCT and the straight portion of the distal tubule is similar to the DCT.<br />
<br />
Proximal convoluted tubule (PCT). The PCT may be up to 14 mm in length. This is more than twice as long as the average DCT, which is about 5 mm long. Thus, one sees more sections through PCT in any given region of the pars convoluta than through DCT.<br />
<br />
*The PCT stains darker than the DCT.<br />
<br />
*The PCT cells are larger and the cytoplasm is more granular than the cells of the DCT. This is due to the large number of mitochondria in the cytoplasm of the PCT cells.<br />
<br />
*The cell boundaries of the PCT are less distinct than the DCT because the membranes of the PCT cells are more highly interdigitated with the membranes of neighboring cells. And the PCT is larger in cross section than the DCT.<br />
<br />
*The apical surface of the PCT exhibits microvilli, about 1.2 μm in length, which form a brush border when observed with the light microscope. This border disintegrates quickly when postmortem changes set in. A brush border is lacking on cells of the DCT although the EM demonstrates the presence of a few microvilli.<br />
<br />
*The cells of the PCT are low columnar to pyramidal; those of the DCT are more cuboidal in shape.<br />
<br />
<peir-vm>UAB-Histology-00117</peir-vm><br />
<br />
==== Slide 114, Kidney ====<br />
<peir-vm>UAB-Histology-00114</peir-vm><br />
==== Slide 116, Kidney ====<br />
<peir-vm>UAB-Histology-00116</peir-vm><br />
<br />
=== Slide 118, Kidney (PASH) ===<br />
<br />
The renal corpuscles on Slide 118, Kidney (PASH) are to be studied in detail.<br />
<br />
First, with low power, become oriented to the section on Slide 118. This is a tangential section through the cortex of the kidney. Thus, renal corpuscles are found throughout the. Note that tubules in the pars radiata are cut in cross section and appear to be grouped into bundles surrounded (or bordered) by pars convoluta. We will study these tubules in detail later.<br />
<br />
On high power study several renal corpuscles on Slide 118. A renal corpuscle ranges from 150 to 250 μm in diameter. It consists of a tuft of capillaries called the glomerulus and a surrounding epithelial capsule called the glomerular capsule (Bowman’s capsule). This latter structure has an outer layer of simple squamous epithelial cells with a basement membrane. The cells and basement membrane form the parietal layer of Bowman’s capsule, which surrounds Bowman’s space or the urinary space. A layer of visceral epithelial cells covers the glomerular basement membrane. The cells of this highly modified epithelial layer are called podocytes because of numerous foot-like processes (pedicels) that they possess. The space between the visceral and parietal layers of Bowman’s capsule is termed Bowman’s space or urinary space within which the glomerular filtrate is collected and passes into the PCT. The parietal epithelial cells are continuous with the neck of the PCT and with the visceral layer at the vascular pole.<br />
<br />
Identify:<br />
<br />
*The simple squamous epithelial cells of the parietal layer.<br />
*The basement membrane on which the cells lie.<br />
*The urinary space.<br />
<br />
The glomerulus is a specialized bed of capillaries connecting an afferent arteriole with an efferent arteriole at the vascular pole of the renal corpuscle. The urinary pole of the renal corpuscle where the glomerular filtrate passes into the PCT usually lies opposite the vascular pole. <br />
<br />
Find, if present, a renal corpuscle sectioned so as to demonstrate both the vascular and urinary poles.<br />
<br />
Study several glomeruli in detail.<br />
<br />
*A glomerulus appears lobulated since the looped capillaries from a major capillary branch are grouped together. About 5-8 major capillary trunks (lobules) are formed in each glomerulus. Up to 50 capillary loops may be present.<br />
<br />
*Anastomoses occur between capillaries of the same lobule and of different lobules.<br />
<br />
*The afferent arteriole supplying blood to the glomerulus is usually larger than the efferent arteriole.<br />
<br />
*The endothelial cells lining the capillary lumen are fairly large, attenuated, flattened cells with nuclei bulging into the lumen. The fenestrated endothelium has numerous pores that vary from 50 to 100 nm in diameters. These endothelial cells are only partially surrounded by a basement membrane that is about 300 nm thick in adults. The capillaries of each lobule wind around a common axis that appears as a cellular stalk of mesangial cells and mesangial matrix. Basement membrane is lacking between the capillary endothelium and the stalk of the capillary lobule occupied by the mesangial cells and mesangial matrix. Hence, instead of surrounding the entire lumen of a capillary loop, the basement membrane is reflected onto adjacent capillary loops. The mesangial cells are located inside of the basement membrane of the capillary lobule, and they are in direct contact with the endothelial cells where basement membrane material is lacking.<br />
<br />
*Identify the nuclei of endothelial cells, mesangial cells lying in mesangial matrix, and the nuclei of podocytes.<br />
<br />
On Slide 118 select, an “open appearing” capillary loop cut in cross section, lying towards the outer edge of a glomerulus and within which a nucleus can be seen bulging into the lumen. This is the nucleus of an endothelial cell. The nuclei tend to lie on the wall of the capillary loop nearest the central axis.<br />
<br />
Find a slightly darker staining nucleus, about the same size as the endothelial nucleus, embedded in the denser, darkly stained PAS-positive material. This is a mesangial cell nucleus and the PAS-positive staining material is mesangial matrix. The mesangial cell lies to the inner side of the basement membrane. Electron micrographs show that the mesangial cells are in direct contact with the endothelial cells. The mesangial matrix produced by the mesangial cells is a basement membrane-like material that increases with age and in certain disease states such as diabetic nephropathy and glomerulonephritis.<br />
<br />
Identify slightly larger, slightly paler staining nuclei lying outside the basement membrane. They are podocyte nuclei. The interdigitated cytoplasmic extensions of the podocytes, which line the outside of the basement membrane, can be seen only with the electron microscope.<br />
<br />
Filtration Barrier. In order for substances in the blood to reach the urinary space as glomerular filtrate they must pass through the filtration barrier. This important barrier includes the endothelium of the capillary, basal lamina and slit pores between adjacent pedicles (foot processes) of the podocytes. The slit pores are about 250 nm in diameter and they are bridges by a thin diaphragm called the filtration slit membrane.<br />
<br />
Identify on Slide 117 the endothelial cells of the glomerular capillary, the mesangial cells and mesangial matrix, and the podocytes. On this section stained with Masson’s stain the basement membrane of the glomerulus appears as a very thin blue line. The mesangial matrix is readily identified as the purplish-staining material between capillaries.<br />
<br />
Juxtaglomerular apparatus. On Slide 118 attempt to find a juxtaglomerular apparatus where the distal tubule comes into close association with the afferent glomerular arteriole at the vascular pole of each Bowman’s capsule. This composite structure consists of the macula densa of the distal tubule, lacis cells (extraglomerular mesangial cells) and juxtaglomerular cells (JG cells). The latter cells are modified smooth muscle cells in the tunica media of the afferent arteriole. These secretory, epithelioid cells replace the smooth muscle cells of the media only in the localized region of the juxtaglomerular apparatus. The JG cells are separated from the cells forming the macula densa only by a basal lamina. The JG cells are important since they secrete renin.<br />
<br />
The macula densa is identified as being an area of tall, slender cells on the side of the distal tubule adjacent to the afferent arteriole. Since the cells are narrow, the nuclei appear closely packed together, and with the light microscope the area appears denser than surrounding areas (macula densa = “dense spot”). The function of these cells is to monitor sodium in the distal tubule and “pass” this information to the JG cells to alter their secretory activity.<br />
<br />
The lacis cells are small agranular cells lying in a triangular area bounded by the afferent and efferent arterioles and the macula densa. The lacis cells are embedded in a dense network of basement membranes. They are continuous with the mesangium of the capillary stalk. The specific function of lacis cells is not well understood, although it has been associated with the secretion of erythropoietin.<br />
<br />
Study the tubules in the medulla of the kidney on Slides 114, 116, and 117. A straight collecting tubule lying in the pars radiata of the cortex receives 7 to 10 arched collecting tubules as it passes into the outer zone of the medulla. Continuing into the inner zone of the medulla the straight collecting tubules unite with other similar tubules to form large papillary ducts. These open into the minor calyces at the area cribrosa of a renal papilla. Papillary ducts are not found in the outer zone of the medulla. The straight collecting tubules have a diameter of about 40μm as compared with a diameter of 200 μm for the papillary ducts.<br />
<br />
On Slide 117 identify straight collecting tubules in the medulla. They exhibit a lining of large pale staining, simple columnar cells with well-defined cell boundaries. <br />
<br />
Identify the smallest tubules cut in cross section in the medulla. These are the thin segments of the loops of Henle. Only the juxtamedullary nephrons have thin segments extending deep into the medulla. The thin segments of Henle’s loop are easily confused with capillaries or venules. They are composed of a single layer of flattened epithelial cells having round to ovoid nuclei that tend to bulge into the lumen. The cells sit on a basement membrane. The overall diameter of the segment is about 15μm, and cross sections of them usually contain 3 to 5 nuclei. Remember that the loops of Henle are made up of both thick and thin segments. The thick segments form descending and ascending limbs. An abrupt change occurs in the epithelium where the thick segments meet the thin segments.<br />
<br />
Return to Slide 118 and identify the collecting ducts in the pars radiata. They have many nuclei in cross section and have distinctly visible cell boundaries. In the pars convoluta the proximal convoluted tubules are easily identified by the PAS-positive staining of their brush border. The straight portion of the proximal tubule in the pars radiata appears similar. The straight portions of the distal tubules (thick ascending segment of Henle’s loop) located in the pars radiata appear to have undergone more postmortem change than other parts of the tubule. The straight distal tubules exhibit cells that are somewhat disrupted and pulled free of the basement membrane. Many cells appear to be “floating” within the lumen of the tubule. Identify the straight proximal and distal tubule.<br />
<br />
Blood supply<br />
<br />
The circulation of blood through the kidney is rather complex and should be studied in your textbook before attempting to understand it from slides. Only a few aspects of the overall circulation can be seen on any one microscopic slide.<br />
<br />
On Slide 117 identify the arcuate arteries and the arcuate veins at the corticomedullary junction. The arteries are continuations (branches) of the larger interlobar arteries.<br />
<br />
Each arcuate artery gives off several interlobular arteries that pass perpendicularly through a pars convoluta to the surface of the kidney. Identify interlobular arteries on Slide 117; they are very small arteries or arterioles. Thin-walled interlobular veins (mostly venules) are seen adjacent to some of the interlobular arteries. The arteries and veins pass more or less through the middle of a pars convoluta. The area between two interlobular arteries and veins is a kidney lobule. On Slide 118 identify interlobular arteries cut in cross section and lying within a pars convoluta. A number of afferent glomerular arterioles are given off by the interlobular artery before it terminates as a capillary bed beneath the capsule of the kidney.<br />
<br />
On Slide 117 identify the erythrocytes in capillaries that are interspersed between the convoluted tubules. In the outer cortex, the capillaries originate from the efferent arterioles to form a peritubular plexus, which in the living condition appears to bathe the tubules in blood. The capillaries drain into cortical venules that empty into interlobular veins that accompany the interlobular arteries.<br />
<br />
The efferent arterioles leaving glomeruli near the medulla are relatively larger than the efferent arterioles in the outer cortex. They extend into the medulla as the arteriolae rectae spuriae. Pursuing a straight course in the medulla, these vessels give rise to capillary nets that extend deeply into the papillae. Veins called venae rectae return the blood to the arcuate veins. Collectively the blood supply of the medulla in which these thin-walled vessels make hairpin loops is called the vasa rectae.<br />
<br />
Interstitial connective tissue. The connective tissue of the kidney is not nearly as extensive as in other organs. Most of the prominent connective tissue is in association with blood vessels, lymphatics and nerves. The more delicate and looser connective tissue spreads through the renal parenchyma. It is more abundant in the medulla than in the cortex. This poorly developed interstitial tissue consists principally of reticular and collagenous fibers with associated fibroblasts and macrophages. Observe on Slide 117 (Masson) that the large blood vessels are invested with the densest connective tissue, the adventitia. Very delicate collagen fibers can be seen surrounding tubules in the medulla. They appear as a pale blue network. Reticular fibers also form a diffuse network around the tubules. Compare the amount of interstitial connective tissue in the medulla with the amount present around the convoluted tubules of the cortex. The interstitial diseases of the kidney form from or directly affect the interstitial tissue. In severe systemic infections, non- specific inflammatory changes can occur in the interstitium.<br />
<br />
The sinus of the kidney is the concave indentation or potential cavity on the hilus side of the kidney. It lies adjacent to kidney cortex of the renal columns and to medulla. It contains loose connective tissue and fat. In it are embedded branches of the renal artery and vein, lymphatics, nerves, minor calyces, major calyces and the renal pelvis.<br />
<br />
<peir-vm>UAB-Histology-00118</peir-vm><br />
<br />
=== Slide 92, Kidney, Ureter, Vessels ===<br />
<br />
Study Slide 92. Section through the sinus of the kidney showing several blood vessels, nerves, and a section of ureter, all embedded in loose connective and adipose tissue (H&E).<br />
<br />
<peir-vm>UAB-Histology-00092</peir-vm><br />
<br />
== Ureter and Urinary Bladder ==<br />
<br />
=== Ureter ===<br />
<br />
The ureters conduct urine from the kidneys to the bladder. They are about 12 inches long, course behind the peritoneum, and consist of three layers (a mucosa, a muscularis and a fibrosa).<br />
<br />
==== Slide 120, Ureter (Masson) ====<br />
<br />
Study Slide 120, Ureter (Masson), which is a cross section through the lower one-third of the ureter. At low and medium power observe:<br />
<br />
The mucosa consisting of transitional epithelium and a lamina propria. Note the stellate-shaped lumen formed by the folds of the lamina propria, the density of the lamina propria, and the thickness of the epithelium.<br />
<br />
The muscularis has three layers of smooth muscle since this section was taken from the lower one-third of the ureter. The upper two-thirds of the ureter has only two layers of smooth muscle in the muscularis. Identify, here, an inner longitudinal layer with fibers cut in cross section, the middle circular layer and an outer longitudinal layer. It is this outer layer that is the “extra layer” of the lower ureter. Note how the muscle bundles are separated by abundant connective tissue.<br />
<br />
Identify the fibrosa lying outside the muscularis. This loose connective tissue layer binds the ureter to adjoining structures. Observe the blood vessels running through the fibrosa, which also contains nerves, lymphatics and fat cells.<br />
<br />
<peir-vm>UAB-Histology-00120</peir-vm><br />
<br />
==== Slide 119, Ureter (H&E) ====<br />
<br />
Examine Slide 119, Ureter (H&E) under low and medium power for most of the features just studied on Slide 120. In addition, note that:<br />
<br />
*With H&E, the muscle layers do not contrast well with the connective tissue fibers. Hence, it is difficult to distinguish that the middle portion of the ureter from which this section was taken has only two muscle layers instead of three. These are an inner longitudinal layer and an outer circular layer. <br />
<br />
*Note the abundance of adipose tissue in the fibrosa. Identify the small arteries and veins occurring in this layer.<br />
<br />
*Study the mucosa of slide 119 at high power.<br />
<br />
It consists of a transitional epithelium of 5 to 6 cell layers thick. The surface cells of transitional epithelium, called cap cells, are larger and stain more darkly than the underlying cells. In some areas, the surface cells are stretched so as to appear almost squamous. The epithelium rests on a basement membrane, but the membrane is so thin that it is only identified with the electron microscope.<br />
<br />
The lamina propria is a rather dense-appearing connective tissue layer between the epithelium and the muscularis. It contains collagenous fibers, elastic fibers and connective tissue cells. In the Masson-stained ureter, Slide 120, venules and capillaries are more readily seen within the lamina propria than they are in Slide 119.<br />
<br />
Study the muscularis on Slide 119. This section is from the middle ureter that has only two layers of smooth muscle, an inner longitudinal and an outer circular layer. Contraction of the smooth muscle aids in passing the urine through the ureters.<br />
<br />
<peir-vm>UAB-Histology-00119</peir-vm><br />
<br />
=== Urinary Bladder ===<br />
<br />
The urinary bladder consists of a mucosa, a muscularis and an adventitia that is either a fibrosa (where it blends with the connective tissue of surrounding structures) or a serosa (found only on the superior surface where the bladder is covered with peritoneum).<br />
<br />
==== Slide 121, Urinary Bladder (H&E) ====<br />
<br />
Scan the slide with low and medium powers to identify the three major layers. <br />
<br />
Study the mucosa for details. A lining of transitional epithelium and underlying lamina propria form the mucosa. The empty bladder usually has a folded mucosa, the distended bladder a smooth one. Examine the epithelium in different regions of this section. In the relaxed bladder, as seen here, the epithelium is six or more cell layers thick; whereas in the distended bladder the epithelium is so stretched it appears to be only two or three cell layers thick. Recall that the epithelium is a special type of stratified epithelium that undergoes “transitional changes” to allow for the filling and emptying of the bladder.<br />
<br />
Examine the surface cells. Observe in some regions their dome-shaped apices, and how they appear to “cap” the smaller underlying cells. These cap cells are occasionally binucleated. They are stretched into a “squamous” layer in the distended bladder. The cells immediately beneath the surface cells are pear-shaped or flask-shaped and their apices fit into facet-like indentations on the underside of the surface cells. The basal layer cells undergo mitosis to replenish the surface cells sloughed off into the lumen of the urinary bladder.<br />
<br />
The luminal plasma membrane of the surface cells is thicker than most plasma membranes. This specialization, in conjunction with the superficial layer of cytoplasm containing numerous tonofilaments (microfilaments), serves to protect the epithelium from the hypertonicity of the urine, prevents urine resorption and acts as a barrier to the loss of water from the cells into the hypertonic urine.<br />
<br />
The connective tissue underlying the transitional epithelium is the lamina propria. It is mostly collagenous fibers in which some elastic networks occur. Lymphocytes wander through the lamina propria and an occasional solitary lymphatic nodule can be present (but it is unlikely that you will see one on our slides). Observe that the deeper region of the lamina propria gives rise to an extensive capillary bed beneath the epithelium.<br />
<br />
The muscularis of the bladder has three layers of smooth muscle indistinctly arranged into an inner longitudinal layer, a middle circular layer, and an outer longitudinal layer. The middle circular layer is the thickest but this may be difficult to identify on your slides, since the different muscle bundles tend to interlace and anastomose. Observe the abundant connective tissue that separates bundles of muscle. The muscularis has an abundant blood supply with an extensive capillary network.<br />
<br />
Adventitia. This section of bladder is covered by a serosa consisting of a surface mesothelium. <br />
<br />
<peir-vm>UAB-Histology-00121</peir-vm> <br />
<br />
{{Template:Histologic}}<br />
<br />
[[Category:Histologic]]</div>Matthew Andersonhttps://peir.path.uab.edu/index.php?title=File:HistologicChapter15Kidney.jpg&diff=3233File:HistologicChapter15Kidney.jpg2014-07-18T05:37:30Z<p>Matthew Anderson: </p>
<hr />
<div></div>Matthew Andersonhttps://peir.path.uab.edu/index.php?title=Template:Histologic&diff=3232Template:Histologic2014-07-18T05:36:03Z<p>Matthew Anderson: </p>
<hr />
<div>{{Navbox<br />
|name = Histologic<br />
|title = [[Histologic]]<br />
|bodyclass = hlist<br />
[[Histologic]]<br />
|group1 = [[Histologic:Chapter 1|Chapter 1]]<br />
|list1 =<br />
* [[Histologic:Chapter 1#Introduction|Introduction]]<br />
* [[Histologic:Chapter 1#Overview_of_Tissue_Preparation_and_Staining_for_Microscopy|Overview of Tissue Preparation and Staining for Microscopy]]<br />
* [[Histologic:Chapter 1#Using_Histologic|Using Histologic]]<br />
|group2 = [[Histologic:Chapter 2|Chapter 2]]<br />
|list2 =<br />
* [[Histologic:Chapter 2#Cells,_Organelles,_and_Inclusions|Cells, Organelles, and Inclusions]]<br />
* [[Histologic:Chapter 2#Mitosis|Mitosis]]<br />
|group3 = [[Histologic:Chapter 3|Chapter 3]]<br />
|list3 =<br />
* [[Histologic:Chapter 3#Introduction|Introduction]]<br />
* [[Histologic:Chapter 3#Simple_Epithelium|Simple Epithelium]]<br />
* [[Histologic:Chapter 3#Stratified_Epithelium|Stratified Epithelium]]<br />
|group4 = [[Histologic:Chapter 4|Chapter 4]]<br />
|list4 =<br />
* [[Histologic:Chapter 4#Introduction|Introduction]]<br />
* [[Histologic:Chapter 4#Loose_Connective_Tissue|Loose Connective Tissue]]<br />
* [[Histologic:Chapter 4#Dense_Connective_Tissue|Dense Connective Tissue]]<br />
* [[Histologic:Chapter 4#Adipose_Tissue|Adipose Tissue]]<br />
|group5 = [[Histologic:Chapter 5|Chapter 5]]<br />
|list5 =<br />
* [[Histologic:Chapter 5#Introduction|Introduction]]<br />
* [[Histologic:Chapter 5#Smooth_Muscle|Smooth Muscle]]<br />
* [[Histologic:Chapter 5#Skeletal_Muscle|Skeletal Muscle]]<br />
* [[Histologic:Chapter 5#Cardiac_Muscle|Cardiac Muscle]]<br />
|group6 = [[Histologic:Chapter 6|Chapter 6]]<br />
|list6 =<br />
* [[Histologic:Chapter 6#Introduction|Introduction]]<br />
* [[Histologic:Chapter 6#Nerve_Fibers_And_Nerves|Nerve Fibers And Nerves]]<br />
* [[Histologic:Chapter 6#Central_Nervous_System:_Brain|Central Nervous System: Brain]]<br />
* [[Histologic:Chapter 6#Spinal_Cord_-_General_Structure|Spinal Cord - General Structure]]<br />
* [[Histologic:Chapter 6#Sympathetic_Chain_Ganglion_With_Multipolar_Neurons|Sympathetic Chain Ganglion With Multipolar Neurons]]<br />
* [[Histologic:Chapter 6#Parasympathetic_Ganglia|Parasympathetic Ganglia]]<br />
|group7 = [[Histologic:Chapter 7|Chapter 7]]<br />
|list7 =<br />
* [[Histologic:Chapter 7#Introduction|Introduction]]<br />
* [[Histologic:Chapter 7#Blood_Smears|Blood Smears]]<br />
|group8 = [[Histologic:Chapter 8|Chapter 8]]<br />
|list8 =<br />
* [[Histologic:Chapter 8#Introduction|Introduction]]<br />
* [[Histologic:Chapter 8#Lymph_Nodes|Lymph Nodes]]<br />
* [[Histologic:Chapter 8#Thymus|Thymus]]<br />
* [[Histologic:Chapter 8#Tonsils|Tonsils]]<br />
* [[Histologic:Chapter 8#Spleen|Spleen]]<br />
|group9 = [[Histologic:Chapter 9|Chapter 9]]<br />
|list9 =<br />
* [[Histologic:Chapter 9#Introduction|Introduction]]<br />
* [[Histologic:Chapter 9#Small_Blood_Vessels|Small Blood Vessels]]<br />
* [[Histologic:Chapter 9#Medium-Sized_Blood_Vessels|Medium-Sized Blood Vessels]]<br />
* [[Histologic:Chapter 9#Large_Arteries|Large Arteries]]<br />
* [[Histologic:Chapter 9#Large_Veins|Large Veins]]<br />
|group10 = [[Histologic:Chapter 10|Chapter 10]]<br />
|list10 =<br />
* [[Histologic:Chapter 10#Olfactory_Area|Olfactory Area]]<br />
* [[Histologic:Chapter 10#Epiglottis|Epiglottis]]<br />
* [[Histologic:Chapter 10#Trachea|Trachea]]<br />
* [[Histologic:Chapter 10#Bronchi,_Bronchioles,_and_Lung|Bronchi, Bronchioles, and Lung]]<br />
|group11 = [[Histologic:Chapter 11|Chapter 11]]<br />
|list11 =<br />
* [[Histologic:Chapter 11#Lip|Lip]]<br />
* [[Histologic:Chapter 11#Tongue|Tongue]]<br />
* [[Histologic:Chapter 11#Salivary_Glands|Salivary Glands]]<br />
* [[Histologic:Chapter 11#Pancreas|Pancreas]]<br />
* [[Histologic:Chapter 11#Esophagus|Esophagus]]<br />
* [[Histologic:Chapter 11#Stomach|Stomach]]<br />
* [[Histologic:Chapter 11#Small_Intestine|Small Intestine]]<br />
* [[Histologic:Chapter 11#Pylorus-Duodenal_Junction|Pylorus-Duodenal Junction]]<br />
* [[Histologic:Chapter 11#Duodenum|Duodenum]]<br />
* [[Histologic:Chapter 11#Jejunum|Jejunum]]<br />
* [[Histologic:Chapter 11#Ileum|Ileum]]<br />
* [[Histologic:Chapter 11#Appendix|Appendix]]<br />
* [[Histologic:Chapter 11#Colon|Colon]]<br />
* [[Histologic:Chapter 11#Rectum|Rectum]]<br />
* [[Histologic:Chapter 11#Anal_Canal|Anal Canal]]<br />
|group12 = [[Histologic:Chapter 12|Chapter 12]]<br />
|list12 =<br />
* [[Histologic:Chapter 12#Introduction|Introduction]]<br />
* [[Histologic:Chapter 12#Gallbladder|Gallbladder]]<br />
|group13 = [[Histologic:Chapter 13|Chapter 13]]<br />
|list13 =<br />
* [[Histologic:Chapter 13#Skeletal_Muscle|Skeletal Muscle]]<br />
* [[Histologic:Chapter 13#Cartilage|Cartilage]]<br />
* [[Histologic:Chapter 13#Bone|Bone]]<br />
* [[Histologic:Chapter 13#Joints|Joints]]<br />
|group14 = [[Histologic:Chapter 14|Chapter 14]]<br />
|list14 =<br />
* [[Histologic:Chapter 14#Introduction|Introduction]]<br />
* [[Histologic:Chapter 14#Pituitary_Gland_(Hypophysis)|Pituitary Gland (Hypophysis)]]<br />
* [[Histologic:Chapter 14#Thyroid|Thyroid]]<br />
* [[Histologic:Chapter 14#Parathyroid|Parathyroid]]<br />
* [[Histologic:Chapter 14#Suprarenal_(Adrenal)_Glands|Suprarenal (Adrenal) Glands]]<br />
* [[Histologic:Chapter 14#Endocrine_Pancreas_(Pancreatic_Islets_of_Langerhans)|Endocrine Pancreas (Pancreatic Islets of Langerhans)]]<br />
|group15 = [[Histologic:Chapter 15|Chapter 15]]<br />
|list15 =<br />
* [[Histologic:Chapter 15#Kidney|Kidney]]<br />
* [[Histologic:Chapter 15#Ureter_and_Urinary_Bladder|Ureter And Urinary Bladder]]<br />
|group16 = [[Histologic:Chapter 16|Chapter 16]]<br />
|list16 =<br />
* [[Histologic:Chapter 16#Introduction|Introduction]]<br />
|group17 = [[Histologic:Chapter 17|Chapter 17]]<br />
|list17 =<br />
* [[Histologic:Chapter 17#Introduction|Introduction]]<br />
|group18 = [[Histologic:Chapter 18|Chapter 18]]<br />
|list18 =<br />
* [[Histologic:Chapter 18#Introduction|Introduction]]<br />
|group19 = [[Histologic:Chapter 19|Chapter 19]]<br />
|list19 =<br />
* [[Histologic:Chapter 19#Introduction|Introduction]]<br />
|group20 = [[Histologic:Contributors|Contributors]]<br />
|list20 =<br />
* [[Histologic:Contributors#Acknowledgements|Acknowledgements]]<br />
* [[Histologic:Contributors#Staff|Staff]]<br />
<br />
}}<noinclude><br />
<br />
[[Category:Histologic Templates]]<br />
[[Category:Histologic]]<br />
</noinclude></div>Matthew Andersonhttps://peir.path.uab.edu/index.php?title=Histologic:Chapter_15&diff=3231Histologic:Chapter 152014-07-18T05:35:37Z<p>Matthew Anderson: /* Ureter And Urinary Bladder */</p>
<hr />
<div>== Kidney ==<br />
<br />
A good knowledge of normal kidney histology is essential for the understanding of various diseases of the kidney. <br />
<br />
=== Slide 117, Kidney (Masson) ===<br />
<br />
Observe Slide 117, kidney (Masson) with the unaided eye to distinguish the lighter stained medulla from the more peripheral and darker-staining cortex. Now, with low and medium powers of the microscope identify:<br />
<br />
*The thin, fibrous capsule of the kidney. Scan the entire slide to observe that the only prominent connective tissue fibers within the kidney are in association with blood vessels.<br />
<br />
*The cortex containing the renal corpuscles.<br />
<br />
*The medulla in which renal corpuscles are lacking.<br />
<br />
*The larger blood vessels at the corticomedullary junction. These are arcuate arteries and veins.<br />
<br />
Study the cortex of the kidney for details of its organization. On Slide 114, Slide 116, Slide 117, and Slide 118 identify:<br />
<br />
Pars radiata (medullary rays) are columns of straight tubules extending from the cortex into the medulla and from the medulla into the cortex. <br />
<br />
The straight segments of the proximal and distal tubules and the straight collecting tubules are located here.<br />
<br />
Pars convoluta (cortical labyrinths) areas occupy the region between pars radiata.<br />
<br />
Within the pars convoluta can be found renal corpuscles, proximal convoluted tubules (PCT), distal convoluted tubules (DCT), and blood vessels (the interlobular arteries and veins and the afferent and efferent arterioles). A kidney lobule consists of a pars radiata and “half” of each adjoining pars convoluta.<br />
<br />
Learn to distinguish the PCT from the DCT. With the light microscope the straight portion of the proximal tubule is histologically similar to the PCT and the straight portion of the distal tubule is similar to the DCT.<br />
<br />
Proximal convoluted tubule (PCT). The PCT may be up to 14 mm in length. This is more than twice as long as the average DCT, which is about 5 mm long. Thus, one sees more sections through PCT in any given region of the pars convoluta than through DCT.<br />
<br />
*The PCT stains darker than the DCT.<br />
<br />
*The PCT cells are larger and the cytoplasm is more granular than the cells of the DCT. This is due to the large number of mitochondria in the cytoplasm of the PCT cells.<br />
<br />
*The cell boundaries of the PCT are less distinct than the DCT because the membranes of the PCT cells are more highly interdigitated with the membranes of neighboring cells. And the PCT is larger in cross section than the DCT.<br />
<br />
*The apical surface of the PCT exhibits microvilli, about 1.2 μm in length, which form a brush border when observed with the light microscope. This border disintegrates quickly when postmortem changes set in. A brush border is lacking on cells of the DCT although the EM demonstrates the presence of a few microvilli.<br />
<br />
*The cells of the PCT are low columnar to pyramidal; those of the DCT are more cuboidal in shape.<br />
<br />
<peir-vm>UAB-Histology-00117</peir-vm><br />
<br />
==== Slide 114, Kidney ====<br />
<peir-vm>UAB-Histology-00114</peir-vm><br />
==== Slide 116, Kidney ====<br />
<peir-vm>UAB-Histology-00116</peir-vm><br />
<br />
=== Slide 118, Kidney (PASH) ===<br />
<br />
The renal corpuscles on Slide 118, Kidney (PASH) are to be studied in detail.<br />
<br />
First, with low power, become oriented to the section on Slide 118. This is a tangential section through the cortex of the kidney. Thus, renal corpuscles are found throughout the. Note that tubules in the pars radiata are cut in cross section and appear to be grouped into bundles surrounded (or bordered) by pars convoluta. We will study these tubules in detail later.<br />
<br />
On high power study several renal corpuscles on Slide 118. A renal corpuscle ranges from 150 to 250 μm in diameter. It consists of a tuft of capillaries called the glomerulus and a surrounding epithelial capsule called the glomerular capsule (Bowman’s capsule). This latter structure has an outer layer of simple squamous epithelial cells with a basement membrane. The cells and basement membrane form the parietal layer of Bowman’s capsule, which surrounds Bowman’s space or the urinary space. A layer of visceral epithelial cells covers the glomerular basement membrane. The cells of this highly modified epithelial layer are called podocytes because of numerous foot-like processes (pedicels) that they possess. The space between the visceral and parietal layers of Bowman’s capsule is termed Bowman’s space or urinary space within which the glomerular filtrate is collected and passes into the PCT. The parietal epithelial cells are continuous with the neck of the PCT and with the visceral layer at the vascular pole.<br />
<br />
Identify:<br />
<br />
*The simple squamous epithelial cells of the parietal layer.<br />
*The basement membrane on which the cells lie.<br />
*The urinary space.<br />
<br />
The glomerulus is a specialized bed of capillaries connecting an afferent arteriole with an efferent arteriole at the vascular pole of the renal corpuscle. The urinary pole of the renal corpuscle where the glomerular filtrate passes into the PCT usually lies opposite the vascular pole. <br />
<br />
Find, if present, a renal corpuscle sectioned so as to demonstrate both the vascular and urinary poles.<br />
<br />
Study several glomeruli in detail.<br />
<br />
*A glomerulus appears lobulated since the looped capillaries from a major capillary branch are grouped together. About 5-8 major capillary trunks (lobules) are formed in each glomerulus. Up to 50 capillary loops may be present.<br />
<br />
*Anastomoses occur between capillaries of the same lobule and of different lobules.<br />
<br />
*The afferent arteriole supplying blood to the glomerulus is usually larger than the efferent arteriole.<br />
<br />
*The endothelial cells lining the capillary lumen are fairly large, attenuated, flattened cells with nuclei bulging into the lumen. The fenestrated endothelium has numerous pores that vary from 50 to 100 nm in diameters. These endothelial cells are only partially surrounded by a basement membrane that is about 300 nm thick in adults. The capillaries of each lobule wind around a common axis that appears as a cellular stalk of mesangial cells and mesangial matrix. Basement membrane is lacking between the capillary endothelium and the stalk of the capillary lobule occupied by the mesangial cells and mesangial matrix. Hence, instead of surrounding the entire lumen of a capillary loop, the basement membrane is reflected onto adjacent capillary loops. The mesangial cells are located inside of the basement membrane of the capillary lobule, and they are in direct contact with the endothelial cells where basement membrane material is lacking.<br />
<br />
*Identify the nuclei of endothelial cells, mesangial cells lying in mesangial matrix, and the nuclei of podocytes.<br />
<br />
On Slide 118 select, an “open appearing” capillary loop cut in cross section, lying towards the outer edge of a glomerulus and within which a nucleus can be seen bulging into the lumen. This is the nucleus of an endothelial cell. The nuclei tend to lie on the wall of the capillary loop nearest the central axis.<br />
<br />
Find a slightly darker staining nucleus, about the same size as the endothelial nucleus, embedded in the denser, darkly stained PAS-positive material. This is a mesangial cell nucleus and the PAS-positive staining material is mesangial matrix. The mesangial cell lies to the inner side of the basement membrane. Electron micrographs show that the mesangial cells are in direct contact with the endothelial cells. The mesangial matrix produced by the mesangial cells is a basement membrane-like material that increases with age and in certain disease states such as diabetic nephropathy and glomerulonephritis.<br />
<br />
Identify slightly larger, slightly paler staining nuclei lying outside the basement membrane. They are podocyte nuclei. The interdigitated cytoplasmic extensions of the podocytes, which line the outside of the basement membrane, can be seen only with the electron microscope.<br />
<br />
Filtration Barrier. In order for substances in the blood to reach the urinary space as glomerular filtrate they must pass through the filtration barrier. This important barrier includes the endothelium of the capillary, basal lamina and slit pores between adjacent pedicles (foot processes) of the podocytes. The slit pores are about 250 nm in diameter and they are bridges by a thin diaphragm called the filtration slit membrane.<br />
<br />
Identify on Slide 117 the endothelial cells of the glomerular capillary, the mesangial cells and mesangial matrix, and the podocytes. On this section stained with Masson’s stain the basement membrane of the glomerulus appears as a very thin blue line. The mesangial matrix is readily identified as the purplish-staining material between capillaries.<br />
<br />
Juxtaglomerular apparatus. On Slide 118 attempt to find a juxtaglomerular apparatus where the distal tubule comes into close association with the afferent glomerular arteriole at the vascular pole of each Bowman’s capsule. This composite structure consists of the macula densa of the distal tubule, lacis cells (extraglomerular mesangial cells) and juxtaglomerular cells (JG cells). The latter cells are modified smooth muscle cells in the tunica media of the afferent arteriole. These secretory, epithelioid cells replace the smooth muscle cells of the media only in the localized region of the juxtaglomerular apparatus. The JG cells are separated from the cells forming the macula densa only by a basal lamina. The JG cells are important since they secrete renin.<br />
<br />
The macula densa is identified as being an area of tall, slender cells on the side of the distal tubule adjacent to the afferent arteriole. Since the cells are narrow, the nuclei appear closely packed together, and with the light microscope the area appears denser than surrounding areas (macula densa = “dense spot”). The function of these cells is to monitor sodium in the distal tubule and “pass” this information to the JG cells to alter their secretory activity.<br />
<br />
The lacis cells are small agranular cells lying in a triangular area bounded by the afferent and efferent arterioles and the macula densa. The lacis cells are embedded in a dense network of basement membranes. They are continuous with the mesangium of the capillary stalk. The specific function of lacis cells is not well understood, although it has been associated with the secretion of erythropoietin.<br />
<br />
Study the tubules in the medulla of the kidney on Slides 114, 116, and 117. A straight collecting tubule lying in the pars radiata of the cortex receives 7 to 10 arched collecting tubules as it passes into the outer zone of the medulla. Continuing into the inner zone of the medulla the straight collecting tubules unite with other similar tubules to form large papillary ducts. These open into the minor calyces at the area cribrosa of a renal papilla. Papillary ducts are not found in the outer zone of the medulla. The straight collecting tubules have a diameter of about 40μm as compared with a diameter of 200 μm for the papillary ducts.<br />
<br />
On Slide 117 identify straight collecting tubules in the medulla. They exhibit a lining of large pale staining, simple columnar cells with well-defined cell boundaries. <br />
<br />
Identify the smallest tubules cut in cross section in the medulla. These are the thin segments of the loops of Henle. Only the juxtamedullary nephrons have thin segments extending deep into the medulla. The thin segments of Henle’s loop are easily confused with capillaries or venules. They are composed of a single layer of flattened epithelial cells having round to ovoid nuclei that tend to bulge into the lumen. The cells sit on a basement membrane. The overall diameter of the segment is about 15μm, and cross sections of them usually contain 3 to 5 nuclei. Remember that the loops of Henle are made up of both thick and thin segments. The thick segments form descending and ascending limbs. An abrupt change occurs in the epithelium where the thick segments meet the thin segments.<br />
<br />
Return to Slide 118 and identify the collecting ducts in the pars radiata. They have many nuclei in cross section and have distinctly visible cell boundaries. In the pars convoluta the proximal convoluted tubules are easily identified by the PAS-positive staining of their brush border. The straight portion of the proximal tubule in the pars radiata appears similar. The straight portions of the distal tubules (thick ascending segment of Henle’s loop) located in the pars radiata appear to have undergone more postmortem change than other parts of the tubule. The straight distal tubules exhibit cells that are somewhat disrupted and pulled free of the basement membrane. Many cells appear to be “floating” within the lumen of the tubule. Identify the straight proximal and distal tubule.<br />
<br />
Blood supply<br />
<br />
The circulation of blood through the kidney is rather complex and should be studied in your textbook before attempting to understand it from slides. Only a few aspects of the overall circulation can be seen on any one microscopic slide.<br />
<br />
On Slide 117 identify the arcuate arteries and the arcuate veins at the corticomedullary junction. The arteries are continuations (branches) of the larger interlobar arteries.<br />
<br />
Each arcuate artery gives off several interlobular arteries that pass perpendicularly through a pars convoluta to the surface of the kidney. Identify interlobular arteries on Slide 117; they are very small arteries or arterioles. Thin-walled interlobular veins (mostly venules) are seen adjacent to some of the interlobular arteries. The arteries and veins pass more or less through the middle of a pars convoluta. The area between two interlobular arteries and veins is a kidney lobule. On Slide 118 identify interlobular arteries cut in cross section and lying within a pars convoluta. A number of afferent glomerular arterioles are given off by the interlobular artery before it terminates as a capillary bed beneath the capsule of the kidney.<br />
<br />
On Slide 117 identify the erythrocytes in capillaries that are interspersed between the convoluted tubules. In the outer cortex, the capillaries originate from the efferent arterioles to form a peritubular plexus, which in the living condition appears to bathe the tubules in blood. The capillaries drain into cortical venules that empty into interlobular veins that accompany the interlobular arteries.<br />
<br />
The efferent arterioles leaving glomeruli near the medulla are relatively larger than the efferent arterioles in the outer cortex. They extend into the medulla as the arteriolae rectae spuriae. Pursuing a straight course in the medulla, these vessels give rise to capillary nets that extend deeply into the papillae. Veins called venae rectae return the blood to the arcuate veins. Collectively the blood supply of the medulla in which these thin-walled vessels make hairpin loops is called the vasa rectae.<br />
<br />
Interstitial connective tissue. The connective tissue of the kidney is not nearly as extensive as in other organs. Most of the prominent connective tissue is in association with blood vessels, lymphatics and nerves. The more delicate and looser connective tissue spreads through the renal parenchyma. It is more abundant in the medulla than in the cortex. This poorly developed interstitial tissue consists principally of reticular and collagenous fibers with associated fibroblasts and macrophages. Observe on Slide 117 (Masson) that the large blood vessels are invested with the densest connective tissue, the adventitia. Very delicate collagen fibers can be seen surrounding tubules in the medulla. They appear as a pale blue network. Reticular fibers also form a diffuse network around the tubules. Compare the amount of interstitial connective tissue in the medulla with the amount present around the convoluted tubules of the cortex. The interstitial diseases of the kidney form from or directly affect the interstitial tissue. In severe systemic infections, non- specific inflammatory changes can occur in the interstitium.<br />
<br />
The sinus of the kidney is the concave indentation or potential cavity on the hilus side of the kidney. It lies adjacent to kidney cortex of the renal columns and to medulla. It contains loose connective tissue and fat. In it are embedded branches of the renal artery and vein, lymphatics, nerves, minor calyces, major calyces and the renal pelvis.<br />
<br />
<peir-vm>UAB-Histology-00118</peir-vm><br />
<br />
=== Slide 92, Kidney, Ureter, Vessels ===<br />
<br />
Study Slide 92. Section through the sinus of the kidney showing several blood vessels, nerves, and a section of ureter, all embedded in loose connective and adipose tissue (H&E).<br />
<br />
<peir-vm>UAB-Histology-00092</peir-vm><br />
<br />
== Ureter and Urinary Bladder ==<br />
<br />
=== Ureter ===<br />
<br />
The ureters conduct urine from the kidneys to the bladder. They are about 12 inches long, course behind the peritoneum, and consist of three layers (a mucosa, a muscularis and a fibrosa).<br />
<br />
==== Slide 120, Ureter (Masson) ====<br />
<br />
Study Slide 120, Ureter (Masson), which is a cross section through the lower one-third of the ureter. At low and medium power observe:<br />
<br />
The mucosa consisting of transitional epithelium and a lamina propria. Note the stellate-shaped lumen formed by the folds of the lamina propria, the density of the lamina propria, and the thickness of the epithelium.<br />
<br />
The muscularis has three layers of smooth muscle since this section was taken from the lower one-third of the ureter. The upper two-thirds of the ureter has only two layers of smooth muscle in the muscularis. Identify, here, an inner longitudinal layer with fibers cut in cross section, the middle circular layer and an outer longitudinal layer. It is this outer layer that is the “extra layer” of the lower ureter. Note how the muscle bundles are separated by abundant connective tissue.<br />
<br />
Identify the fibrosa lying outside the muscularis. This loose connective tissue layer binds the ureter to adjoining structures. Observe the blood vessels running through the fibrosa, which also contains nerves, lymphatics and fat cells.<br />
<br />
<peir-vm>UAB-Histology-00120</peir-vm><br />
<br />
==== Slide 119, Ureter (H&E) ====<br />
<br />
Examine Slide 119, Ureter (H&E) under low and medium power for most of the features just studied on Slide 120. In addition, note that:<br />
<br />
*With H&E, the muscle layers do not contrast well with the connective tissue fibers. Hence, it is difficult to distinguish that the middle portion of the ureter from which this section was taken has only two muscle layers instead of three. These are an inner longitudinal layer and an outer circular layer. <br />
<br />
*Note the abundance of adipose tissue in the fibrosa. Identify the small arteries and veins occurring in this layer.<br />
<br />
*Study the mucosa of slide 119 at high power.<br />
<br />
It consists of a transitional epithelium of 5 to 6 cell layers thick. The surface cells of transitional epithelium, called cap cells, are larger and stain more darkly than the underlying cells. In some areas, the surface cells are stretched so as to appear almost squamous. The epithelium rests on a basement membrane, but the membrane is so thin that it is only identified with the electron microscope.<br />
<br />
The lamina propria is a rather dense-appearing connective tissue layer between the epithelium and the muscularis. It contains collagenous fibers, elastic fibers and connective tissue cells. In the Masson-stained ureter, Slide 120, venules and capillaries are more readily seen within the lamina propria than they are in Slide 119.<br />
<br />
Study the muscularis on Slide 119. This section is from the middle ureter that has only two layers of smooth muscle, an inner longitudinal and an outer circular layer. Contraction of the smooth muscle aids in passing the urine through the ureters.<br />
<br />
<peir-vm>UAB-Histology-00119</peir-vm><br />
<br />
=== Urinary Bladder ===<br />
<br />
The urinary bladder consists of a mucosa, a muscularis and an adventitia that is either a fibrosa (where it blends with the connective tissue of surrounding structures) or a serosa (found only on the superior surface where the bladder is covered with peritoneum).<br />
<br />
==== Slide 121, Urinary Bladder (H&E) ====<br />
<br />
Scan the slide with low and medium powers to identify the three major layers. <br />
<br />
Study the mucosa for details. A lining of transitional epithelium and underlying lamina propria form the mucosa. The empty bladder usually has a folded mucosa, the distended bladder a smooth one. Examine the epithelium in different regions of this section. In the relaxed bladder, as seen here, the epithelium is six or more cell layers thick; whereas in the distended bladder the epithelium is so stretched it appears to be only two or three cell layers thick. Recall that the epithelium is a special type of stratified epithelium that undergoes “transitional changes” to allow for the filling and emptying of the bladder.<br />
<br />
Examine the surface cells. Observe in some regions their dome-shaped apices, and how they appear to “cap” the smaller underlying cells. These cap cells are occasionally binucleated. They are stretched into a “squamous” layer in the distended bladder. The cells immediately beneath the surface cells are pear-shaped or flask-shaped and their apices fit into facet-like indentations on the underside of the surface cells. The basal layer cells undergo mitosis to replenish the surface cells sloughed off into the lumen of the urinary bladder.<br />
<br />
The luminal plasma membrane of the surface cells is thicker than most plasma membranes. This specialization, in conjunction with the superficial layer of cytoplasm containing numerous tonofilaments (microfilaments), serves to protect the epithelium from the hypertonicity of the urine, prevents urine resorption and acts as a barrier to the loss of water from the cells into the hypertonic urine.<br />
<br />
The connective tissue underlying the transitional epithelium is the lamina propria. It is mostly collagenous fibers in which some elastic networks occur. Lymphocytes wander through the lamina propria and an occasional solitary lymphatic nodule can be present (but it is unlikely that you will see one on our slides). Observe that the deeper region of the lamina propria gives rise to an extensive capillary bed beneath the epithelium.<br />
<br />
The muscularis of the bladder has three layers of smooth muscle indistinctly arranged into an inner longitudinal layer, a middle circular layer, and an outer longitudinal layer. The middle circular layer is the thickest but this may be difficult to identify on your slides, since the different muscle bundles tend to interlace and anastomose. Observe the abundant connective tissue that separates bundles of muscle. The muscularis has an abundant blood supply with an extensive capillary network.<br />
<br />
Adventitia. This section of bladder is covered by a serosa consisting of a surface mesothelium. <br />
<br />
<peir-vm>UAB-Histology-00121</peir-vm> <br />
<br />
{{Template:Histologic}}<br />
<br />
[[Category:Histologic]]</div>Matthew Anderson