Menarche Flashcards
(95 cards)
What is the time frame of the follicular phase of the ovulatory cycle?
it begins with the onset of menstruation and culminates in the preovulatory surge of LH
what is the time frame of the luteal phase of the ovulatory cycle?
it begins with the onset of the preovulatory LH surge and ends with the first day of menses
what is the effect of the decreasing levels of estradiol and progesterone from the regressing corpus luteum of the preceding cycle?
it is going to initiate an increase in FSH by a negative feedback mechanism, which stimulates follicular growth and estradiol secretion
What does LH stimulate in the ovarian follicle?
the theca cells to produce andorgens
what does FSH stimulate in the ovarian follicle?
the granulosa cells to convert the androgens made in the theca cells into estrogens
what happens to the LH and FSH levels during the luteal phase?
they are significantly suppressed through the negative feedback effect of the elevated circulating estradiol and progesterone
what happens to the levels of progesterone and estrogen near the end of the luteal phase if conception does not occur?
they will decline
what type of hormone is GnRH?
a decapeptide synthesized in the arcuate nucleus
what effect does estradiol have on the hypothalamus?
it appears to enhance the hypothalamic release of GnRH and induce the midcycle LH surge
what effect do the gonadotropins have on GnRH release?
an inhibitory effect
when do estrogen levels generally reach a maximum peak?
1 day before the midcycle LH surge
during the follicular development, the ovary secretes only a very small amount of progesterone. Where does the bulk of the progesterone come from?
the peripheral conversion of the adrenal pregnenolone and pregnenolone sulfate
prior to ovulation the unruptured luteinizing graafian follicle begins to produce what?
increasing amounts of progesterone
at about 8-10 weeks of fetal development, what do the oocytes become surrounded by?
the precursor granulosa cells- this complex is called the primordial follicle
what do the inner most layer of the granulosa cells of the cumulus oophorus become?
the corona radiata
what does the corpus luteum produce?
copious amounts of progesterone and some estradiol
what is the endometrium responsive to?
circulating progestins, androgens, and estrogens
what kind of arteries does the functional layer of the endometrium contain?
spiral arteries
what kind of arteries does the inner/ basalis layer of the endometrium contain?
straight/ basal arteries
the cyclic changes in the histophysiology of the endometrium can be divided into 3 stages. What are these stages?
the menstrual phase, the proliferative (estrogenic) phase, and the secretory (progestational) phase
what is the proliferative phase characterized by?
endometrial growth/proliferation secondary to estrogenic stimulation/ increase in the length of the spiral arteries and numerous mitoses can be seen in these tissues
when does the secretory phase occur?
following ovulation
what stimulates the secretory phase?
progesterone secretion by the corpus luteum stimulates the glandular cells to secrete mucus, glycogen, and other substances
does mitosis occur during the secretory phase?
it is rare