Reproduction Histo Lab Male Reproduction Lab
This laboratory is concerned with the identification of the histological features of the male reproductive system. It includes a study of the following components: Testes, Efferent Ducts, Epididymus, Seminal Vesicle, Prostate Gland and Penis..Be able to distinguish each of these structures and their salient features.
Testis. This image is a low magnification through a testis illustrating several seminiferous tubules cut in cross-section (X). The seminiferous tubules are embedded in a loose connective tissue, the interstitium, containing collagen fibers, loose connective cells, and Leydig cells. The area encircled in red is enlarged on the next page.
Leydig Cells. This is a high magnification of the previous image illustrating Leydig cells (arrows) located between the seminiferous tubules. These cells secrete androgens and are under the influence of Interstitial Cell Stimulating Hormone (ICSH). Since they are steroid-producing cells, the cytoplasm often appears vacuolated.
Seminiferous Tubule. The yellow arrow points to the interstitium located between the seminiferous tubules. Lining the outer portion of the seminiferous tubules are spermatogonia (red arrows). They give rise to primary spermatocytes (green arrows). These cells are larger than spermatogonia and are usually in an extended meiotic division as evidenced by the presence of chromosomes. Primary spermatocytes give rise to secondary spermatocytes (not identified). Secondary spermatocytes remain as such for very short period of time and are difficult to distinguish from the next stage, spermatids (orange arrows). The spermatids may be found in various stages of spermiogenesis. Sertoli cells (black arrows) are roughly columnar in shape and extend from the outer portion of the wall of the seminiferous tubule to the luminal surface. The cytoplasm does not stain well, so identification is based on their nuclei. Their nuclei are light-staining and contain a prominent nucleolus. Sertoli nuclei are usually oval in shape with the long axis being perpendicular to the rim of the wall. For purposes of this laboratory, you need only to identify: spermatogonia, primary spermatocytes, spermatids, spermatozoa (not illustrated) and Sertoli cells.
Seminiferous Tubule. In this image of seminiferous tubule, several cell types are illustrated. The red arrows point to spermatogonia. The cells encircled in red appear to be spermatogonia in mitosis. The cells encircled in green are primary spermatocytes. The cells encircled in black are examples of spermatids. A small blood vessel is shown in the interstitium (green arrow) along with a Leydig cell (black arrow).
Seminiferous Tubule. This is another image of the wall of the seminiferous tubule illustrating several cell types: Sertoli cells (black arrows), spermatogonia (red arrows), primary spermatocytes (green arrows) and spermatids (encircled in black). By convention, spermatozoa are not identified as such until they are released into the lumen as a result of the apical degeneration of the Sertoli cells.
Seminiferous Tubule. This is another image of the wall of the seminiferous tubule illustrating several cell types: Can you identify the spermatogonia, primary spermatocytes, and the spermatids?? The cells encircled in black are spermatids in the late stages of spermiogenesis. A few nuclei of spermatozoa (red arrows) can be identified in the lumen of the tubule.
Straight Tubules (tubuli recti). This is section through several straight tubules. The seminiferous tubules from each lobule join to form a single straight tubule. All of the straight tubules empty into the rete testis located in the mediastinum testis. Straight tubules are lined entirely by Sertoli cells.
Straight Tubules (tubuli recti). This is another image illustrating portions of two straight tubules (S.T.) lined by Sertoli cells. A portion of a seminiferous tubules is shown on the right.
Rete Testes. This is a section through the mediastinum testes (encircles in black) illustrating the rete testes (black arrows). The mediastinum testes contains a dense connective tissue (red arrows) and is the posterior extension of the tunica albuginea. The rete testes is a an extensive labyrinth of anastomosing, very irregular channels that receive the contents of the straight tubules. Rete are lined by a simple cuboidal epithelium.
Rete Testes. This is a higher magnification of the previous image illustrating the rete testes. The red arrows point to the simple cuboidal epithelial lining.
Efferent Ducts. 8-15 efferent ducts transport the spermatozoa from the rete testes to the epididymus located on the posterior aspect of the testes. The epithelial lining contains groups of simple cuboidal cells alternating with groups of simple columnar cells. Some of the cells contain cilia. These ciliated cells are the only motile lining cells in the entire duct system. The efferent ducts form the head of the epididymus. The ductus epididymus empties into the ductus (vas) deferens.
Epididymus. The efferent ducts collect and join as a single, highly coiled ductus epididymus, measuring 5-7- meters in length. The ductus epididymus forms the body and the tail of the epididymus. What forms the “head”?? This duct is lined by a pseudostratified columnar epithelium. The columnar cells contain stereocilia that increase the surface area for absorption, i.e., spermatozoa are “concentrated” in this portion of the duct system. Spermatozoa are stored in the tail portion of the epididymus until ejaculation.
Epididymus. This is a higher magnification of the ductus epididymus illustrating the tall epithelial cells containing stereocilia. There is a thin layer of circularly arranged smooth muscle cells around the outer part of the tubule. The entire epididymus is covered with dense connective tissue containing smooth muscle cells.
Epididymus. This is high magnification of the previous image illustrating a portion of the ductus epididymus. Note the stereocilia. What is their function? The lumen contains spermatozoa. Connective tissue with smooth muscle cells are present outside the tubule
Seminal Vesicle. Each seminal vesicle is a tortuous elongated diverticulum off of the ductus deferens just posterior to the prostate gland. The wall of the seminal vesicle contains circularly and longitudinally arranged smooth muscle cells. The mucosa contains tall folds that branch into secondary and tertiary folds (right image-encircled in red and yellow). Many of the folds merge with one another to form compartments. The epithelial lining is usually pseudostratified columnar.
Seminal Vesicle. This is high magnification of the previous image. Note the compartmentalization of the mucosa as a result of the merging of the mucosal folds. Note also the thick wall of the gland containing lots of smooth muscle.
Prostate Gland. The prostate gland surrounds the urethra at its origin. It consists of an aggregate about 30-50 compound tubuloavleolar glands embedded in a dense fibromuscular stroma containing lots of smooth muscle. The black arrows point to the lumen of the glands. The lumen of many of the glands contain prostatic concretions or corpora amylacea (red arrows), especially in older men.. The concretions are usually of varied size and shape. They are believed to be formed by precipitation of secretory material and may calcify.
Prostate Gland. This is high magnification of a portion of a prostatic gland showing the thick fibromuscular wall containing smooth muscle. The mucosa contains epithelium that varies from simple cuboidal to simple columnar depending upon the activity level of the gland. Two prostatic concretions are present (arrows).
Penis. This is high magnification of a cross-section of penis. The corpora cavernosa (CC) are enveloped in a dense connective tissue, the tunica albuginea (TA). The corpus spongiousum (CS) is illustrated with the urethra (U) in the center.
FEMALE REPRODUCTION LABORATORY This laboratory is concerned with the identification of the histological features of the female reproductive system. It includes a study of the following components: Ovaries, containing follicles in different stages of development, Uterine tubes, Uterine Endometrium, and Placenta. Be able to distinguish each of these structures and their salient features.
Ovary. This image is section through the cortical region of an ovary. It is lined by germinal epithelium (black arrows) which contains cuboidal cells. The tunica albuginea (red arrow) is a dense connective tissue layer lying deep to the germinal epithelium. Deep to the tunica albuginea is a small collection of primordial follicles (green arrows).
Primordial Follicles. This image is a higher magnification of the previous image illustrating a group of primordial follicles (arrows). Primordial follicles contain primary oocytes surrounded by a single layer of squamous "follicular" cells.
Primary Follicle. The first sign of follicular development is the enlargement of the squamous cells (surrounding the primary oocyte) into cuboidal cells. A primary oocyte surrounded by a single layer of cuboidal cells is classified as a Primary Follicle. The development of a Zona Pellucida (arrow) is evident in the micrograph.
Multilaminar Primary Follicle. As a result of continued stimulation by FSH, the follicular cells undergo mitotic activity and form multiple layers of cells. Such a follicle is now classified as a Multilaminar Primary Follicle (arrow). The development of the theca folliculi is also evident at this stage.
Multilaminar Primary Follicle. This is a higher magnification of a multilaminar primary follicle. This follicle is characterized as having a primary oocyte surrounded by several layers of follicular cells. A zona pellucida (red arrow) separates the follicular cells from the primary oocyte. The black arrow points to the developing theca folliculi.
Secondary Follicle. As the follicles increase in size, small pools of fluid (arrows) accumulate among the granulosa (follicular) cells characterizing Secondary Follicles. These small pools will eventually coalesce into a single pool called an antrum. The black arrow points to the theca folliculi. The area in yellow is enlarged on the next page.
Theca Folliculi. This is a higher magnification of a section of the tissue illustrated on the previous page. The black line shows the separation of the granulosa cells (G) and the theca folliculi. At this magnification the theca externa (red arrow) can be distinguished from the theca interna (green arrow).