Follicular Phase Flashcards
What majorevents ave occurring in the follicular phase?
GnRH is elevated, follicles are growing, sexual receptivity, ovulation
What hormone dominates this phase?
E2
In low concentrations of e2, what happens to the surge center?
It is suppressed by a negative feedback
In high concentrations of E2, what happens to the surge Center?
It is stimulated
What marks the beginning of this phase?
Luteolysis and the decline in P4
What is produced by the Antral follicle that stops FSH?
Inhibin
What structures controls the start of the new cycle?
Hypothalamus, adenohyphosis, ovaries
What stimulates secretion of FSH/LH from the AP so they can stimulate E2 from follicles?
An increase in GnRH frequency
What are the four steps in Follicle dynamics?
Recruitment, selection, dominance, atresia 
Recruitment of follicles occurs during which phase?
Metestrus
Which hormone during selection decreases while the other increases?
FSH decreases while LH starts going up
In dominance, something causes positive feedback which means there’s no corpus luteum, what is that something?
Follicle with an antrum which increases estradiol 
What are the two main reasons that a atresia occurs in the almost 90% of the follicles?
Because the follicle has a lack of blood supply or it lacks LH receptors
During the metestrus and diestrus, LH is pulsing around six times per day what is it stimulating primarily?
Final growth and then ovulation
What structure changes the feedback loop?
The preovulatory follicle
What is specific to cattle in terms of follicular dynamics?
Cattle have follicular waves where they recruit follicles select them but they undergo atresia
Why did the follicles during bovine follicular waves undergo atresia?
Because progesterone is too high and they cannot ovulate because estradiol is inhibited
During which phase does LH increase frequency to every hour to prime the brain?
Proestrus
In a dominant follicle where is the LH receptor located?
Theca interna
In a dominant follicle where is the FSH receptor located?
Granulosa
LH stimulates CAMP and protein kinase which mixes with cholesterol to produce what?
Testosterone
Where does testosterone go to get mixed with protein kinase to get converted into what?
Testosterone goes to granulosa cells mixes with protein kinase and it’s converted into estradiol
In granulosa cells there are luteal cells produced primarily what?
Steroids (estrogen)
What two things does L H drive?
The conversion of cholesterol to testosterone and estrogen levels increasing
What is the primary target of estradiol?
The reproductive tract
What does estradiol cause in organs?
Hyperemia
What does the Follicle do in preparation for ovulation?
Synthesizes the new LH receptors by granulosa
When LH surge is right before ovulation, what do the a interna cells produce instead of testosterone?
Progesterone
When progesterone is stimulated by the a interna cells what does stimulate?
Collagenase to increase pressure of the antrum
What other two hormones are secreted locally and act locally on the follicle?
PGE2 (remodeling) and PF2α (lysosomal enzymes)
What is the term when more tests than are needed are released by using GnRH to increase FSH?
Superovulation
