Female Reproductive Physiology Flashcards
What are the ovaries? what is their function?
primary female reproductive organs that produce ova and secrete female sex hormones
what two major hormones do the ovaries secrete?
estrogen
progesterone
what is the function of estrogen?
1) essential for ova maturation
2) establishment of female secondary sexual characteristics
what are the oogonia?
undifferentiated primordial germ cells in fetal ovaries
What is the order of the different cells in oogenesis?
oogonia
primary oocyte
first polar body (degrades) + secondary oocyte
Secondary polar body (degrades) + mature ovum
what is a primary follicle?
oocyte + granulosa cells
what is a primary follicle? what is it’s two possible fates?
oocyte + granulosa cells
1) reach maturity and ovulate
2) degenerate to form scar tissue (atresia)
what is the function of progesterone?
1) important in preparing suitable environment for nourishing a developing embryo/fetus
2) contributes to breast’s ability to produce milk
what occurs in regards to the follicular cells between puberty and menopause?
follicles develop into secondary follicles on cyclic basis
do oogonia go through meiotic division or mitotic? approx. how many oogonia are produced by 5mo. gestation?
mitotically
6-7 million
what happens during the last part of fetal life in regards to oogenesis?
the early steps of the first meiotic division of primary oocytes begin but does not complete it
remains in meiotic arrest for years until they are ready for ovulation
is the primary oocyte haploid or diploid? how many chromosomes do they have?
haploid # of 46 replicated chromosomes
what occurs just before ovulation?
primary oocyte completes its first meiotic division yielding a first polar body that will degenerate and a secondary oocyte
what happens if the secondary oocyte comes in contact with sperm?
sperm entry triggers second meiotic division which produces a secondary haploid polar body (degenerated) and a mature haploid ovum which unites with haploid sperm during fertilization
how many chromosomes should be in the secondary oocyte before fertilization?
23 chromosomes
how long is the typical ovarian cycle?
28 days
what are the 2 phases of the ovarian cycle?
Follicular phase
luteal phase
what are the 2 things that will disrupt the ovarian cycle?
pregnancy and menopause
what differentiates the follicular phase from the luteal phase?
foll - dominated by presence of maturing follicles
lut - characterized by presence of corpus luteum
when does the follicular phase occur in the ovarian cycle?
first half (first 14 days)
what 4 things occur during the follicular phase?
1) granulosa cells of some primary follicles proliferate
2) oocyte inside each follicle increases
3) theca cells in follicle secrete increasing amounts of estrogen
4) rapid follicular growth continues during follicular phase
approx how long does it take for a follicle to mature?
14 days
what is ovulation?
mature follicle ruptures to release oocyte from the ovary and enters to oviduct where it may or may not be fertilized
when does the luteal phase occur in the ovarian cycle?
last 14 days
what occurs during the luteal phase?
old follicular cells undergo structural transformation to form corpus luteum and becomes highly vascularized
when does the corpus luteum become fully functional?
within 4 days after ovulation (~day 18 or less)
what occurs for the next 4-5 days after corpus luteum becomes functional?
continues to increase in size
what happens to the corpus luteum if the ovum is not fertilized?
degenerates within ~14days after its formation
what hormones increase during follicular phase? why?
FSH - to signal ovarian follicle to secrete more estrogen
LH - to trigger ovulation at peak in mid-cycle
what does increase estrogen do to FSH?
feeds back to inhibit FSH secretion which decreases as follicular phase proceeds
what is the function of the corpus luteum in terms of hormones?
secrete estrogen and progesterone during luteal phase
what does progesterone do when secreted by corpus luteum?
Inhibits release of FSH and LH leading to declined pro levels
what is the first step in hormonal effects by LH and FSH?
stimulates the thecal cells in ovarian follicle
what is the second step in hormonal effects by LH and FSH?
on stimulation, the thecal cells convert cholesterol to androgen
what is the third step in hormonal effects by LH and FSH?
androgen diffuses from the thecal cells into the adjacent granulosa cells