TBL22 - Female Genital Organs

Question 1

What forms the broad ligament? What is the ovarian ligament?

Answer 1

1) Parietal peritoneum drapes over the uterus and uterine tubes like a sheet thereby forming the broad ligament (ignore its subdivisions)
2) The ovarian ligament (aka ligament of the ovary) is a fold of the broad ligament that tethers the ovaries to the uterus and forms the surface epithelium of the ovaries

Question 2

What is the suspensory ligament of the ovary and what does it allow passage for? Where do the round ligaments travel?

Answer 2

1) The suspensory ligament of the ovary is an elongation of the broad ligament that provides passage to ovarian vessels and accompanying nerves from the lateral pelvic wall
2) The round ligaments pass from the uterus to the deep inguinal rings

Question 3

Where are the uterus and ovaries located within the pelvic cavity? What forms the superior two thirds of the uterus? What forms the inferior third of the uterus?

Answer 3

1) The uterus is centered in the pelvic cavity and the ovaries are positioned laterally midway to the lateral pelvic walls
2) The body and rounded fundus superior to the ostia of the uterine tubes form the superior two thirds of the uterus
3) The cylindrical cervix forms the inferior third of the uterus

Question 4

Where is the uterus held in relation to the bladder? What is the cervix suspended from and by what? What does this account for?

Answer 4

1) The uterus is anteverted onto the superior wall of the empty bladder thereby providing passive support to the uterus
2) The cervix is suspended from the wall of the pelvic cavity by the cardinal ligament
3) Thus, the resulting passive support accounts for cervical immobility

Question 5

What artery do the uterine and vaginal arteries arise from? What conveys the arteries to their respective viscera?

Answer 5

1) The uterine and vaginal arteries arise from the internal iliac artery
2) The arteries are conveyed to the respective viscera by the cardinal ligament

Question 6

What conditions contribute to prolapse of a retroverted uterus?

Answer 6

Instead of pressing the uterus against the bladder, increased intra-abdominal pressure tends to push the retroverted uterus, a solid mass positioned upright over the vagina (a flexible, hollow tube), into or even through the vagina

Question 7

Which pelvic structure must be identified to preclude its damage or obstruction during surgical ligation of the uterine artery?

Answer 7

The ureter

Question 8

What do the ovarian arteries arise from and where do they travel?

Answer 8

After arising from the abdominal aorta, the ovarian arteries descend on the posterior abdominal wall to the suspensory ligaments of the ovary

Question 9

What do the ovarian arteries supply? What do the ovarian arteries anastomose with and what does this anastomosis provide?

Answer 9

1) The ovarian arteries supply the ovaries and distal uterine tubes
2) The ovarian arteries anastomose with branches of the uterine and vaginal arteries to provide a collateral circulation for the ovaries, uterine tubes, uterus, and vagina

Question 10

What do the uterine veins drain into?

Answer 10

The uterine veins drain into the internal iliac veins

Question 11

Where does lymph from the ovaries drain into? Where does lymph from the uterine tubes, uterine body, and cervix mainly drain into?

Answer 11

1) Lymph from the ovaries drains into the lumbar lymph nodes

2) Lymph from the uterine tubes, uterine body, and cervix drains mainly into the internal iliac lymph nodes

Question 12

What structures are above the pelvic pain line? What structure is below the pelvic pain line?

Answer 12

1) The ovaries, uterine tubes, fundus and body of the uterus are above the pelvic pain line
2) The cervix is below the pelvic pain line

Question 13

How does cervical cancer metastasize to the bladder or the brain?

Answer 13

1) Because no peritoneum intervenes between the anterior cervix and the base of the bladder, cervical cancer may spread by contiguity to the bladder
2) It may also spread by lymphogenous (lymph borne) metastasis to external or internal iliac or sacral nodes
3) Hematogenous (blood borne) metastasis may occur via iliac veins or via the internal vertebral venous plexus

Question 14

How does regional anesthesia differ after injection of anesthetic agents into the subarachnoid space at L3/L4 (spinal anesthesia) and after a caudal epidural block? Why can a severe headache occur only with the spinal anesthesia?

Answer 14

1) Spinal anesthesia, in which the anesthetic agent is introduced with a needle into the spinal subarachnoid space at the L3–L4 vertebral level, produces complete anesthesia inferior to approximately the waist level. Because the anesthetic agent is heavier than cerebrospinal fluid, it remains in the inferior spinal subarachnoid space while the patient is inclined. The anesthetic agent circulates into the cerebral subarachnoid space in the cranial cavity when the patient lies flat following the delivery. A severe headache is a common sequel to spinal anesthesia.
2) The caudal epidural block is a popular choice for participatory childbirth. Within the sacral canal, the anesthesia bathes the S2–S4 spinal nerve roots, including the pain fibers from the uterine cervix and superior vagina, and the afferent fibers from the pudendal nerve. With epidural anesthesia, no “spinal headache” occurs because the vertebral epidural space is not continuous with the cranial extradural (epidural) space

Question 15

Where do bilateral gonads form? What do the gonads initially appear as?

Answer 15

1) Bilateral gonads form in the intermediate mesoderm medial to the mesonephros
2) The gonads initially appear as a pair of longitudinal genital ridges

Question 16

Where do epiblast-derived primordial germ cells travel and temporarily reside?

Answer 16

Epiblast-derived primordial germ cells pass through the primitive streak and temporarily reside among endodermal cells in the yolk sac wall

Question 17

Where do the epiblast-derived primordial germ cells migrate to after residing in the yolk sac? What happens to the genital ridge epithelium once germ cells arrive?

Answer 17

1) From the yolk sac, the germ cells migrate along the dorsal mesentery of the hindgut to the genital ridges
2) After arrival of the germ cells, the genital ridge epithelia invaginate to form primitive sex cords that characterize the indifferent gonads

Question 18

What is the fate of the sex cords in females? What are follicular cells formed by and what do they form?

Answer 18

1) In females, the sex cords degenerate
2) Follicular cells, formed by continued proliferation of the surface epithelium, surround germ cell-derived oogonia to form primary follicles, which transform the indifferent gonads into the ovaries

Question 19

What prevents indifferent gonad differentiation in the genital ridges?

Answer 19

1) During the fourth week of embryonic development, the primordial germ cells migrate by ameboid movement along the dorsal mesentery of the hindgut, arriving at the primitive gonads at the beginning of the fifth week and invading the genital ridges in the sixth week
2) If they fail to reach the ridges, the gonads do not develop. Hence, the primordial germ cells have an inductive influence on development of the gonad into ovary or testis

Question 20

Where do the ovaries descend from and to during degeneration of the mesonephros?

Answer 20

During degeneration of the mesonephros, the ovaries descend from their upper lumbar origins into the pelvic cavity

Question 21

In both sexes, what forms the paramesonephric (mullerian) ducts and where do they course in relation to the mesonephric ducts? Where do proximal ends of the paired paramesonephric ducts open directly into?

Answer 21

1) In both sexes, longitudinal invaginations of the gonadal ridge epithelia form the paramesonephric (aka mullerian) ducts that course parallel to the mesonephric ducts
2) Proximal ends of the paired paramesonephric ducts open directly into the peritoneal cavity

Question 22

What happens to the paramesonephric ducts during ovarian dissension? Progressive growth of the uterine canal transforms it into what?

Answer 22

1) Ovarian dissension into the pelvis moves the middle portions of the paramesonephric ducts mediocaudally and their distal portions fuse in the midline to form the uterine canal
2) Progressive growth transforms the uterine canal into the fundus, body, and cervix of the uterus

Question 23

What forms the uterine tubes and what structure do the uterine tubes perforate? What does this allow for continuity of?

Answer 23

1) The proximal and middle portions of the paramesonephric ducts form the uterine tubes that perforate the wall of the uterine body
2) This thereby establishes continuity of the uterine lumen with the peritoneal cavity

Question 24

What parts of the mesonephric ducts disappear in females?

Answer 24

Other than distal portions of the mesonephric ducts and the ureteric buds, which are absorbed into the wall of the bladder, the mesonephric ducts degenerate and essentially disappear in females

Question 25

What happens to the paramesonephric ducts in males and why? What happens to the paramesonephric and mesonephric ducts in females and why?

Answer 25

1) In males, the paramesonephric ducts completely regress by testicular production of mullerian inhibiting substance (MIS)
2) In females, persistence of the paramesonephric ducts results from the lack of MIS and degeneration of the mesonephric ducts results from the absence of testosterone production

Question 26

Why can peritonitis cause salpingitis and why is the latter a major cause of female infertility?

Answer 26

1) Because the female genital tract communicates with the peritoneal cavity through the abdominal ostia of the uterine tubes, infections of the vagina, uterus, and tubes may result in peritonitis
2) Conversely, inflammation of a tube (salpingitis) may result from infections that spread from the peritoneal cavity. A major cause of infertility in women is blockage of the uterine tubes, often the result of salpingitis

Question 27

Why is primary peritonitis rare in females?

Answer 27

1) While theoretically it is possible for organisms to enter the female peritoneal cavity directly via the uterine tubes, such primary peritonitis is rare, bearing testimony to the effectiveness of the protective mechanisms of the female reproductive tract
2) A primary mechanism in preventing such infection is a mucous plug that effectively blocks the external os (opening) of the uterus to most pathogens, but not to sperms

Question 28

What is a bicornate uterus?

Answer 28

1) One of the relatively common anomalies of the uterus is the uterus bicornis, in which the uterus has two horns entering a common vagina
2) The fusion process of the upper part of the Paramesonephric ducts is altered
3) As a result the caudal part of the uterus is unitary while the cephalo (upper) part is bifurcated

Question 29

At birth, how many primary (primordial) follicles do the ovaries contain? What forms the ovarian surface epithelium and what is unique about this tissue?

Answer 29

1) At birth, the ovaries contain about 400,000 primary (primordial) follicles
2) Germinal epithelium incorrectly labels the peritoneal fold that forms the ovarian surface epithelium, which lacks a germinal function but accounts for 90% of ovarian cancers

Question 30

What do several primary follicles transform into during each menstrual cycle? On the other hand, what is required for differentiation of secondary follicles and what do they differentiate into?

Answer 30

1) Several primary follicles transform into secondary (developing) follicles during each menstrual cycle
2) Several cycles are required for the differentiation of secondary follicles into mature (aka Graafian) follicles

Question 31

What does a mature follicle do during each cycle? What does an ovulated follicle become? If pregnancy does not occur, what is the fate of the corpus luteum?

Answer 31

1) During each cycle, one mature follicle normally ovulates
2) An ovulated follicle becomes a corpus luteum
3) If pregnancy does not occur, the corpus luteum degenerates and is replaced by a fibrous scar called a corpus albicans

Question 32

What is the fate of mature follicles that fail to ovulate? When does atresia begin and what is its effect on the number of primary follicles by the start of puberty? After puberty, is atresia still present? How many follicles ovulate between puberty and menopause?

Answer 32

1) Mature follicles that fail to ovulate become atretic (degenerating) follicles
2) Atresia begins at birth; thus at puberty, the number of primary follicles is reduced to about 40,000
3) After puberty, atresia remains prevalent in all follicular stages
4) Typically about 400 follicles ovulate between puberty and menopause

Question 33

What type of tissue do atretic follicles form, how is this tissue cleared, and with what is it replaced?

Answer 33

Like the corpus albicans, atretic follicles also form scar tissue that is mostly removed by macrophages and restored as ovarian stroma by fibroblasts

Question 34

In secondary follicles, what surrounds the oocyte? What are these cells derived from?

Answer 34

1) In 2° follicles, multiple layers of granulosa cells surround the oocyte
2) Granulosa cells are derived by FSH-mediated proliferation of follicular cells, which transforms 1° follicles into 2° follicles

Question 35

In secondary follicles, what are the granulosa cells surrounded by? What do theca cells and granulosa cells secrete?

Answer 35

1) In 2° follicles, the granulosa cells are surrounded by several layers of stromal cell-derived theca cells (ignore theca interna)
2) Theca cells and granulosa cells secrete intermittent pools of follicular fluid, which contain growth factors and estrogen

Question 36

What transforms the secondary follicles into Graafian follicles? What is the corona radiata?

Answer 36

1) Coalescence of the follicular fluid pools creates an antrum that transforms 2⁰ follicles into Graafian follicles
2) The corona radiata (ignore cumulus oophorus) is a cluster of granulosa cells that surrounds the oocyte and protrudes into the lumen of the antrum

Question 37

What cells does FSH stimulate to release estrogen into the bloodstream? At the midpoint of the menstrual cycle, what do high estrogen blood levels lead to?

Answer 37

1) FSH also stimulates the granulosa cells and theca cells of 2° and mature follicles to release estrogen into the bloodstream
2) At the midpoint of the menstrual cycle, high estrogen blood levels stimulate LH release from the pituitary

Question 38

LH is essential for what process? Which Graafian follicle undergoes ovulation during each cycle? How does this contribute to the menstruation period?

Answer 38

1) LH is essential for ovulation
2) The Graafian follicle receiving the highest dose of LH undergoes ovulation
3) During each normal cycle, several Graafian follicles develop but only one ovulates at midcycle (day 14 of the typical 28-day menstrual cycle)

Question 39

What does LH transform the granulosa and theca cells into and what do these cells constitute? Under the influence of LH, what do luteal cells release into the bloodstream?

Answer 39

1) In the ovulated follicle, LH transforms both the granulosa cells and theca cells into luteal cells, which constitute the corpus luteum
2) Under the influence of LH, luteal cells release progesterone into the bloodstream

Question 40

Around day 25, what do high progesterone blood levels lead to? What causes degeneration of the corpus luteum and what is it converted to?

Answer 40

1) Around day 25, high progesterone blood levels inhibit LH release from the pituitary
2) Decreased levels of circulating LH cause degenerative transformation of the corpus luteum into the fibrous corpus albicans

Question 41

What provides continuity of the uterine lumen with the peritoneal cavity? During ovulation, what do fimbria do?

Answer 41

1) The open ends of the uterine tubes provide continuity of the uterine lumen with the peritoneal cavity
2) During ovulation, fimbria (finger-like projections from the end of the uterine tube) closely surround the ovary thereby expediting tubular uptake of the oocyte and corona radiata

Question 42

How long are the oviducts? What is noticeable of the mucosa in the ampullary portion of the oviducts? What do bundles of smooth muscle in the ampullary wall contribute to?

Answer 42

1) The oviducts are 12-15 cm long
2) There is extensive folding of the mucosa in the ampullary portion of the oviducts
3) The bundles of smooth muscle in the ampullary wall contribute to peristaltic movement of a fertilized oocyte (aka zygote) toward the uterus

Question 43

What types of cells does the epithelium of the ampullary portion of the uterine tubes contain? Define their respective functions.

Answer 43

1) The epithelium of the ampullary portion of the uterine tubes contains ciliated cells and secretory cells
2) Ciliated cells: The chief function of ciliary motility is transport of oocytes from upper to lower ends of fallopian tubes
3) Secretory (peg) cells: synthesize and secrete glycoproteins to provide nutrients to oocytes

Question 44

What is the frequency of tubal pregnancies and why can a ruptured tubal pregnancy be incorrectly diagnosed as acute appendicitis?

Answer 44

1) 1/250

2) The uterine tube is very close in proximity to the appendix in the lower right quadrant

Question 45

During ovulation, what do the oocyte and corona radiata pierce? What would result if the fimbriae of the uterine tube failed to enclose the ovary?

Answer 45

1) During ovulation, the oocyte and corona radiata pierce the broad ligamental covering of the ovary
2) If the fimbriae of the uterine tube fail to enclose the ovary, the ovulated cells could enter the peritoneal cavity

Question 46

What does the endometrium represent? What does the myometrium consist of?

Answer 46

1) The endometrium represents the uterine mucosa
2) The myometrium consists of multiple longitudinal and oblique layers of smooth muscle that occupy most of the uterine wall

Question 47

What is the most common tumor in the female pelvis and what is its primary symptom?

Answer 47

1) Leiomyomas, commonly known as fibroids, are benign tumors of the uterus that arise as localized hyperplasia of smooth muscle cells of the myometrium
2) A common symptom is excessive and prolonged bleeding at menstruation

Question 48

What is the probable pathogenesis of endometriosis?

Answer 48

Of unknown etiology, the disorder may result when endometrial cells peel off the uterine lining during the menstrual cycle and migrate via fallopian tubes to the peritoneal cavity

Question 49

Large blood vessels in the myometrium are branches of what artery? What supplies the basal layer and the larger endometrial functional layer?

Answer 49

1) Large blood vessels in the myometrium are branches of the uterine artery
2) The straight arteries supply the basal layer of the endometrium and the larger endometrial functional layer is supplied by the spiral arteries

Question 50

What do days 1-4 of the menstrual cycle represent? When does the proliferative phase start and what does it entail?

Answer 50

1) Days 1-4 of the menstrual cycle represent the menstrual phase of the cycle that results in shedding of the endometrial functional layer
2) The proliferative phase starts at day 5 when under the influence of estrogen, the unshed basal layer initiates restoration of the functional layer

Question 51

In the endometrial basal layer, what reforms the uterine glands? What is completed by day 14?

Answer 51

1) In the basal layer, invagination of the simple columnar epithelium reforms the uterine glands
2) Progressive elongation of the glands within the proliferating lamina propria is completed by day 14

Question 52

What does progesterone stimulate the endometrial glandular cells to secrete after ovulation? What does this result in for the glandular lumens?

Answer 52

1) After ovulation, corpus luteum-derived progesterone stimulates the endometrial glandular cells to secrete glycogen and glycoproteins into the glandular lumens
2) Thus, the lumens are progressively distended by the secretions and become sacculated

Question 53

What does progesterone induce in the spiral arteries and what does it result in? What does this allow for in the secretory phase of the cycle?

Answer 53

1) Progesterone induces vasodilation of the spiral arteries and the resulting increase in capillary blood flow creates mild edema in the lamina propria
2) Thus, during the secretory phase of the cycle, the functional layer is readied for potential zygote implantation

Question 54

Toward the end of the secretory phase, what do high progesterone blood levels inhibit? In the absence of zygote implantation, what does reduced LH lead to? What does a decrease in progesterone blood levels lead to? What does resulting ischemia induce?

Answer 54

1) Toward the end of the secretory phase, high progesterone blood levels inhibit LH release from the pituitary
2) In the absence of zygote implantation, reduced LH leads to a decrease in progesterone blood levels
3) This decrease results in vasoconstriction of the spiral arteries
4) The resulting ischemia induces shedding of the functional layer as menses

Question 55

Which pituitary and ovarian hormones induce the proliferative and secretory phases of the menstrual cycle and how do endometrial changes characterize each phase?

Answer 55

1) Proliferative phase:
a) FSH from the pituitary and estrogen from the ovaries (mainly from the growing follicles)
b) Immediately after the menstrual phase in which the entire functional endometrial layer is lost. The proliferative phase is there to reconstruct the functional layer of the endometrium. FSH produces estrogen, which is the growth factor that stimulates reconstruction of this layer.
2) Secretory phase:
a) LH from the pituitary gland and progesterone from the corpus luteum
b) During the secretory phase, the corpus luteum produces progesterone, which plays a vital role in making the endometrium receptive to implantation of the blastocyst and supportive of the early pregnancy, by increasing blood flow and uterine secretions and reducing the contractility of the smooth muscle in the uterus; it also has the side effect of raising the woman’s basal body temperature.

Question 56

Where does the cervix open into?

Answer 56

The cervix, the cylindrical end of the uterus, opens into the vagina (to be studied later)

Question 57

What is the appearance of the mucosa of the proximal cervix during the proliferative phase, secretory phase, and menstrual phase?

Answer 57

The mucosa of the proximal cervix (aka endocervix) resembles the endometrium at the end of the proliferative phase but realize it remains unaltered during the secretory and menstrual phases of the cycle

Question 58

What lines the exocervix and what is the exocervix?

Answer 58

Nonkeratinized stratified squamous epithelium lines the exocervix, the distal portion of the cervix that opens into the vagina

Question 59

Where is there an epithelial transformation in the cervix? Define the clinical relevance of this transformation zone of the cervix.

Answer 59

1) There is an epithelial transformation at the junction of the endocervix and exocervix
2) The transformation zone is subject to tumor formation and is the site of most cervical carcinomas

Question 60

What are nabothian cysts?

Answer 60

1) The endocervix is lined by mucus-secreting simple columnar epithelium that is arranged as deep compound furrows
2) The epithelium has glandular invaginations that are large and more branched than those in the body of the uterus and that secrete mucus
3) The glands sometimes become occluded and dilate, so follicles known as nabothian cysts form

Question 61

How does the incidence of squamous cell carcinoma and adenocarcinoma differ in the cervix?

Answer 61

Squamous cell carcinoma occurs 90%, adenocarcinoma 10%