chap 8.1

What are the two major gonadotropins?

FSH and LH

What hormone stimulates FSH and LH release?

GnRH

What hormone causes follicular growth?

FSH

What hormone is dominant during the follicular phase?

Estradiol

What ends the follicular phase?

Ovulation

Low levels of estradiol cause what type of feedback?

Negative feedback

High levels of estradiol cause what type of feedback?

Positive feedback

What is needed to activate the surge center?

High estradiol

What two conditions are required for the preovulatory surge?

High estradiol and low progesterone

What hormone is produced by small follicles to keep everything in check?

Inhibin

What is the main function of inhibin?

Suppresses FSH

Why is inhibin important?

Prevents premature ovulation.

What hormone surge directly causes ovulation?

LH surge

What hormone surge causes the LH surge?

GnRH surge

What does the tonic center release?

Basal pulses of GnRH

How often does the tonic center release GnRH?

Every 4-6 hours

Does the tonic center stop during the GnRH surge? y/n

No

What is a follicular wave?

group of follicles recruited and growing together

What is the sequence of follicular development?

Recruitment → Selection → Dominance → Ovulation/Atresia

What is the fate of follicles in the first wave?

Atresia

Why can't first-wave follicles ovulate?

High progesterone blocks the LH surge

What is the progesterone block?

Progesterone preventing ovulation and surge center activation

What are the two primary causes of atresia?

Decreased blood supply and decreased FSH

What is angiogenesis?

Formation of new blood vessels

What hormone causes luteolysis?

PGF₂α

Where is PGF₂α produced?

endometrium of a non-pregnant uterus

Why is estradiol both positive and negative feedback?

Low E2 = neg, high E2 = pos

Why can't follicles engage the surge center during diestrus?

Progesterone prevents enough estradiol production