Follicular Phase

Question 1

What are the two subphases of the follicular phase?

Answer 1

proestrus and estrus

Question 2

What are the concentration trends of the major hormones (P4, E2, LH, and FSH) during proestrus?

Answer 2

P4 plummets and reaches its lowest concentration, E2, LH, and FSH all start to rise

Question 3

What are the concentration trends of the major hormones (P4, E2, LH, and FSH) during estrus?

Answer 3

E2, LH, and FSH reach their peaks, P4 is at its lowest point

Question 4

Which of the four major hormones is most responsible for estrus, especially the physically manifestations of estrus?

Answer 4

the peak of E2, LH, and FSH

Question 5

What is the source of E2?

Answer 5

follicle

Question 6

What is the source of P4?

Answer 6

the corpus luteum

Question 7

What is the source of LH and FSH?

Answer 7

anterior pituitary

Question 8

What are follicular waves?

Answer 8

waves of maturation for follicular development

Question 9

What are follicular cohorts?

Answer 9

a group of follicles that are physically grouped together for follicular development

Question 10

What is super ovulation?

Answer 10

the process in which the ovary is pharmacologically nudged to ovulate more than 1 ovum

Question 11

What are cystic ovaries?

Answer 11

a pathological situation in which the follicles fails to ovulate

Question 12

What are the changes to the ovary that accompany the follicular phase?

Answer 12

a group of follicles are physically grouped and mature into small follicles, a portion of them undergo atresia while another portion matures into medium follicles, a small number of the medium follicles mature into large follicles, one of the large follicles is dominant. as the follicle develops a fluid filled sac enlarges and encompasses the ovum and once it is completely surrounded it is released from the ovary

Question 13

What is the relationship between LH and theca and granulosa cells?

Answer 13

LH activates receptors on these cells and stimulates the synthesis of testosterone in theca cells

Question 14

What is FSH’s role in production of estrogen?

Answer 14

it activates aromatase which converts testosterone into estrogen

Question 15

Why are there differing amounts of LH and FSH present during the follicular phase even though the release of both is equally stimulated by GnRH?

Answer 15

FSH is required for the recruitment of follicles, once that is complete, the release of FSH is inhibited. LH is required for the maturity of follicles so its release continues even though FSH has been inhibited

Question 16

What are the seven feedback mechanisms occuring during the follicular phase?

Answer 16

1) P4 prevents GnRH release (not depicted) at the hypothalamus
2) GnRH promotes LH and FSH release at the AP.
3) LH and FSH promote E2 synthesis in the follicle
4) E2 promotes GnRH release from the hypothalamus.
5) E2 promotes its own synthesis at the follicle (granulosa cell).
6) Inhibin prevents FSH release from the AP.
7) E2 promotes the LH surge from the AP (not depicted) at ovulation.