Female Reproductive Physiology Flashcards
What is the role of granulosa cells?
provide nutrients such as aa, nucleic acids and pyruvate to support oocyte maturation
What are mural granulosa cells
also called stratum granulosum Form outer wall of the follicle Close to outerlying thecal layers Become highly steroidogenic Remain in the ovary after ovulation
What runs in the medulla of the ovary?
neurovascular elements
What is the cortex of the ovarry composed of?
densely cellular stroma
Ovarian follicles
What gives rise to mroe than 80% of cases of ovarian cancer?
Highly mitogenic population of cells that make up the ovarian surface epithelial
What represents the earliest and simplest follicular structure in the ovary?
primary oocyte with surrounding single layer of preganulosa cells
What is one of the first visible signs of follicle grwoth ?
appearance of cuboidal granulosa cells
Whaat happens once the follicle acquires 3-6 layers of granulosa cells?
secretes paracrine factors that induce nearby stromal cells to differentiate into epithelioid thecal cells
Thecal cells are on the outside of the follicle’s __________
basement membrane
Movement of the follicle from the outer cortex to the inner cortex, allows the follicle to do what?
when closer to the vasculature of the ovarian medulla, follicles release angiogenic factors that induce the development of 1 or 2 arterioles
What happens to the oocyte and endocrine function of the follicle after theca cells start to show increasing differentiation ?
oocyte begins secretion of glycoproteins that form the zona pellucida
Granulosa cells express the FSH receptor but do not produce ovarian hormones
Theca cells produce very little or no androstenedione
What happens once granulosa epithelium increases to 6 or 7 layers?
fluid-filled spaces appear between cells and come together into the antrum
and granulosa is divided into 2 populations
What are cumulus cells?
also called corona radiata
Inner cells surrounding the oocyte
Released from the ovary with the oocyte
Crucial for ability of fibriated end of oviduct to grab and move oocyte through oviduct
What are the 2 populations of granulosa cells?
mural granulosa cells (stratum granulosum) Cumulus cells (corona radiata)
Follicles with antrum gain meitotic competence but still maintain meiotic arrest until when?
midcycle LH surge
What do thecal cells produce once there is a complete antrum?
lots of androstenedione and some testosterone
have LH receptors
What is the function of mural granulosa cells?
Once stimulated by FSH: express aromatase to
convert Testosterone into estradiol - 17b
Convert androstenedione into estrone
also express inhibin B
Later, also have LH receptors
How is only one follicle selected to be dominant?
low levels of estrogen and inhibin exert a negative feedback effect on FSH secretion, select the follicle with the most FSH-ressponsive cells. Other follicles undergo atresia
Before ovulation, follicle presses against wall of ovary to form bulge called what?
stigma
What causes expansion of oocyte complex making it easier for capture by oviduct and easier for sperm to locate?
CDF9 released from oocyte that stimulates cumulus cells to secrete hyaluronic acid
What do sperm produce to allow penetration into cumulus-oocyte complex?
hyaluronidase
What arrests the oocyte in prophase I?
high cAMP levels
What does the LH surge induce in mural granulosa cells? What is the purpose?
Inhibits aromatase expression
Rapid decline in estrogen helps turn off positive feedback on LH secretion
Increases expression of proteins and enzymes to produce progesterone
What cells collapse and fill the antral cavity after ovulation?
Granulosa lutein cells that enlarge and fill with cholesterol esters
