objective 9 pt 2 Flashcards
are present in both male and female, but normally function only in female
main function is milk production to nourish newborn
mammary glands
pigmented skin surrounding nipple
areola
attach breast to underlying muscle
suspensory ligaments
production of female gametes takes years to complete
oogenesis
multiplied by mitosis to produce primary oocytes
oogonia
begin meiosis but stall in prophase 1
primary oocytes (2n)
large cell with almost all of mother cell cytoplasm and organelles
secondary oocyte
small cell almost devoid of cytoplasm
first polar body
monthly (~28 days) series of events associated with maturation of egg
ovarian cycle
occurring mid-cycle between phases
ovulation
period of vesicular follicle growth (days 1-14); maturation
several follicles are
stimulated to grow; only 1 releases egg
* Triggered by rising levels of FSH
* FSH levels drop around middle of follicular phase
* Causes only one follicle, dominant follicle, to
be selected to continue
* How dominant follicle is chosen is uncertain
follicular phase
period of corpus luteum activity (14-28 days)
begins after ovulation and ends when
you get next period
* During ovulation, the egg bursts from its follicle, but
the ruptured follicle stays on the surface of the
ovary.
* For the next two weeks or so, the follicle transforms
into a structure known as the corpus luteum.
* Corpus luteum starts releasing progesterone and
estrogen to maintain the thickened lining of the
uterus, waiting for a fertilized egg to implant)
* If a fertilized egg implants in the lining of the uterus,
HCG is secreted, the hormone that is detected in a
urine test for pregnancy.
* The corpus luteum keeps producing the raised
levels of progesterone that are needed to maintain
the thickened lining of the uterus, ~3 mths
* If pregnancy does not occur, the corpus luteum
withers and dies into corpus albicans, in 10 days.
* The drop in progesterone levels causes the lining of
the uterus to fall away. This is known as
menstruation. The cycle then repeats.
luteal phase
the release of a mature egg from the ovary. this usually occurs mid-cycle, around two weeks or so before menstruation starts
rising levels of LH cause ovary wall to rupture, expelling secondary oocyte into peritoneal cavity
ovulation
twinge of pain sometimes felt at ovulation by some women
mittelschmerz
what are the hormonal interactions during ovarian cycle
- GnRH stimulates Gonadotropin FSH and LH
secretion - FSH and LH stimulate follicles to grow, mature,
and secrete sex hormones - Negative feedback inhibits gonadotropin release
- Positive feedback stimulates gonadotropin release
- LH surge triggers ovulation and formation of
the corpus luteum - Negative feedback inhibits LH and FSH
release
- FSH stimulates granulosa cells to release
estrogen, and LH prods thecal cells to produce
androgens, which granulosa converts to
estrogens
FSH and LH stimulate follicles to grow, mature,
and secrete sex hormones
- Increasing levels of progesterone and estrogen exert
negative feedback inhibition on FSH and LH release. - Only dominant follicle survives the dip in FSH
Negative feedback inhibits gonadotropin release
- Once dominant follicle becomes a mature vesicular
follicle, just before ovulation, the follicle produces
high levels of estrogens. - When levels reach a critical high value, a brief positive
feedback occurs on brain and anterior pituitary - Triggers LH surge on day 13
Positive feedback stimulates gonadotropin release
- High estrogen levels trigger release of stored
LH, and some FSH at midcycle
LH surge triggers ovulation and formation of
the corpus luteum
- Negative feedback from rising progesterone
and estrogen levels inhibits LH and FSH release - Inhibin from corpus luteum and granulosa
cells, enhances inhibitory effect - Declining LH ends luteal activity and inhibits
follicle development
Negative feedback inhibits LH and FSH
release
cyclic series of changes
in endometrium that occur in response to
fluctuating ovarian hormone levels
uterine (menstrual) cycle
what are the 3 phases of the uterine cycle>
menstrual phase
proliferative phase
secretory phase
- Ovarian hormones are at lowest levels
- Gonadotropin levels are beginning to rise
- Stratum functionalis detaches from uterine
wall and is shed - Menstrual flow of blood and tissue lasts 3-5
days - By day 4, growing ovarian follicles start to
produce more estrogen
menstrual phase (0-4 days)
- Rising estrogen levels prompt regeneration of new
stratum functionalis layer by the basal layer. - Glands enlarge and spiral arteries increase in
number. - Estrogen also increases synthesis of progesterone
receptors in endometrium - Thins out normally thick, sticky cervical mucus to
facilitate sperm passage - Ovulation occurs at end of proliferative phase
on day 14
proliferative phase (5-14 days)
