L3: Female Reproductive Physiology Flashcards
what factors keep follicles from developing between birth + puberty
- oocyte inhibiting factor OIF keeps oocytes in Prophase 1
- luteinizing-inhibiting factors LIF prevents granulosa cells from becoming luteal tissue
layer of glycoproteins b/w oocyte and granulosa cells
zona pellucida
as follicles mature, a fluid filled _________ develops within the granulosa cells
antrum
what are the 2 phases of the ovarian cycle
follicular phase- maturing follicles
luteal phase- corpus luteum
what are the 3 cell types within the maturing follicle
- primary oocyte
- inner layer of granulosa cells
- outer layer of theca cells
when does the follicle start to become sensitive to FSH
after formation of the antrum
occurs when follicular cells release enzymes that weaken the follicular wall
ovulation
during ovulation, _____ drives differentiation into the corpus luteum
Leutinizing hormone
what is the ‘yellow body’ observed during in the corpus luteum
storage of cholesterol
corpus luteum: remaining follicular cells convert to luteal cells & produce large amounts of …?
steroid hormone
what happens to the corpus luteum if no fertilization occurs
becomes corpus albicans = white body forms due to formation of fibrous tissue
_______ ovulators have cycles regulated by internal hormonal cycles
spontaneous
what hormone signals the release of gonadotropins in spontaneous ovulators
estrogen
______ ovulators are animals that require copulation for ovulation
induced
in induced ovulators, ______ replaces estrogen as the signal that releases gonadotropins
copulation
hormone synthesis occurs during the _____ phase of the ovarian cycle
luteal
LH stimulates _________ in the thecal cells of the corpus luteum
cholesterol desmolase
FSH stimulates ______ in the granulosa cells
aromatase
enzymes for _________ synthesis are only active during the luteal phase
progesterone
3B-hydroxysteroid dehydroxygenase
negative feedback of _______ and _______ inhibits FSH secretion
estrogen + inhibin
LH secretion gradually ________ during the follicular stage
increases
the effects of ______ changes negative feedback to positive feedback, leading to an LH surge
estrogen
what occurs during the LH stage
- meiosis of oocyte resumes
- prostaglandin release breaks down follicular wall
- follicular cells differentiate into luteal cells
- ovulation occurs!
ovulation occurs following what stage
Luteal
what hormone has a strong negative feedback and suppresses a second LH surge after ovulation
progesterone
______ synthesis halts upon ovulation but the levels of this hormone gradually increase
estrogen
After ovulation, in the absence of pregnancy, __________ causes a regression of the ______ in cows, horses, gaots and sheep
PGF2α, corpus luteum
PGF2α has no role in what animals
primates, queens and bitches
what inhibits PGF2α release from the uterus
pregnancy
why do most animals lack a menstrual phase
due to overlap in the late luteal phase w/ the early part of the follicular phase
what occurs during to the endometrium during the proliferative phase of the uterine cycle
endometrium regenerates
what occurs to the endometrium during the secretory phase of the uterine cycle
becomes enriched w/ glycogen to nourish an incoming embryo
during the follicular phase, the main hormone is ?
estrogen
during the luteal phase, the main hormone is ?
progesterone
LH stimulates the development and maintenance of ….
corpus luteum
what hormones does the corpus luteum secrete
progesterone and estrogen
ovulation occurs at the end of …
estrous
early post ovulatory phase during which corpus luteum begins to develop during the estrous cycle
Metestrus
phase of mature luteal activity that begins 4 days after ovulation and ends with the regression of the corpus luteum
Diestrus
phase of estrus cycle that begins after corpus luteum regression and ends w/ onset of estrus
proestrus
phase of estrous cycle characterized by rapid follicle development that leads to ovulation and the onset of sexual receptivity
proestrus
what generates follicular waves
FSH
dominant follicles are more sensitive to FSH since they have more _______, and thus are selected for further development
FSH receptors
FSH stimulates ______ cell growth, increases _______ activity and synthesizes ______ to produce estradiol
granulosa cell growth
increase aromatase activity
synthesize inhibin to produce estradiol
inhibin blocks _______ synthesis / secretion
FSH
inhibin represents a parallel neg feedback mech besides estrogen
when _____ is high, it inhibits final development and ovulation
progesterone
if _____ is low, the dominant follicle can enter ovulation
progesterone
in induced ovulators, how does mating induce ovulation
via neural stimuluation of GnRH which leads to LH surge and then ovulation
what event signals the end of the follicular phase and the beginning of the luteal phase
rupture of the follicular wall
what 3 things facilitate ovulation
hyperemia
collagenase synthesis by theca cells
prostaglandin release
prostaglandin is released by the ______ and stimulates what
ovary
smooth muscle contractions
upon stimulation by FSH, granulosa cells convert ______ into _______
androgen into estrogen
In what animals does PGF2α cause the regression of the corpus luteum at ~14days
cows, horses, sheep, goats, pigs
at what age to queens reach sexual maturity
4-12 months
when does estrus occur
following the end of ovulation, during a period of high estrogen release from mature follicles
what must occur right before ovulation
LH surge
what are the stages of the follicular wave
- recruitment phase
- selection
- dominance
- atresia
during the follicular wave, what makes a follicle dominant
greater sensitivity to FSH due to having more FSH receptors
explain the feedback mechanism between FSH and inhibin
FSH synthesizes inhibin, inhibin blocks FSH synthesis and secretion
during the follicular wave, what does FSH stimulate
- granulosa cell growth
- increases aromatase activity
- synthesize inhibin
- produce estradiol
what stimulates the follicular selection phase of the follicular wave
follicular growth (stimulated by FSH)
how does the recruitment phase of follicular waves vary between cows+horses vs other sepcies
cows+horses: one follicle is selected to beocme the dominant follicle while the rest become atretic
other species: more than one follicle is selected, multiple dominant follicles
