Follicular Physiology

Question 1

What are the 4 major events during the follicular phase?

Answer 1

Rising gonadotropin release from anterior pituitary
Follicle growth
Sexual receptivity
Ovulation

Question 2

What is the dominant hormone during the follicular phase?

Answer 2

Estrogen

Question 3

What role does the tonic center play in the follicular phase?

Answer 3

Small pulses of GnRH stimulates release of FSH and LH

Question 4

What role does the surge center play in the follicular phase?

Answer 4

Increasing levels of estrogen lead to release of a large quantity of GnRH which causes release of LH resulting in ovulation.

Question 5

What hormone does the dominant follicle release to ensure it’s the main event?

Answer 5

Inhibin

Question 6

What hormone does inhibin have a negative effect on?

Answer 6

FSH to make sure not other follicles are being stimulated

Question 7

What hormone does the dominant follicle release to give positive feedback to the hypothalamus causing a turnover to the surge center?

Answer 7

Estradiol

Question 8

What does the release of estradiol from the dominant follicle cause?

Answer 8

Preovulatory LH surge from the surge center

Question 9

During what phase of estrous cycle does FSH peak?

Answer 9

Estrus

Question 10

During what phase of estrous cycle does Progesterone peak?

Answer 10

Diestrus

Question 11

During what phase of estrous cycle does Estrogen peak?

Answer 11

Estrus

Question 12

During what phase of estrous cycle does LH peak?

Answer 12

Estrus

Question 13

What are the 4 parts of follicular dynamics?

Answer 13

Recruitment
Selection
Dominance
Atresia

Question 14

What is Recruitment?

Answer 14

Recruitment of small antral follicles

Question 15

What is Selection?

Answer 15

Follicles selected from recruited follicles

Question 16

What is Dominance?

Answer 16

Selected follicles that do not undergo atresia

NOTE: These follicles undergo ovulation.

Question 17

What is Atresia?

Answer 17

Follcles that do not proceed to dominance.

Question 18

On palpation, what would a dominant follicle feel like?

Answer 18

Feels like a blister.

Question 19

On palpation, what would a CL feel like?

Answer 19

A bump on the ovary.

Question 20

How do we cause superovulation for embryo transplant?

Answer 20

During the second wave or follicular dynamics (in diestrus) give lots of GnRH to cause a release of LH to lyse the CL and allow more follicles to develop and ovulate.

Question 21

What are the general levels of the 4 major hormones during recruitment?

Answer 21

High FSH
Low LH
No inhibin
No E2

Question 22

What are the general levels of the 3 major hormones during selection?

Answer 22

Low FSH
Moderate LH
Low inhibin

Question 23

What are the general levels of the 3 major hormones during dominance?

Answer 23

Low FSH
High LH
High inhibin

Question 24

Where does the estrogen come from?

Answer 24

LH binds to theca interna cells, producing testosterone which goes into the granulosa cells. When FSH binds to the granulosa cells, they convert testosterone to estrogen.

Question 25

How does the LH surge help get the oocyte to a place where it can be fertilized?

Answer 25

Meiosis inhibition is removed and the 4N oocyte is allowed to become 2N. At ovulation, a second meiotic division brings it to a 1N and the oocyte is now ready to be fertilized.

Question 26

What is strange about ovulation in dogs?

Answer 26

They ovulate a primary oocyte (4N).