OBJECTIVES:

1. Understand and identify the stages of follicular growth (primordial, primary, secondary, tertiary), as well as the changes that occur in the follicular wall during pregnancy.
2. Identify the regional variations in the structure of the oviduct.
3. Describe the changes that occur in the ovary and oviduct during the menstrual cycle.

The female reproductive system is composed of highly specialized organs which are in a state of constant change, from the sequential alterations characteristic of each menstrual cycle to the dramatic changes that occur during pregnancy. You will examine the ovary which contains the germ cells or oocytes, the oviduct (Fallopian tube) which receives the ovum at ovulation and conducts it to the uterus where a fertilized egg may implant. At term, the fetus passes through the uterine cervix and the vagina to the external environment.

I. OVARY (W pgs 360-7, 19.3-12)
Slide 239 (ovary, monkey, H&E) [WinLab] [Mac] [WinHome]
Slide 269 (ovary, monkey, PAS) [WinLab] [Mac] [WinHome]
Slide 269-2 (ovary, monkey, PAS) [WinLab] [Mac] [WinHome]
Slide 235 (ovary, human, H&E) [WinLab] [Mac] [WinHome]
Slide 234 (ovary, human, H&E) [WinLab] [Mac] [WinHome]
Slide 234-2 (ovary, human, trichrome) [WinLab] [Mac] [WinHome]
Slide 236a (ovary, human, H&E) [WinLab] [Mac] [WinHome]

The ovaries are paired organs situated on either side of the uterus. They are attached on one edge, the hilus, to the broad ligament of the uterus by a fold of peritoneum, the mesovarium. Using slide 239, examine the overall topography of the ovary and note the numerous vessels which enter it via the broad ligament. The inner medulla (present in most slides) is highly vascular and composed of a loose connective tissue core. Examine the outer cortex of the ovary which is composed of stroma and numerous follicles in various stages of development. In slide 239, note the layer of collagenous connective tissue, the tunica albuginea [example] just below the surface epithelium (mesothelium/serosa often misleadingly referred to as "germinal epithelium") that covers the ovary. (W pg 362, 19.4)

Examine the stroma of the cortex in slide 239 and note the whorls of closely-packed, spindle-shaped fibroblasts. The cortex also contains many oocytes (300,000- 400,000 at birth) embedded in this cortical stroma. Because of the variation in sectioning, age and stage of the cycle, you will have to study several slides in order to study all aspects of follicular development, atresia and corpus luteum formation (see W page 364, 19.7).

Examine several primordial follicles [example] using slide 239 or 269 and note that they consist of a large oocyte surrounded by a layer of flattened follicular cells. Next examine the appearance of primary follicles [example] in which the large oocyte is surrounded by a layer of cuboidal follicular cells (also good in slide 238). These follicular cells proliferate to form a loose multi-layer, the granulosa cell layer. A rim of neutral glycoprotein, the zona pellucida (clear zone), surrounds the oocyte separating it from the surrounding granulosa cells. Slide 269 has been stained with PAS, so that carbohydrates and connective tissue are highlighted. Using this slide, examine the zona pellucida [example] of several smaller follicles. Stromal cells form a dense sheath (theca) around the follicle.

Examine the structure of several secondary follicles [example] and observe that between the stratified granulosa cells there are large lacunae that coalesce to form the follicular antrum. The stromal cells surrounding the follicle have differentiated to form an inner layer (theca interna) of plump cells that secrete steroid precursors and an outer layer (theca externa) composed of concentrically arranged stromal cells that provide support for the developing follicle (W pg 363, 19.5). Slide 235 also has good theca layers (see below).

With continued development, the follicle becomes a Graafian or ovulatory follicle [example] [CAVEAT]. The granulosa zone now consists of many layers of cuboidal follicular epithelial cells located at the periphery of the large, well-formed follicular antrum. The oocyte has attained its full size, is located eccentrically within the follicle in a small hillock, the cumulus oophorus which protrudes into the antrum. The zona pellucida is surrounded by a continuous layer of follicular cells, the corona radiata. What is the purpose of the corona radiata? (FE1) Because of its size, the oocyte will not be present in every section of the follicle, but examine the other components of a tertiary follicle. The theca interna is separated from the granulosa cells by a distinct basement membrane. Theca externa cells are densely packed, spindle-shaped cells which blend with the theca interna cells and with the surrounding stroma. Note that the theca interna has a rich capillary vascular supply, particularly well demonstrated in slide 235 [example] (W pg 363, 19.6, see also the diagram in R pg 779, 23.7a).

Because the contents of only one follicle are usually ovulated at a time in humans, other follicles which have been stimulated to develop must degenerate, or undergo atresia [example] (W pg 366, 19.10). Atresia is not limited to mature follicles, but may begin at any stage in follicular development. Early atretic alterations include: clumping of the nuclear chromatin (pyknosis) and shrinkage and lysis of the cytoplasm of the oocyte, granulosa or follicular cells. Examine the pyknotic granulosa cells [example], which are sloughed into the follicular antrum. The basement membrane that separates the granulosa cells from the theca interna may also thicken considerably to form a so-called “glassy membrane.” These changes are especially well illustrated in H&E slide 234 [example] and trichrome-stained slide #234-2 [example]. Make sure you are able to differentiate atretic changes from artifacts related to shrinkage due to fixation. Macrophages may eventually invade the center of the larger atretic follicles that are finally replaced by loose connective tissue.

After ovulation, the follicle which housed the ovum collapses and becomes highly infolded and invaded by vessels, forming the corpus luteum [example] (yellow body) (W pgs 365-6, 19.8-9; R pg 783, 23.11). Examine slide 236a and observe that the corpus luteum appears pale and very folded. If the egg is fertilized and implants, the corpus luteum enlarges to become the corpus luteum of pregnancy. Examine the inner granulosa lutein cells [example] (formed from the remaining granulosa cells) and the outer theca lutein cells [example] which come from the remaining theca interna cells. Both cell types are polyhedral and filled with lipid droplets and have centrally located nuclei. The theca lutein cells are, however, considerably smaller, more darkly staining and have fewer lipid filled vacuoles than the granulosa lutein cells. They are found most prominently in the infoldings right up against the granulosa lutein layer. Granulosa lutein cells contain a pigment, lipochrome, which produces the yellowish color of the corpus luteum in an unfixed ovary. A central blood clot may be present in recently ovulated follicles.

If the egg is not fertilized, the corpus luteum degenerates, and is gradually infiltrated with collagen and a few (if any) fibroblasts, forming the corpus albicans (white body) (W pg 360, 19.3; W pg 367, 19.11; R pg 784, 23.13) particularly evident in slide 234 stained with H&E [example] and trichrome [example]. The corpus albicans is also formed during the later half of pregnancy when the placenta takes over steroid secretion from the corpus luteum. Excellent examples of corpus albicans can be best observed in slides 234 or 236. What is the morphological difference between the corpus albicans and an atretic follicle? (FE2) What is the correlation between the follicular stage and the ovarian stage during the menstrual cycle? (FE3)

II. OVIDUCTS (FALLOPIAN or UTERINE TUBES) (W, pgs 367-8, 19.13-14)
Slide 240-1 (oviduct, infundibulum, H&E) [WinLab] [Mac] [WinHome]
Slide 240-2 (oviduct, ampulla, H&E) [WinLab] [Mac] [WinHome]
Slide 241even (oviduct, isthmus, H&E) [WinLab] [Mac] [WinHome]
Slide 241odd (oviduct, uterine segment, H&E) [WinLab] [Mac] [WinHome]

The oviduct conducts the ovulated egg from the peritoneal cavity to the uterus over a period of approximately three days, during which fertilization and segmentation of the zygote occurs. There are striking regional variations in the oviducts that reflect:

1) the trapping of the egg,
2) a region where fertilization takes place, and
3) a region simply for transport to the uterus.

Examine its open end near the ovary, the infundibulum [example], in slide 240-1 and note the funnel shape and ridges of mucosa that extend as a fringe of finger-like projections known as fimbriae. Note the ciliated cells that cover the fimbria that help sweep the egg into the oviduct. Move on to slide 240-2 to trace the passage of the egg from the infundibulum through the numerous longitudinal folds of the ampulla [example] recalling that this is where fertilization usually occurs. Next is the isthmus region in slide 241even [example] that is characterized by tall branching ridges of mucosa which project into and partially fill the lumen of the oviduct. Note the numerous non-ciliated secretory (peg) cells and the ciliated cells that line the lumen. The isthmus contains tall folds and few ciliated cells, while the interstitial (or intramural because it's within the uterine wall) segment, shown in slide 241odd, [example] has low ridges and a preponderance of secretory cells. Observe that as you progress from the infundibulum where there is a large lumen filled with many mucosal folds toward the uterus, the overall luminal diameter decreases, as does the number of ciliated cells, while the proportion of smooth muscle in the muscular layer gradually increases.

Examine the loose connective tissue of the lamina propria using slide 241even. Next study the circular, oblique, and sparse longitudinal layers of smooth muscle (defining the layers will be difficult!). It has been suggested that this muscle may play a two-fold role; first, in distending the oviduct toward the ovary to aid in “capturing” the ovum; and second, in producing peristaltic waves which help propel the ovum toward the uterus. The outermost layer of the oviduct, the serosa, is highly vascular and is composed of mesothelium and thin underlying connective tissue that is continuous with the broad ligament.

ELECTRON MICROGRAPH WALL CHARTS

#135 OVARY [WinLab] [Mac] [WinHome]

Note the considerable difference in size between primordial follicles and the secondary follicle. Note also the presence of several capillaries in the thecal layer, and the highly organized appearance of the follicle.

#133 OVARY [WinLab] [Mac] [WinHome]

In this low magnification view of a secondary follicle, examine the characteristics of the thecal layer, granulosa cells, corona radiata, and the ooplasm. Note particularly the basal lamina which separates the thecal and granulosa cell layers and the acellular zona pellucida that surrounds the oocyte.

#134 OVARY [WinLab] [Mac] [WinHome]

Higher magnification view of another secondary follicle. Note the penetration of the zona pellucida by processes from the oocyte and from the granulosa cells of the corona radiata. One current theory regarding follicular atresia suggests that contact of the ooplasm by granulosa cells is required for continued follicular development and that, if lost, atresia results.

REVIEW QUESTION ANSWERS

FE1: What is the purpose of the corona radiata?

FE2: What is the morphological difference between the corpus albicans and an atretic follicle?

FE3: What is the correlation between the follicular stage and the ovarian stage during the menstrual cycle?

OBJECTIVES:

1. Distinguish the cyclical alterations in the uterine endometrium and understand their hormonal bases.
2. Describe the alterations and functional changes in the cytology of the cervix and vagina during the menstrual cycle, and during pregnancy.

III. UTERUS (W pgs 369-75, 19.15-21; R pg 793, 23.19)
Slide 244 (uterus, prolifereative phase, H&E) [WinLab] [Mac] [WinHome]
Slide 243 (uterus, early secretory phase, H&E) [WinLab] [Mac] [WinHome]
Slide 245-1 (uterus, secretory phase, H&E) [WinLab] [Mac] [WinHome]
Slide 245-2 (uterus, menstrual phase, H&E) [WinLab] [Mac] [WinHome]

The uterus is a pear-shaped, hollow organ partially covered by peritoneum. Examine the overall topographical organization of the uterus from its outer serosal or adventitial covering, through the thick muscular layer (myometrium) to the mucosa (endometrium) in slide 243 (this slide is actually at a stage between proliferative and secretory).

The myometrium [example] of the uterus is composed of interwoven bundles of smooth muscle supported by dense connective tissue. Examine their arrangement into indistinct bundles, with several bundles running roughly parallel to the long axis of the body of the uterus. During pregnancy, the muscle fibers elongate, proliferate and produce collagen in response to hormonal stimulation.

The endometrium [example] is divided into two layers or strata and consists of a simple columnar epithelium and an underlying stroma that contains tubular glands that may branch near the myometrium. The stratum functionale or functional layer is the thicker, outer layer that is sloughed off with menstruation. The underlying stratum basale or basal layer is retained throughout the menstrual cycle and serves as the regenerative source of the stratum functionale. The endometrium undergoes striking cyclical modifications that depend on sequential hormonal alterations. Compare specimens from proliferative and secretory phases with the menstrual phase. In what way do the secretory cells of the uterus change at ovulation? (FE4)

Proliferative Phase (days 5-14; W pg 370, 19.15; pg 372, 19.18)
In slide 244 [WinLab] [Mac] [WinHome], the proliferative phase is underway and glands have proliferated and cover the surface. Although difficult to see in these sections, spiral arteries [example] are elongated and convoluted, and extend from the basal layer into the functional layer.

Secretory Phase (days 15-28; W pg 373, 19.19)
In slide 245-1 [WinLab] [Mac] [WinHome], observe that the glands of the secretory phase endometrium appear convoluted. Toward the end of this phase, apical tissues become ischemic and glands take on a characteristic “saw tooth” appearance [example]. The endometrium reaches its maximal thickness during this period, and spiral arteries continue to grow and extend into the superficial regions of the functional layer. There is also considerable leukocyte infiltration in the stroma.

Menstrual Phase (days 1-4; W pg 371, 19.16)
In slide 244-2 [WinLab] [Mac] [WinHome], much of the stratum functionalis has sloughed away, and amongst the debris are numerous blood cells (RBCs and leukocytes). Notice that the stratum basalis remains intact.

IV. UTERINE CERVIX (W pgs 376, 19.23-24; R pgs 797-9, 23.22-4)
Slide 249 (cervix, H&E) [WinLab] [Mac] [WinHome]
UCSF slide 405 (cervix, trichrome) [WinLab] [Mac] [WinHome]

The uterine cervix shown in slide 249 is continuous with both the body of the uterus and the upper portion of the vagina. Note that the wall has considerable smooth muscle and much dense connective tissue. Note also the number of collagen fibers in the stroma.

The mucosa is lined by a tall columnar mucus-secreting epithelium in its uterine portion, but note the abrupt change to stratified squamous epithelium at its vaginal face. This stratocolumnar junction which should be readily identifiable in both slide 249 [example] and UCSF slide 405 [example] is frequently the site of pre-neoplastic and neoplastic (cervical cancer) changes. The mucosa is thrown into deep irregular folds known as plicae palmitae (palmate folds). During the majority of the uterine cycle these glands secrete a highly viscous mucus forming a barrier to microorganisms, while at mid-cycle (ovulation) the mucus becomes more hydrated, which facilitates sperm entry. Blockage of the openings of the cervical mucosal glands frequently results in the accumulation of secretory products within the glands, leading to the formation of dilated Nabothian cysts which may be seen in USCF slide 304 [example]. These cysts are generally benign; however, they can become clinically relevant should they become enlarged enough to cause obstruction of the cervical canal.

V. VAGINA (W pg 377, 19.26; R pg 802, 23.28-29)
Slide 250-1 (vagina, H&E) [WinLab] [Mac] [WinHome]
Slide 250-2 (vagina, trichrome) [WinLab] [Mac] [WinHome]

The vagina connects the female reproductive system to the exterior of the body. At low magnification, note its three-layered structure: the mucosal lining, smooth muscle layer, and outer adventitial layer. The epithelium that lines the vagina is stratified squamous, which appears slightly vacuolated due to the presence of glycogen in these cells, which is removed during fixation.

The connective tissue of the thick lamina propria [example] contains many elastic and collagen fibers throughout and many small veins in the deeper region. The subjacent smooth muscle layers [example] are arranged in poorly defined inner circular and predominant outer longitudinal layers; it may be easier to discern the smooth muscle from the surrounding connective tissue in the trichrome-stained section [example]. The connective tissue (seen particularly well in sections stained with trichrome) of the outer adventitial layer also contains many elastic fibers, thus contributing to the overall distensibility of this region. Also evident in the adventitia in both H&E [example] and trichrome-stained sections [example] are parasympathetic ganglia that innervate the erectile tissue (i.e. the numerous small veins) of the lamina propria.

REVIEW QUESTION ANSWERS

FE4: In what way do the secretory cells of the uterus change at ovulation?

OBJECTIVES:

1. Understand the histological basis of implantation and placentation.
2. Identify the cells that form mature chorionic villi.
3. Describe the immature and mature placental barriers.

VI. PLACENTA (slides 253, 255; W pgs 378-84, 19.27-33)
Slide 253 (placenta, early, H&E) [WinLab] [Mac] [WinHome]
Slide 255_20x (placenta, late, H&E) [WinLab] [Mac] [WinHome]
Slide 255_40x (placenta, late, H&E) [WinLab] [Mac] [WinHome]

With the implantation of a zygote into the uterus, a number of changes take place in the endometrium. Cells from the embryonic trophoblast invade the uterine mucosa, secretions from these cells coalesce to form lacunae in the endometrium, which is now termed the decidua. These spaces also contain maternal blood. The trophoblast rapidly invades the decidua forming primary villi, that contain only trophoblast (outer syncytiotrophoblast and inner cytotrophoblast) cells. Mesenchyme and blood vessels form the core of the secondary villi. During the second half of pregnancy the cytotrophoblast cells disappear and the capillary basal lamina fuses with that of the syncytiotrophoblast to improve exchange.

Begin with slide 253 [WinLab] [Mac] [WinHome], which is early placenta. The entire field is filled with villi cut predominantly in cross section. Mesenchymal tissue and fetal blood vessels (filled with fetal RBCs which, in the early stages of fetal hematopoiesis, still have nuclei) make up the core of each villus which is covered by a trophectoderm shell [example] of inner cytotrophoblast and outer syncytiotrophoblast cells. The syncytiotrophoblast cells are more eosinophilic and have smaller nuclei. As the name implies, these cells result from the fusion of many cells and thus have many nuclei per cell and no discernable lateral boundaries. In contrast, cytotrophoblast cells are clearly demarcated, have a single, large nucleus and sometimes a more basophilic cytoplasm. Notice that there is almost a complete ring of cytotrophoblast cells covering each villus in the early placenta --these cells are thought to function as stem cells for the formation of the syncytiotrophoblast, which is why they may disappear later in pregnancy.

Next, study slide 255 [WinLab] [Mac] [WinHome], which is a late placenta. Although you will be able to see an occasional cytotrophoblast cell, you will not be able to see forming villi in this late placenta. Examine the trophectoderm shell [example] which now consists of multinucleate syncytiotrophoblast cells located on the outer surface of the villi as well as an occasional residual underlying cytotrophoblast cell. The nuclei of the syncytiotrophoblast cells often form aggregates of so-called "syncytial knots" [example] that may look like specks of dirt when viewed at lower magnification. Syncytiotrophoblast cells that are bathed in maternal blood have apical surfaces specialized for absorption (microvilli), pinocytosis, and exocytosis and an appearance typical of secretory cells. Also examine the numerous macrophage-like (Hofbauer) cells [example] that can be found within the connective tissue of the placental villi. These cells are characteristically large, with elliptical, eccentric nuclei and extensively vacuolated cytoplasm. What layers must nutrients cross to get from maternal to fetal blood in early and late pregnancy? (FE5)

Large quantities of an amorphous eosinophilic substance, fibrinoid [example], may also be deposited in the intervillus space in this older placenta. This material clings to the villus surface and may bind several villi together. The amount of fibrinoid in combination with the appearance of the connective tissue in the villi can be used to stage the placenta.

ELECTRON MICROSCOPE WALL CHARTS

#135 PLACENTA - Terminal villus [WinLab] [Mac] [WinHome]

Examine the ultrastructure of the syncytiotrophoblast cells, particularly their external surface. Note the paucity of cytotrophoblast cells at this stage of development. Be certain that you know the components of the placental barrier, how they may change during pregnancy and why.

REVIEW QUESTION ANSWERS

FE5: What layers must nutrients cross to get from maternal to fetal blood in early and late pregnancy?

1. Be able to identify the components of the mammary gland:
   1. Nipple and areola
   2. Lobes and lobules
   3. Lactiferous ducts and sinuses
   4. Secretory alveoli (acini)
   5. Intralobular and interlobular connective tissue
   
   
2. Identify and describe the histological differences in the mammary gland:
   
   1. Prior to pregnancy in adult females (inactive)
   2. During pregnancy and lactation (active)
   
   
3. Understand the multiple, cellular mechanisms involved in the formation and release of milk.

VII. MAMMARY GLAND

Like the other tissues in the female reproductive system, alterations in circulating hormone levels result in histologically demonstrable changes in the mammary gland.

A. Inactive mammary gland (W, pg 387, 19.38)
Slide 259 (inactive mammary gland) [WinLab] [Mac] [WinHome]

In slide 259, using low power observe the glandular lobules [example] consisting of a few clusters of small ducts and intralobular connective tissue. Examine the size, number and structure of the ducts. Some sections contain a well-preserved lactiferous duct [example]. Many appear to be composed of 2 layers of cuboidal epithelium. The outer layer of cells is, in fact, a layer of myoepithelial cells whereas the inner layer are cuboidal ductal epithelial cells. The interlobular connective tissue [example] which makes up the majority of the gland is a mass of dense, fibrous connective tissue. Compare intralobular and interlobular connective tissue. What is the difference between the two? (FE6)

B. Active mammary gland (Slide 258; H&E; W, pgs 388, 19.37-39)
Slide 258 (active mammary gland, H&E) [WinLab] [Mac] [WinHome]
Slide 261 (mammary gland, active, H&E) [WinLab] [Mac] [WinHome]

This tissue was probably taken from an individual before the last trimester. When compared with the inactive mammary gland, you can see that the intralobular ducts have proliferated to form additional secretory regions. Both the epithelial cells and myoepithelial cells increase in number. Alveoli [example] have formed, their epithelial cells have large, clear areas of apical cytoplasm, a region occupied by glycogen and lipid. Note the increased cellularity of the intralobular connective tissue. Note also that not all lobules within the gland have proliferated to the same degree. In many sections, portions of a large excretory, lactiferous duct [example] are present. The epithelial lining is again two layered, the bottom layer being principally myoepithelium. Compare the morphology of the inactive and active gland. Observe the intralobular connective tissue and note the abundance of plasma cells [example]. These plasma cells are the source of secretory IgA.

VIII. NIPPLE AND AREOLA (W pg 386, 19.36-7)
Slide 265 (nipple and areola, H&E) [WinLab] [Mac] [Winhome]

On this slide, the distinction between the nipple and areola should be made by holding the slide up to the light (the histological differences are minimal). Note the covering epithelium contains a great deal of melanin that is responsible for the macroscopic pigmentation of these areas. The epithelium exhibits a fair, but irregular, number of deep rete pegs [example]. Sebaceous glands are present to a variable extent, especially in the areola. Occasional glands (Glands of Montgomery) that resemble sweat glands or rudimentary mammary glands (there is a controversy) may be present in the areola on a very few of our glass slides (the virtual slide does NOT contain any glands of Montgomery). Note that the dense irregular connective tissue of the dermis is interrupted by numerous fascicles of smooth muscle [example] that insert into the dermal connective tissue (much like arrector pili muscles). These muscle bundles are responsible for erection of the nipples. Occasional nerves are also present in the dermis. The lactiferous ducts [example] are lined by stratified squamous epithelium near the opening and the lumens are frequently filled with desquamated cells. Deeper in the connective tissue, the ducts acquire a stratified columnar appearance that is really a cuboidal duct cell sitting on a myoepithelial cell.

ELECTRON MICROGRAPH WALL CHART
#88 MAMMARY GLAND (lactating) --sorry, not available online right now but check back soon!
Review the difference in releasing mechanisms between milk lipid droplets and milk protein particles. Milk protein secretion occurs through exocytosis, while milk lipid secretion is through apocrine secretion. Make sure you know which mechanism relates to what product.

REVIEW QUESTION ANSWERS
FE6: What is the difference between intralobular and interlobular connective tissue?

Endocrine/Reproductive Systems Sample Questions

1. Which of the following cell types commonly has prominent lipid droplets in the cytoplasm?

1. cells of the adrenal medulla
2. theca lutein cells
3. parathyroid chief cells
4. Sertoli cells
5. thyroid parafollicular cells (C-cells)
6. acidophils of the anterior pituitary

ANSWER

Click here to view low magnification image.
Click here to view high magnification image.
2. The asterisk (*) is in the lumen of:

1. ductus (vas) deferens
2. efferent duct
3. epididymis
4. penile urethra
5. uterine (or intramural) segment of oviduct
6. cervical canal

ANSWER

Click here to view low magnification image.
Click here to view high magnification image.
3. The tissue shown is:

1. normal thyroid gland
2. hypoactive thyroid gland
3. hyperactive thyroid gland
4. inactive mammary gland
5. active mammary gland
6. prostate gland
7. seminal vesicle

ANSWER

Click here to view image.
4. Hypothyroidism may be caused by malfunction of which cell type shown in this drawing of the anterior pituitary?

1. A
2. B
3. C
4. D
5. E

ANSWER

Click here to view region (note: the region of interest is shown when the window opens)
5. The tissue in the region shown is from:

1. penis, corpus cavernosum
2. penis, corpus spongiosum
3. early placenta
4. late (term) placenta
5. seminal vesicle
6. ductus (vas) deferens

ANSWER

Click here to view low magnification image.
Click here to view high magnification image.
6. The tissue shown:

1. produces LH
2. produces FSH
3. will develop into an atretic follicle
4. will develop into a corpus albicans
5. ALL of the above

ANSWER

Click here to view low magnification image.
Click here to view high magnification image.
7. The cell indicated by the arrow in the high magnification image secretes:

1. immunoglobulin A (IgA) dimers
2. calcitonin
3. thyroid hormone (T₃ or T₄)
4. testosterone
5. luteinizing hormone
6. prostate specific antigen

ANSWER

Click here to view image.
8. By convention, the ploidy (n) and DNA content (c) of a quiescent, diploid somatic cell is said to be 2n, 2c. The ploidy and DNA content of the cell indicated in the micrograph is:

1. 2n, 4c
2. 1n, 2c
3. 2n, 2c
4. 1n, 2c
5. 1n, 1c

ANSWER

Click here to view image.
9. The layer of cells indicated:

1. converts into granulosa lutein cells after ovulation.
2. is derived from the theca interna
3. is removed from the oocyte when ovulation occurs.
4. makes contact with the oocyte via gap junctions.
5. develops into trophoblast cells if fertilization and implantation occur.

ANSWER

Click here to see image
10. The cell indicated in the light micrograph in panel A and in the electron micrograph in panel B may secrete which of the following possible products?

1. thyroid hormone
2. thyroid stimulating hormone
3. calcitonin
4. parathyroid hormone
5. testosterone
6. epinephrine or norepinephrine
7. glucocorticoids
8. progesterone

ANSWER