Histology Mentor

Reproductive System - Questions 110-122

110. Question - Diagram the changes that occur in the endometrium during the menstrual cycle.

111. Question - Illustrate and label the components of the mature ovarian follicle. Explain the significance of differentiating germ line cells from somatic cells.

Somatic cells contain the full complement of 46 chromosomes and replicate by mitosis. Differentiation of germ line cells results ultimately in the formation of ova or sperm having only 23 chromosomes. This is the result of two meiotic divisions, a reductional division followed by an equational division. The oocyte in all ovarian follicles is a primary oocyte arrested in in prophase of the first meiotic division. It does not complete that division and become a secondary oocyte until ovulation occurs.

112. Question - Diagram the changes that occur in a recruited primordial ovarian follicle that lead to the formation of a secondary follicle.

The primordial oocyte is surrounded by a very thin layer of squamous cells but when it is recruited these cells enlarge and become cuboidal. Subsequently it becomes multiple layers and eventually the antrum forms. This contains the liquor folliculi or follicular fluid. This is a secondary follicle. The oocyte remains a primary oocyte arrested in prophase of the first meiotic division but grows considerably until ovulation occurs.

113. Question - Identify three features besides ovarian follicles that can be found in the ovaries of a young woman and explain their significance.

Corpus luteum is derived from the granulosa cells and the theca interna cells of the ovarian follicle after ovulation. The theca lutein cells produce precursor steroids that are used by the granulosa lutein cells to make progesterone. Progesterone stimulates the uterine glands to enter their secretory phase.

Corpus albicans is a scar that develops when the corpus luteum degenerates.

Glassy membranes are the thickened basement membranes of atretic follicles. Since many follicles are recruited each cycle but only one follicle normally ovulates, many follicles degenerate.

114. Question - Describe the structure and function of the uterine tube.

The uterine tube (fallopian tube) begins near the ovary as multiple, finger-like fimbria. These fimbria are extensions of the complex, branched, longitudinal, mucosal folds that characterize its ampulla. The folds become simple ridges in the isthmus of the uterine tube near the uterus. There are no glands in the very cellular lamina propria and there is no muscularis mucosae. Diffuse lymphoid tissue and epithelial lymphocytes are common.

The epithelium covering the mucosa throughout the tube is simple columnar with two types of cells. Patches of ciliated cells are interspersed with nonciliated secretory cells. The cilia beat toward the uterus. The secretions support the germ cells while in transit.

The muscularis consists of an inner longitudinal and outer circular layer. Near the uterus a third outer longitudinal layer is added. The muscularis of the isthmus is considered to be the pacemaker of uterine contractions.

115. Question - Diagram the uterine cervix and the vagina identifying the epithelia found in each. In which epithelium does cervical cancer usually arise?

116. Question - Illustrate the structure of the testis naming its component parts.

117. Question - Diagram the cells that make up the epithelium of the seminiferous tubule.

118. Question - Diagram and label the major components of the spermatozoan.

119. Question - Describe the cells in the testis that make and those that respond to testosterone. How is testosterone production regulated?

The interstitial cells of Leydig are found between the folds of the seminiferous tubules. Their cytoplasm is characterized by having an abundance of smooth endoplasmic reticulum and mitochondria with tubular cristae. Many lipid droplets are also a feature of these cells.

Testosterone secretion is regulated by interstitial cell stimulating hormone, ICSH (Same as luteinizing hormone) from the gonadotrophs (basophils) of the pituitary gland. Testosterone is required for development of the seminiferous tubule epithelium. In addition the Sertoli cells are stimulated by follicle stimulating hormone to produce a testosterone-binding protein which helps to concentrate the testosterone in the seminiferous tubule.

120.Question - Describe the structure and explain the function of the efferent ductules and the epididymis.

The efferent ductules (8-12 of them) empty individually into the singular duct of the epididymis at the head of the epididymis. The efferent ductules have a pseudostratified epithelium with longitudinal ridges of columnar ciliated cells alternating with troughs of non-ciliated cuboidal cells that have apical microvilli. Consequently, in cross-section, the luminal border appears scalloped, but the basement membrane presents a smooth circular contour.

The two main functions of the efferent ductules are transport of sperm to the epididymis and reabsorption of testicular fluid.

By contrast, the epididymis is larger in diameter and its epithelium consits of a uniformly columnar pseudostratified epithelium presenting a smooth luminal contour. However, rather than cilia, these tall columnar cells have elongated, branched microvilli. Because these microvilli superficially resemble cilia they are given the name stereocila. Spermatozoa are frequently seen clumped at the center of the lumen. This duct is very convoluted in the head and body regions but straightens out in the tail region at the inferior pole of the testis, where it is continuous with the vas deferens. The thickness of the smooth muscle layer increases gradually from head to tail of the epididymis, then abruptly dramatically thickens at the origin of the vas deferens.

The two main functions of the epididymis are 1) storage of sperm and 2) profiding nutritional and biochemical support for sperm maturation.

121.Question - List the components of the spermatic cord. Describe the vas deferens and its termination.

The spermatic cord consists of the structures that pass through the inguinal canal along with loops of skeletal muscle, the cremaster. The testicular artery and the pampiniform venous plexus accompany the vas deferens in the spermatic cord.

The vas deferens has a thick smooth muscle wall organized in three layers - inner and outer longitudinal and middle circular layers. The mucosa has a very cellular lamina propria without glands or muscularis mucosae. The epithelium is similar to that in the duct of the epididymis but not as tall. There are longitudinal mucosal ridges which near the termination in the ampulla become expanded and branched and in addition anastomose with each other. The vas deferens terminates by joining the seminal vesicle to give rise to the ejaculatory duct that passes through the prostate gland to open into the urethra.

122.Question - Describe the seminal vesicle and explain its function. Make a diagram that shows the relationships of the prostate gland to the urethra.

The seminal vesicle is a coiled blind-ended tube with a thick muscular wall. Its complex mucosal folds are covered by a pseudostratified columnar epithelium which produces a thick secretion rich in fructose, an important nutrient for spermatozoa.

In the prostate gland the periurethral glands are the site of hyperplasia that causes age related urethral obstruction. Cancer most often is associated with the prostate gland proper.

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