Regulation of the Female Reproductive Cycle

Question 1

What stimulates GnRH release in the brain?

Answer 1

NE

Question 2

What inhibits GnRH release in the brain?

Answer 2

DOPA

Question 3

What are the cellular actions of GnRH?

Answer 3

1. GnRH acts via a GPCR and increases Ca which causes FSH/LH release
2. GnRH action via DAG will increase FSH and LH synthesis

Question 4

What is the function of follistatin?

Answer 4

It binds activin which will reduce its concentration and result in the inhibition of of the pituitary for GnRH

Question 5

What is the effect of the drug Clomiphene?

Answer 5

It is a fertility drug that acts as an E2 receptor antagonist as with decreased E2 binding there will be less negative feedback and the GnRH pulse will increase as a result

Question 6

What occurs in the follicular phase?

Answer 6

Time of follicle growth that occurs from menses onto ovulation

Question 7

What is the hormone control in the follicular phase?

Answer 7

GnRH ->
FSH/LH release ->
E2 release ->
Follicle development

Question 8

What is the feedback found in the follicular phase?

Answer 8

E2 and inhibit have negative feedback on the hypothalamus and the pituitary that will keep GnRH volume down

Question 9

What makes Inhibin A?

Answer 9

Corpus Luteum

Question 10

What makes Inhibin B?

Answer 10

Dominant Follicle

Question 11

What occurs in the ovulatory phase?

Answer 11

It occurs over 1-3 days and the final oocyte maturation and release occurs

Question 12

What is the hormonal control in the ovulatory phase?

Answer 12

E2 levels reach a threshold and positive feedback will occur that causes an LH surge leading into ovulation

Question 13

What is the feedback found in the ovulatory phase?

Answer 13

Follicle rupture causes a decrease in E2 and loss of E2 positive feedback that occurs up to ovulation. This leads to a decrease in LH.

Question 14

What happens to the follicle after ovulation?

Answer 14

It reorganizes into the corpus luteum

Question 15

What occurs in the luteal phase?

Answer 15

Corpus luteum forms and hormones that promote implantation are released

Question 16

What hormones are released in the luteal phase?

Answer 16

The corpus luteum is dominant and so E2 and progesterone are released

Question 17

What is the feedback in the luteal phase?

Answer 17

Progesterone has strong negative feedback and E2 becomes inhibitory leading to decreased GnRH, LH and FSH

Question 18

What happens to the corpus luteum at the end of the luteal phase?

Answer 18

It will degrade without LH due to the decreasing LH unless it is rescued by hCG

Question 19

What is the process occurring with menses?

Answer 19

E2/progesterone are low after the luteal phase with the loss of the corpus luteum and FSH increases without negative feedback leading to endometrial sloughing

Question 20

What is required for the development of primordial follicles into primary follicles?

Answer 20

FSH/LH and appropriate E2 levels

Question 21

How are secondary follicles developed from primary follicles?

Answer 21

To make this follicle type, the theca cells proliferate and develop LH receptors.

Granulosa cells acquire receptors for FSH, androgens and estrogens.

Question 22

What is the inhibitory function of the dominant follicle?

Answer 22

Inhibits growth of other follicles, even those in the other ovary

Question 23

What are the other functions of the dominant follicle?

Answer 23

Alter cervical mucus to enhance sperm transport

Change fallopian tubes to enhance sperm transport

Question 24

What is the Two Compartment Theory of Graafian Follicle Steroidogenesis?

Answer 24

The theca and granulosa cells cooperate

Question 25

What is the role of the granulosa cells in the two compartment theory?

Answer 25

They have high aromatase with FSH stimulation and also produce progesterone and pregnenolone.

They cannot convert 21-C precursors into androgens very well

Question 26

What is the role of theca cells in the two compartment theory?

Answer 26

With LH stimulation they produce androgens and transport them to the granulosa

Question 27

What is the vascularization of the theca/granulosa cells?

Answer 27

The theca is well vascularized and has better access to circulating cholesterol

Question 28

What is the overall pathway of the Two Compartment Theory?

Answer 28

The theca takes cholesterol from the circulation and forms androgens. The androgens are then passed to the granulosa cells which are rich in aromatase and convert them into E2

Question 29

What are the phases of menstruation as described in terms of endometrial functions?

Answer 29

Proliferative
Secretory
Menstrual

Question 30

What occurs in the proliferative phase and what is the dominant hormone?

Answer 30

E2 is dominant. In the mid to late follicular phase the endothelium thickens with spiral artery development and increased progesterone and estrogen receptors.

Question 31

What occurs in the secretory phase and what is the dominant hormone?

Answer 31

Progesterone is dominant. Occurs during ovulation to late luteal phase and it shows increased vascularization and mucus secretion that is rich in carbohydrates.

Question 32

What occurs in the menstrual phase and what is the dominant hormone?

Answer 32

E2 and Progesterone are both low. Restriction of the spiral arteries leads to ischemia and necrosis with the rupture of blood vessels and infiltration of leukocytes.

Question 33

What is Spinnbarkeit and what is it indicative of?

Answer 33

It is stretchable mucus that indicates ovulation

Question 34

What is menopause?

Answer 34

It is the loss of negative feedback from E2 and inhibit that causes an increase in FSH/LH with FSH>LH which is different from the normal ratios.

Question 35

What are some of the consequences of menopause?

Answer 35

Osteoporosis
CV Disease
Decreased breast mass
Hot flashes

Question 36

What was found to be the effects of hormone replacement therapy in menopausal women?

Answer 36

Only shown to be beneficial for osteoporosis and most beneficial if used immediately at menopause rather than some time after.