Flashcards in Introduction to the Reproductive System: Physiology and Biochemistry Deck (22):
The conversion of _______________ is the rate-limiting step in sex-hormone synthesis.
cholesterol to pregnenolone (by 20,22-desmolase)
Progestins are _______ carbons and androgens are _______ carbons.
How many carbons are in estrogen?
What effects do androgens have?
Bone and muscle: growth
Skin: sebum production
The main tissues with progesterone receptors are ___________.
uterus, ovaries, breast
What part of the hypothalamus releases GnRH?
Arcuate nucleus and pre-optic area
LH acts on ________.
Leydig cells, which release androgens
FSH acts on ___________.
Sertoli cells, which releases aromatase, inhibin, and growth factors on the Leydig cells
Testosterone has a negative feedback on the ______________.
hypothalamus and pituitary
The positive feedback of ___________ causes the surge of LH.
The secretion of HCG during pregnancy causes lower levels of TSH. Why?
Because it has a homologous skeleton (the AA subunits)
Most male testosterone is produced in the ________.
testes (by Leydig cells)
Most dihydrotestosterone is produced in the _____________.
Androgens are converted to estrogens by ____________.
In males, Sertoli cells produce __________.
In females, which cells produce estrogen?
Granulosa cells of the ovary
Inhibin exerts negative feedback on the ______________.
What happens at midcycle in women?
Estradiol becomes a positive feedback and stimulates a surge of LH and FSH
In females, the Leydig cells are called ________. Both have LH receptors and cannot make estrogen.
How are Sertoli and granulosa cells similar?
Both have FSH receptors, aromatase, and make inhibin
Testosterone works on __________ to stimulate spermatogenesis.