Female Reproductive System

Question 1

What is the outermost layer of the ovary?

Answer 1

Germinal epithelium (modified peritoneal layer) that is mostly cuboidal epithelium.

Question 2

What is the thick connective tissue layer that surrounds the parenchyma of the ovary called?

Answer 2

The entire ovary is encased within a connective tissue capsule called the tunica albuginea.

Question 3

Where in the ovary would you find the various stages of the female gamete?

Answer 3

The cortex of the ovary is the site of generation of the female gamete or ovum (including developing follicles [oocyte + supportive cells] and surrounding stromal cells.

Question 4

In what phase of replication are primary oocytes arrested?

Answer 4

Primary oocytes are arrested in prophase of meiosis I until puberty or beyond.

Question 5

What surrounds the oocyte when it is in a primary follicle?

Answer 5

The oocyte secretes the constituents of the zona pellucida which surrounds it until well after fertilization.

Question 6

What is the difference in appearance between a primordial and a primary follicle?

Answer 6

The primordial follicle is surrounded by flattened, squamous-appearing epithelial cells and no evident zona pellucidum. In the primary follicle, there is a prominent zona pellucidum and a single layer of cuboidal granulosa cells.

Question 7

What hormone stimulates a cohort of primary follicles to mature?

Answer 7

The further development of a cohort of preantral follicles will be stimulated each month by follicle stimulating hormone (FSH) and secondary (antral) follicles will be formed.

Question 8

What is the main product of the granulosa cells of the antral follicle and what causes them to produce this?

Answer 8

With stimulation by both FSH and luteinizing hormone (LH), the granulosa cells, working together with a population of modified stromal cells, the theca interna, will begin producing estrogens.

Question 9

What is the appearance of the Graafian follicle?

Answer 9

The fully mature, Graafian follicle is characterized by a large antrum filled with the liquor folliculi, and containing an oocyte within a collection of granulosa cells, the cumulus oophorus. The granulosa cells surrounding the oocyte are the corona radiata.

Question 10

What is the main trigger for the “LH surge”?

Answer 10

Increasing levels of estrogen result in an LH surge which then triggers the completion of meiosis I and the process of ovulation. Typically only one of the cohort of antral follicles will be ovulated,

Question 11

What happens to the other Graafian follicles that have matured but not ovulated during the cycle?

Answer 11

The remainder of the follicles will undergo degeneration into atretic follicles (corpora fibrosa).

Question 12

What happens to the follicle immediately after ovulation?

Answer 12

Following ovulation, the remnant of the follicle will be converted into a corpus luteum (CL). This has two components, a granulosa lutein and a theca lutein. Residual LH will stimulate these cells to produce progesterone (and some estrogen).

Question 13

What happens to the corpus luteum if fertilization does not take place?

Answer 13

In the absence of pregnancy, the corpus luteum will degenerate into a corpus albicans and the ovarian cycle will begin again.

Question 14

What is the main stimulus for the proliferative phase of the endometrium?

Answer 14

Estrogen from the maturing follicles stimulates the proliferative phase of the endometrial cycle.

Question 15

What happens to the endometrium during the proliferative phase of the menstrual cycle?

Answer 15

During the proliferative phase of the endometrium, endometrial tissues, both epithelial tissues and stromal cells, are mitotically active. This results in the development of a thick stratum functionalis layer from the underlying stratum basalis.

Question 16

What is the main stimulus for the secretory phase of the endometrium?

Answer 16

Progesterone from the corpus luteum leads to the secretory phase.

Question 17

What happens during the secretory phase of the endometrium?

Answer 17

The endometrial glands begin production of glycogen-rich secretions in anticipation of nourishing an implanted embryo.

Question 18

What triggers menstruation?

Answer 18

The corpus luteum stops producing hormones and this decline causes the spiral arteries to contract, cutting off blood supply to the functional layer of the endometrium

Question 19

At what stage is the oocyte at the time of ovulation?

Answer 19

Ovulation marks the completion of meiosis I and the formation of a secondary oocyte (i.e., becomes haploid).

Question 20

What happens to the cell cycle of the secondary oocyte?

Answer 20

It arrests in the metaphase of Meiosis II and will only finish this if it is fertilized.

Question 21

How is the oocyte moved through the uterine tube?

Answer 21

Both ciliary action and peristaltic waves generated by the smooth muscle layers of the oviduct help propel the egg through the isthmus, into the intramural portion of the oviduct and finally into the uterine cavity. The mucosa of the oviduct, especially the distal end, is thrown into numerous folds, and is covered by a ciliated, simple columnar epithelium that sweep toward the uterine cavity. At the time of ovulation, the secondary oocyte is usually swept into the fimbriated end or infundibulum of the oviduct and then into its ampulla.

Question 22

What is the function of “peg” cells?

Answer 22

Secretory cell that produces glycoproteins and nutritive components to nourish the oocyte as it travels through the uterine tube

Question 23

Where does fertilization usually take place?

Answer 23

Fertilization usually occurs in the distal segment of the oviduct when a spermatozoon penetrates the protective layer of granulosa cells and then enzymatically digests its way through the zona pellucida (the function of acrosomal enzymes). This allows for the fusion of the egg and sperm membranes.

Question 24

What prevents polyspermia?

Answer 24

Penetration of the oocyte by the sperm triggers a calcium flux in the oocyte resulting in discharge of cortical granules, producing a block to polyspermy.

Question 25

When does implantation of the blastocyst usually take place?

Answer 25

Implantation of the blastocyst into the endometrium usually occurs by day 7 (post-fertilization).

Question 26

Where is the most common location of ectopic implantation?

Answer 26

Ectopic implantation most commonly occurs in the oviduct (tubal pregnancy).

Question 27

What cells of the blastocyst invade the endometrium?

Answer 27

The syncytiotrophoblast layer leads invasion of the endometrium by the blastocyst

Question 28

What cells produce hCG and why is it important?

Answer 28

The production of human chorionic gonadotropin (hCG) by the syncytiotrophoblast is essential to the survival of the implanted embryo. This hormone provides continued stimulation of the corpus luteum (now a CL of pregnancy), and thus continued maintenance of the endometrium (now called the decidua). In subsequent weeks, the placenta will also become an important source of other hormones (e.g. estrogen, progesterone) necessary for normal gestation.

Question 29

What is the histologic structure of the cervix?

Answer 29

The uterine cervix is characterized by a dense fibromuscular stroma that maintains the narrow opening of the cervix and prevents fetal loss until it is softened late in pregnancy by the action of hormones. There is also a secretory mucosal layer responsible for the production of cervical mucus, the consistency of which changes during the menstrual cycle. The simple columnar epithelium of the endocervix gives way to a stratified squamous epithelium where the ectocervix is exposed to the vaginal environment.

Question 30

What is important about the site of transition from simple columnar to stratified squamous epithelium in the cervix?

Answer 30

The transformation zone where metaplasia occurs is the common site of development of cervical cancer, but dysplastic or neoplastic cell growth at this site can be readily monitored by means of Pap smears.

Question 31

What kind of epithelium lines the vagina?

Answer 31

The vagina is lined by a stratified squamous non-keratinized epithelium. The cells of the lining show changes during the monthly cycle, most notably in the quantity of glycogen produced by the cells.

Question 32

Are there any glands in the vagina?

Answer 32

NO GLANDS

Question 33

What comprises the remainder of the walls of the vagina?

Answer 33

The walls of the vagina are supported by a well-vascularized fibroelastic connective tissue, smooth muscle, and, at some levels, skeletal muscle from the urogenital diaphragm.

Question 34

What comprises the histologic structure of the labia majora and minora?

Answer 34

The vulva includes the labia majora and labia minora, both folds of skin containing sebaceous and sweat glands. The hair follicles and adipose tissue of the labia majora are not found in the labia minora.

Question 35

What is the histologic structure of the clitoris?

Answer 35

The clitoris represents a body of erectile tissue, comprised of a network of large, endothelial-lined sinuses supported by a network of fibromuscular trabeculae and surrounded by a thick connective tissue capsule (the tunica albuginia).