7 - Follicular Phase Flashcards
Six primary events of the follicular phase
- Elevated gonadotropin release (FSH & LH)
- Follicle growth & prep for ovulation
- Increase and peak in E2
- Sexual receptivity (estrus)
- LH surge
- Ovulation
Slide 6
The important diagram
Four processes of ovarian follicular development
- Recruitment
- Selection
- Dominance
- Atresia
What is recruitment
Small follicles begin to grow & produce E2
FSH is dominant hormone
What is selection
Selected follicle(s) proceed towards dominance (rest become atretic)
FSH + moderate LH & E2
What determines which follicles are recruited and which become atretic
Amount of receptors the follicle has for FSH (more = selected)
What is dominance
Dominant follicle(s) proceed to the point of ovulation & inhibit other follicles
LH & E2 + Inhibin
What is atresia
Degeneration & resorption of follicles that did not develop prior to ovulation
Slide 9-12
Follicular development diagrams ***
What are the roles of FSH and LH in follicular dynamics
There are stages dependent on each hormone
FSH dependent = recruited & early selected follicles
LH dependent = large selected & preovulatory follicles
What follicles become preovulatory?
Those with more LH receptors
Slides 14-16
Real follicles at different stages **
How many waves of follicular development are there?
Several occur during the Estrous cycle
What determines if a wave of follicular development reaches ovulation or not
Waves that occur during metestrus &/or diestrus (with high progesterone) will not reach ovulation; will be atretic & regress
Wave initiated during proestrus will develop into estrus stage and reach ovulation
Slide 18
Estrogen vs estradiol
Estrogen = substance (natural or synthetic) that exerts biological activity having an estrogenic effect (e.g. Estradiol, Estriol)
Estradiol = predominant estrogen produced by ovarian follicles during the estrous cycle
