Reproductive Cyclicity (Chapter 8) Flashcards
(21 cards)
Which hormone is responsible for luteinization?
LH (luteinizing hormone)
Does progesterone have a positive or negative feedback on the hypothalamus (GnRH)?
Negative
What causes a drop in progesterone levels, and what effect does that have on LH, FSH, and GnRH?
Luteolysis (prostaglandin), which causes an increase in GnRH and an subsequent increase in FSH and LH
What specifically happens to FSH and LH during proestrual follicular development?
[Inhibin] increases, causing a decrease in FSH
[Estradiol] increases, causing a preovulatory LH surge
What are the two feedbacks that estradiol has?
Negative feedback on FSH
Positive feedback on the Surge Center (LH)
What hormone stimulates the surge in LH?
GnRH
Why does FSH have a lower and wider peak in concentration during estrus when compared to LH?
FSH is being inhibited by Inhibin (low peak)
The half-life of FSH is longer (wide)
When a follicle gets bigger, what does it produce more of to block the growth of the other follicles?
Inhibin
What does FSH prevent, how do we over ride Inhibin and what does this cause?
FSH prevents atresia
We can give shots of FSH to over ride Inhibin, which will cause super ovulation
What is super ovulation and how do we achieve this?
Its all follicles, that a female can naturally recruit, becoming dominant
We can achieve this through FSH shots
(T/F) A single cow has a set number of follicles she can recruit
True
(T/F) We can get embryos from pregnant animals
True, they continue to have follicles even after pregnancy has started
What happens to the LH pulse during the LH surge?
The frequency of the pulses exceeds the half-life of LH, causing the surge
The theca interna cells only has receptors for what type of hormone and what is it responsible for converting?
LH receptors
Converts cholesterol into testosterone
What cell type has only FSH receptors and what is it responsible for converting?
Granulosal cells
Converts testosterone into estradiol (via aromatase)
What two cells are apart of the Two Cell Model?
Granulosal cells and theca interna cells
Estradiol cause what three functions to increase in the brain?
Lordosis (heat stance), Phonation (vocalization), and physical activity
What are some functions in the reproductive tract that are increased due to estradiol?
Blood flow, edema in tissues, mucosal secretion, smooth muscle motility
What two follicular characteristics are needed for ovulation?
Increased follicular pressure
Weakening of follicular wall
What enzyme degrades the matrix of the follicular wall and what shift in hormones is responsible for this?
Collagenase
Shift from estrogen to progesterone (caused by LH surge)
The removal of what via the breakdown of what is triggered by the LH surge and makes fertilization possible?
Meiotic inhibition
Breakdown of gap junction between granulosal cells and oocyte
