Normal menstrual cycle

Question 1

What is the main function of the ovaries?

Answer 1

Produce mature ovum in each cycle and to prepare genital tract for fertilization and implantation of that ovum for propagation

Question 2

What is the menstrual cycle?

Answer 2

A highly regulated physiological process in which the coordinated release of hormones from the hypothalamus, pituitary gland, and ovaries produces a mature oocyte and prepares the endometrium for blastocyst implantation.

Question 3

How long is an average cycle?

Answer 3

21-35 days

Question 3

Which 2 cycles make up the menstrual cycle?

Answer 3

Ovarian and Uterine cycles

Question 4

Name the 3 phases of the ovarian cycle.

Answer 4

Follicular phase (day 1-14), Ovulation (day 14) and Luteal phase (for 14 after ovulation)

Question 4

Name the 3 phases of the uterine cycle.

Answer 4

Menstrual phase (day 1-5,6,7), Proliferative phase (day 5- 14) and Secretory phase (day 14-28)

Question 4

Which hormones are produced during the follicular phase?

Answer 4

Hypothalamus releases gonadotropin-releasing hormone (GnRH) in pulses, stimulating the anterior pituitary gland to release follicle-stimulating hormone (FSH) and luteinizing hormone (LH).

Question 4

What is the function of FSH and LH during the follicular phase?

Answer 4

Stimulate the growth of antral follicles

Question 5

What is the function of FSH alone during the follicular phase?

Answer 5

Stimulation of granulosa cells which produce estradiol and inhibin

Question 6

What is the function of LH alone during the follicular phase?

Answer 6

Stimulates ovarian theca cells and induces the production of progesterone and androstenedione

Question 7

What decrease in FSH in follicular phase lead to?

Answer 7

Regression of all follicles except one

Question 8

What happens during ovulation?

Answer 8

LH surge induces release of mature oocyte from dominant follicle

Question 9

What does the ruptured follicle transform into during the luteal phase?

Answer 9

Corpus luteum

Question 10

What does the corpus luteum produce?

Answer 10

Progesterone and estradiol (inhibit gonadotropin release, negative feedback)

Question 11

What happens to the corpus luteum in the absence of fertilization?

Answer 11

It degenerates

Question 12

What does decrease in progesterone and estradiol levels induce?

Answer 12

Vasospasms and ischemia in uterine spiral arteries and apoptosis of functional layer of endometrium leading to shedding of the endometrial lining

Question 13

Mention 4 processes that take place during the proliferative phase.

Answer 13

1. Uterine spiral arteries regenerate & extend 2/3 of the way into endometrium
2. Stromal cells divide, enlarge, and accumulate glycogen
3. Endometrial glands become straight, tubular, & lined by simple columnar epithelium.
4. Endometrial epithelial cells proliferate

Question 13

What is the function of progesterone produced by the corpus luteum during the secretory phase?

Answer 13

Promotes endometrial differentiation & other changes that prepare the body for blastocyst implantation.

Question 13

Define amenorrhea.

Answer 13

The absence of menstruation. Classified as primary (no menarche by 15 years of age) or secondary (absence of menstruation for more than 3–6 months in an individual who previously menstruated).

Question 13

What happens to the following structures during the secretory phase:
a) Stromal cells
b) Uterine spiral arteries
c) Endometrial glands

Answer 13

a) Become edematous
b) Extend fully into endometrium
c) Increase tortuosity & produce glycogen-rich secretions

Question 13

Define primary dysmenorrhea.

Answer 13

Recurrent lower abdominal pain shortly before or during menstruation (in the absence of pathologic findings that could account for those symptoms)

Question 13

Define secondary dysmenorrhea.

Answer 13

Recurrent lower abdominal pain shortly before or during menstruation that is due to an underlying condition

Question 14

Describe the hypothalamic-pituitary axis.

Answer 14

In the hypothalamus, GnRH is released and it is transported to the anterior pituitary gland where it activates G protein-coupled receptors thereby signaling the gland to release FSH and LH both of which then travel to the ovaries via the bloodstream to stimulate production of sex steroid hormones from the follicular cells.

Question 15

Name the 2 types of cells in the ovarian follicle and what they release.

Answer 15

Theca cells are stimulated by LH to produce progesterone and androstenedione

Granulosa cells are stimulated by FSH, specifically the enzyme aromatase in granulosa cells which then converts androstenedione to testosterone and then to 17-B estradiol

Question 16

What would the ovum release if it was fertilized?

Answer 16

Human Chorionic Gonadotrophic hormone thus stimulating the corpus luteum to maintain progesterone production

Question 17

What are anovulatory cycles?

Answer 17

This is when ovulation does not occur at the end of the follicular phase so one does not get menses.