Female Reproductive Physiology and Histology

Question 1

What happens during the follicular (proliferative) ovarian phase?

Answer 1

LH and FSH promote follicle growth and differentiation

Ovulation happens when sudden surge in estradiol = LH & FSH surge

Question 2

What happens during the luteal (secretory) ovarian phase?

Answer 2

Follicle differentiates into corpus luteum which then secretes progesterone and estradiol
- if no pregnancy = luteolysis

Question 3

What is the proliferative phase of the endometrial cycle?

Answer 3

ESTRADIOL promotes the PROLIFERATION of the endometrium

- concurrent with follicular phase of ovarian cycle

Question 4

What is the secretory phase of the endometrial cycle?

Answer 4

PROGESTERONE promotes DIFFERENTIATION of endometrium

- concurrent with luteal phase

Question 5

What is menses?

Answer 5

Coincides with luteal regression

No corpus luteum = progesterone levels decline = endometrium sheds because progesterone isn’t there to maintain it

Question 6

What is the main steroid secreted during the follicular phase? During luteal phase? What secretes them?

Answer 6

Follicular phase: estradiol secreted by growing follicle

Luteal phase: progesterone secreted by corpus luteum

Question 7

What are primordial follicles?

Answer 7

Primary oocytes surrounded by a single layer of granulosa cells

Question 8

Granulosa cells respond to what hormone to make what?

Answer 8

FSH to make estradiol

Question 9

Theca cells respond to what hormone to make what?

Answer 9

LH to make androgens (ex: progesterone)

Question 10

How many follicular cell types are needed to make estradiol? What is that reaction?

Answer 10

2 cell types

androstenedione (theca cells) converted to estradiol (granula cells) through aromatase (irreversible reaction)

Question 11

What is luteinization and what hormones does this process involve?

Answer 11

Ovarian follicle becoming corpus luteum

Involves both granulosa and theca cells

Question 12

Main hormone acting on corpus luteum (on luteal cells)

Answer 12

LH

Question 13

What cells produce inhibin B? Function of Inhibin B?

Answer 13

Produced by granulosa cells during the early stages of follicular development in response to increasing estradiol secretion from the dominant follicle
- suppresses FSH secretion (along with estradiol) during the selection of the dominant follicle (starve off the non-dominant follicles)

Question 14

What proteins do estradiol and progesterone bind to in blood?

Answer 14

Estradiol: SHBG
Progesterone: albumin (80%), CBG (cortisol binding globulin)

Question 15

Function and production of Inhibin A

Answer 15

Produced by luteal cells (corpus luteum); also has a negative feedback on FSH but allows FSH to accumulate in the pituitary

Question 16

Describe GnRH/LSH pulse during follicular and luteal phase

Answer 16

Follicular: low amplitude; increase in frequency closer to ovulation
Luteal: infrequent, high amplitude

Question 17

2 negative feedback mechanisms that happen during follicular phase

Answer 17

1. estradiol on GnRH through KNDy neurons; also direct negative feedback on FSH and LH
2. Inhibin B: FSH

Question 18

Negative feedback mechanisms during luteal phase

Answer 18

1. progesterone: on GnRH through KNDy neurons

2. Inhibin A: FSH

Question 19

Describe the LH/FSH levels (high or low) during the following periods and why:

1. after birth until puberty
2. during puberty
3. during pregnancy
4. during gestation
5. menopause

Answer 19

1. low because GnRH secretion is low
2. diurnal pattern (high at night)
3. low because of high progesterone and estradiol levels (which have a negative feedback)
4. high
5. high because ovarian follicles and oocytes have been depleted = decreased inhibins and estradiol = no negative feedback effect

Question 20

What 2 hormones can you measure to measure ovarian reserve?

Answer 20

Inhibin B and antimullerian hormone (AMH) – levels will be low if few follicles

Question 21

Why does increased body fat stimulate GnRH secretion

Answer 21

Because of increased leptin synthesis

Question 22

What is PTEN?

Answer 22

Lipid phosphatase that reverses the PI3 kinase reaction and maintains primordial follicles in an inactive state

Question 23

What does it mean by granulosa and theca cell hyperplasia?

Answer 23

Exponential increase in these cells from the primordial follicle to the preovulatory follicle