Reproduction II/III/IV: Female Reproduction Flashcards
What is the fundamental reproductive unit of the ovary?
follicle
RnRH is activated at puberty by ______ in the _______.
kisspeptin; hypothalamus
HPG axis feedback mechanisms are responsible for generation of what?
cyclical monthly pattern of hormone secretion called the “menstrual rhythm”
The menstrual cycle consists of which 2 cycles?
ovarian cycle and uterine cycle, due to physiological changes in these two organs
___ levels are much higher than ____ levels during periods of reproductive quiescence.
FSH; LH
This maintains a lower level of estradiol synthesis during these life stages.
What do increased LH levels stimulate during puberty and reproductive years?
stimulate steroidogenesis in the ovary, causing elevated E2 levels and the ultimate generation of (+) feedback loops that promote ovulation
What are the functions of LH and FSH in the female reproductive system?
- LH: stimulates biosynthesis of estrogens (steroidogenesis) and induces ovulation and luteinization
- FSH: stimulates follicular development and conversion of androgen precursors to estradiol
What are the features of theca vs. granulosa cells?
- theca: produce androgens and progestins; only have LH receptors
- granulosa: produce estrogens, progestins, inhibins, and activins; have both LH and FSH receptors
What are the 3 phases of the ovarian vs. endometrial (uterine) cycle?
- ovarian: follicular, ovulatory, and luteal phase
- endometrial: menstrual, proliferative, and secretory phase
What is required for development from primordial follicle to primary follicle?
FSH stimulation; this can happen in utero
What is the dominant follicle based on?
sensitivity to FSH and local paracrine actions of AMH
For how long is the primary oocyte arrested in the diplotene stage?
until the LH surge
In the Graafian (“dominant”) follicle, what are the characteristic features?
Granulosa cells stratify into: 1) Mural cells 2) Cumulus cells 3) Antral cells Characterized by enlargement of antrum and appearance of cumulus oophorous. Exponential growth continues with large amounts of antral fluid.
Why is FSH high at the end of the ovarian cycle?
High FSH is important for recruiting a new cohort of follicles to enter the follicular phase.
What is the difference b/t inhibin B and inhibin A?
- inhibin B: produced by follicles, positive paracrine effect in thecal cells to augment steroidogenesis, negative feedback on FSH
- inhibin A: produced by corpus luteum, does not contribute to negative feedback on FSH during luteal phase
The LH surge requires a sustained exposure to __________.
critical concentrations of estradiol
The corpus luteum is the new ___________ formed from a ruptured follicle.
endocrine unit
What does the corpus luteum secrete/provide?
It secretes large amounts of progesterone and provides gonadal steroids that optimize implantation and maintain the zygote.
What happens to the corpus luteum if there is no fertilization?
regresses, undergoes “luteolysis,” and becomes necrotic; fibrous scar tissue is formed (corpus albicans)
Loss of LH at the end of the luteal phase will cause the corpus luteum to degrade unless what happens?
it is “rescued” by the equivalent hormone secreted by implantation of a fertilized embryo– HCG
What are the 3 layers of the uterus?
from innermost to outermost- endometrium, myometrium, perimetrium
(the cervix does NOT have an endometrial layer)