Endocrine Control Flashcards
What does surge center stimulate?
Anterior pituitary which releases LH and FSH
What does LH influence?
Theca cells which releases testosterone
How does Estradiol effect the surge center?
Has positive feedback on surge center which stimulates anterior pituitary to release LH and FSH which causes for ovary to increase release of Estradiol
Role of inhibin?
Inhibin is produced by the granulosa cells of the dominant follicle, inhibin has negative impact on FSH which decreases the ability of small follicles to grow.
What role does estradiol play with FSH?
Inhibits FSH
What cells are responsible for secretion of estradiol?
Follicles
When do follicles begin to secrete inhibin?
At selection stage of follicle
Explain the effect of LH surge
- Increase in PGE2 which increases blood flow to ovary and dominant follicle
- Increase blood flow to o. and df causes edema which increases follicular pressure
- Increase PGF2alpha which increases Contraction of ovarian smooth muscle (increase follicular pressure) as well as release of lysosomal enzymes (weakens follicle wall0
- Shift from E2 to P4 which increases collagenase (weakens follicle wall)
- Gap junction breakdown between granulosal cells and oocyte
4 examples of induced ovulators
Rabbit
Felids
Ferret
Mink
Explain the physiology of induced ovulators
Have nerve which trigor the surge center to have a surge release of GnRH and then LH.
Female is in estrus and therefore has a dominant follicle ready for ovulation
What can an anovulatory cycle be defined as?
A cycle that ovary failed to release the ovum
In general what are signs of anovulatory cycle?
Small ovaries
No Corpus Lutea
What happens to dominant follicles in anovulatory cycle?
Will never reach pre-ovulatory follicle size and will regress
What occurs to some follicles during anovuatory cycle?
Keep growing and become a cyst
One reason for anovatory cycle?
Little amounts of estradiol produced by follicle
Therefore no surge of GnRH
No surge of LH
