practice midterm 1 Flashcards
what is the ploidy of an oocyte of a primordial follicle at birth
diploid
what is the ploidy of a spermatogonium at birth
diploid
from a single meiosis, how many mature sperm will come from a single spermatogonium
four
from a single meiosis, how many oocytes will complete meiosis from a single oogonium, if we assume that fertilization occurs
one
why is the caveat “if we assume fertilization occurs” important in preceding question
because fertilization is required to complete meiosis
no fertilization = 0 completion
if a female human was able to make both male and female gametes, and one of her sperm fertilized one of her own eggs, would the resulting offspring be genetically identical to her? why or why not
not genetically identical, there would be variability introduced into the genome via crossing over and independent assortment, as well as possibly new mutations that might have occurred
where would you expect to find receptors for GnRH, LH, and FSH in a human male
GnRH: anterior pituitary (LH or FSH cells)
LH: leydig cells
FSH: sertoli cells
a person has low levels of LH and FSH in circulation. dr. smartypants suggests giving a prolonged infusion of GnRH to stimulate increases in these hormones. do you agree with them, why or why not?
do not agree; GnRH needs to be released in a pulsatile fashion to elicit LH and FSH release
a prolonged infusion would actually decrease release of FSH/LH by internalizing GnRH receptors on FSH/LH neurons
what happens to GnRH release when there is a moderate (as opposed to low or high levels) amount of circulating estradiol levels? why?
levels of GnRH are decreased with moderate estradiol levels because rising estradiol inhibits KISSpeptin neurons in the ARC. this inhibition reduces the amount of KISS peptin released which results in less GnRH released
what would happen to the maturation of sperm if we added forskolin, a drug that activates adenylase cyclase, to the testes?
we would expect more numbers of mature sperm to be produced
-increased cAMP in leydig cells would result in increased testosterone production
-increased cAMP in sertoli cells will increase gene transcription and release of different products (SCF and GDNF) that drive sperm maturation
at which follicular stage does the antrum first appear
tertiary
what would happen to estradiol production if we blocked cAMP signaling in internal theca cells, why?
-estradiol production would decrease
-cAMP signaling in internal theca cells produces androstenedione and testosterone that granulosa cells need to produce estradiol
-less androstenedione/testosterone = less estradiol
if we blocked estradiol receptors in granulosa cells, what would happen to progesterone production
decrease, granulosa cells would not start to express LH receptors
-won’t make enzymes that convert cholesterol to progesterone
if we blocked estradiol receptors in KISS neurons in AVPV nucleus, what would happen to LH surge
-KISS neurons of AVPV are activated by high amounts of estradiol
-won’t release KISS peptin onto GnRH neurons, so GnRH levels will be very low
-decreased LH production
if we blocked estradiol receptors in epithelial/stromal cells of the uterus, what would happen to endometrial thickness
-decrease; stromal cells of endometrium will not divide = no thickening of endometrium
