Part 2: Menstruation

Question 1

Draw the menstrual cycle with all hormone levels:

Answer 1

Question 2

When do the lowest gonadotropin (LH/FSH) levels occur during the menstrual cycle?

Answer 2

mid-follicular phase.

Question 3

When do the highest gonadotropin (LH/FSH) levels occur during the menstrual cycle?

Answer 3

ovulation; with LH > FSH.

Question 4

Which gonadotropin (LH/FSH) is higher during the preovulatory surge?

Answer 4

FSH > LH; both increase.

Question 5

Which gonadotropin (LH/FSH) is higher during ovulation?

Answer 5

LH > FSH; both increase.

Question 6

What causes FSH levels to remain low throughout the follicular phase (2):

Answer 6

1. E2 negative feedback.
2. Inhibin B secreted from pre-ovulatory granulosa cells.

Question 7

What causes FSH levels to increase during the preovulatory surge (2)?

Answer 7

1. E2 positive feedback (switches).
2. Activin secreted from pre-ovulatory granulosa cells.

Question 8

Activin and inhibin; origin during the menstrual cycle and what they promote:

Answer 8

• Origin: pre-ovulatory granulosa cells.
  
  • Activin: promotes FSH secretion.
  • Inhibin: inhibits FSH secretion.

Question 9

During the luteal phase, FSH levels decrease due to (2):

Answer 9

1. Inhibin A secreted from granulosa-lutein cells.
2. Elevated progesterone and E2.

Question 10

Draw graph of FSH levels throughout the menstrual cycle and hormones inhibiting/promoting FSH expression:

Answer 10

Question 11

During the early-mid follicular phase, granulosa cells produce inhibin B. This causes (2):

Answer 11

1. decreased FSH secretion.
2. decreased FSH secretion leads to non-selected follicle atresia.

Question 12

The FSH surge during the pre-ovulatory phase leads to (3):

Answer 12

1. increased FSH-mediated E2 production in preovulatory granulosa cells.
2. increased LH receptor expression in preovulatory granulosa cells.
3. growth of young recruited follicles.

Question 13

What leads to the “luteinization” of preovulatory granulosa cells?

Answer 13

• Preovulatory FSH surge leads to increased LH receptor expression in preovulatory granulosa cells.

Question 14

Draw graph of LH levels throughout the menstrual cycle and hormones inhibiting/promoting LH expression:

Answer 14

Question 15

What hormone is responsible for ovulation?

Answer 15

• LH.
• LH causes pre-ovulatory follicle to extrude oocyte.

Question 16

Progesterone levels are low throughout a majority of the follicular phase. What causes their increase right before ovulation?

Answer 16

• granulosa cells becoming luteinized by increased FSH.

Question 17

Draw graph of Progesterone (P4) levels throughout the menstrual cycle.

Answer 17

Question 18

What hormone leads to an increase in basal body temperature by 0.5 degrees Fahrenheit during the luteal stage?

Answer 18

• Progesterone.
• Useful marker of ovulation.

Question 19

If the body temperature does not rise cyclically in a woman of reproductive age, what is this indicative of?

Answer 19

• body is not making progesterone.
• ovulation/corpus luteum formation is not occurring.

Question 20

Effect of sustained progestins on gonadotropins:

Answer 20

• Binds hypothalamic progestin receptors; alters GnRH pulse firing pattern
  
  • inhibits LH > FSH secretion.
  • blocks ovulation.

Question 21

Sources of sustained progesterone and their effects (3):

Answer 21

1. theca-lutein cells and granulosa-lutein cells.
2. placenta.
3. exogenous P4 contraceptives.

INHIBIT LH > FSH SECRETION;

BLOCKS OVULATION.

Question 22

Draw graph of estrogen levels during the menstrual cycle and source:

Answer 22

Question 23

The rise in estrogen during the pre-ovulatory follicular phase is attributable to:

Answer 23

• E2 secretion from granulosa cells in preovulatory follicle + younger growing follicles.

Question 24

The sustained elevated levels of E2 during the luteal phase is attributable to:

Answer 24

• corpus luteum granulosa-lutein cells.
  
  • only cells that contain CYP19; aromatase.

Question 25

Effect of sustained estrogens on gonadotropins:

Answer 25

* binds hypothalamic ERα receptors; alters GnRH pulse frequency. * inhibits FSH \> LH secretion.

Question 26

Sources of sustained estrogen and their effects (3):

Answer 26

1. pre-ovulatory granulosa cells. 2. corpus luteum granulosa-lutein and theca-lutein cells. 3. estrogen-based oral contraceptives. ## Footnote **INHIBITS FSH \> LH SECRETION.**

Question 27

Effect of sustained androgens (testosterone) on gonadotropins:

Answer 27

* converted to E2 via CYP19 (aromatase). * binds hypothalamic ERα receptors; alters GnRH pulse frequency. * inhibits FSH \> LH secretion.

Question 28

Sources of androgens/testosterone and their effects:

Answer 28

1. Theca cells (females). 2. Leydig cells (males). 3. Androgenic anabolic steroids. ## Footnote **INHIBITS FSH \> LH SECRETION.**

Question 29

Effect of prolactin on gonadotropin (LH/FSH) secretion:

Answer 29

inhibits LH/FSH secretion.

Question 30

What hormone is an inhibitor of prolactin secretion?

Answer 30

* dopamine.

Question 31

The effects of E2 and progesterone on gonadotropin secretion during the menstrual cycle at: 1. **early/mid-follicuar phase:** 2. **preovulatory phase:** 3. **ovulation:** 4. **luteal phase:**

Answer 31

1. **early/mid-follicuar phase:** (-) E2 feedback. 2. **preovulatory phase:** (+) E2 positive feedback. 3. **ovulation:** (+) E2 positive feedback. 4. **luteal phase:** (-) E2 + P4 feedback.

Question 32

Follicular phase defects will disrupt (3):

Answer 32

1. folliculogenesis. 2. oocyte maturation. 3. ovulation.

Question 33

Luteal phase defects will disrupt (3):

Answer 33

1. implantation. 2. pregnancy. 3. feedback necessary for next menstrual cycle.

Question 34

The combination of what three factors disrupts GnRH pulsatility and decreases both FSH and LH during the luteal phase?

Answer 34

E2, P4, inhibin A

Question 35

What occurs to the oocyte after ovulation?

Answer 35

* completes meiosis I; awaits fertilization.

Question 36

What occurs to the remnant of what was the selected preovulatory follicle following ovulation?

Answer 36

* stimulated by LH to terminally differentiate into the corpus luteum.

Question 37

The rise of what hormone level indicates that ovulation has occurred?

Answer 37

* progesterone; also 0.5 degree F body temperature rise.

Question 38

Following ovulation, corpus luteum granulosa-lutein cells and Theca-lutein cells begin secreting large amounts of progesterone and some estrogen. Secretion is driven by which gonadotropin?

Answer 38

LH

Question 39

Effects of progesterone and E2 on the endometrium during the luteal phase:

Answer 39

* proliferative and angiogenic effects. * prepares for implantation.

Question 40

Effects of progesterone on the myometrium:

Answer 40

* prevents myometrium contraction.

Question 41

During the pre-ovulatory proliferative/follicular phase, rising E2 causes what changes to the endometrium (3)?

Answer 41

1. increase in ERα and P4-R expression. 2. increase in growth factors. 3. proliferation and angiogenesis.

Question 42

Effect of high progesterone levels on the endometrium during the secretory/luteal phase:

Answer 42

* negative feedback on ERα and P4-R expression. * prepares endometrium for menstruation and endometrial shedding.

Question 43

Menstruation/endometrial shedding results from:

Answer 43

* drop in progesterone and E2 levels. * occurs during late luteal phase.