Female Reproductive Cycle Flashcards
the female reproductive cycle consists of
two hormone controlled cycles that occur simultaneously during a one-month period
ovarian cycle
events associated with maturation and release of an oocyte
uterine cycle
describes regular, recurring changes in uterus
a “typical” reproductive cycle ranges from
24 to 35 days but individual variations in length are normal and are usuallly related to physiological and/or psychological stressors
in hypothetical cycle of 28 days, on day 1:
menstrual bleeding begins
on day 2 or 3
the hypothalamus produces and releases GnRH to stimulate the anterior lobe of the pituitary gland to release FSH
pre-ovulatory period
time between the end of menstrual bleeding and ovulation, typically occuring from Day 6 to Day 13 of a 28 day cycle
follicular phase
events associated with ovarian cycle
proliferative phase
events associated with uterine cycle
rising levels of FSH trigger
the development of several primary follicles in the ovaries
most of these follicles undrego
artesia, but one eventually becomes a Graafian follicle
secretion of
estradiol from granulosa cells in developing follicles cause changes to occur in the female reproductive tract
stratum basalis produces
a new stratum functionalis
cervical mucus becomes
thinner to facilitate passage of sperm through cervix
lining of vagina
thickens and becomes more secretory
rising levels of estradiol
exert positive feedback on the hypothalamus, which cause it to continue releasing GnRH
GnRH stimulates
anterior lobe of pituiatry gland to release a surge of LH
ovulation typically occurs on
Day 14 of a 28 day cycle
the LH surge causes
a Graafian follicle to rupture and release its secondary oocyte and polar body toward a Fallopian tube
remnants of the Graafian follicle become
a corpus luteum, which secretes progesterone
the post-ovulatory period
time between ovulation and the onset of menstrual bleeding, typically lasting from Day 15 to Day 28 of a 28 day cycle
luteral phase
events associated with ovarian cycle
secretory phase
events associated with uterine cycle
rising levels of progesterone secreted by
corpus luteum exert negative feedback on the hypothalamus, which inhibits the secretion of GnRH
absence of GnRH prevents
anterior lobe of pituitary gland from releasing FSH, so no additional ovarian follicles will develop
rising levels of progesterone stimulate
development of the endometrium
during post-ovulatory period endometrium becomes
even thicker, spongier, more vascular
during post-ovulatory period uterine glands
fill with glycogen in anticipation of fertilized egg
if a fertilized egg implants in the endometrium, the corpus luteum
has to be maintained in order to produce and secrete the hormones needed for pregnancy to continue
if fertilization does not occur, the corpus luteum
degenerates by day 25 of a 28 day cycle
if fertilization does not occur levels of estradiol and progesterone
decline sharply, which triggers menstruation
menstruation occurs from
day 1 to 5
during menstruation a sharp decline in progesterone levels
constricts the spiral arteries that supply the endometrium causing ischemia that leads to the death of the endometrial tissue
during menstruation the stratum functionalis
starts to slough off, produces menstrual fluid that contains blood clots, uterine fluid, vaginal cells, endometrial tissue
total menstrual discharge ranges from
50 to 150 mL a day
during menstruation a sharp decline in progesterone
removes negative feedback inhibition on hypothalamus
during menstruation GnRH is again produced and released stimulate
anterior lobe of pituitary gland to release FSH and LH to initiate a new reproductive cycle
during menstruation a sharp decline in levels of progesterone removes
the block on prostaglandins
prostaglandins trigger
contractions of uterine smooth muscle that may be responsible from cramps associated with menstruation
premenstrual syndrome
a collection of physical, physiological, and emotional symptoms that appear between three and ten days prior to the start of the menses
physical symptoms of PMS
fatigue, abdominal distention, fluid retention, breast enlargement and soreness, headaches, increased appetite, and muscle aches
emotional symptoms of PMS
irritability, anxiety, depression and sudden mood swings
PMS is probably causes by
tissue sensitivity to changing levels of estradiol and or progesterone
treatment of PMS
vitamins, diuretics, and prostaglandin inhibitors may reduce symptoms
******notes on complications
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menopause
a female’s monthly reproductive cycle comes to a halt between ages of 45 and 60
as a female grows older,
her ovaries become less responsive to FSH and LH
number of primary follicles that develop during each cycle in a woman in menopause
becomes smaller
in menopause reduced levels of estradiol fail to
trigger ovulation, so a corpus luteum does not form
during menopause estradiol and progesterone are
secreted less and periods become irregular
during menopause low levels of progesterone cannot
exert negative feedback on the hypothalamus, so GnRH is secreted, FSH and LH are released and the adrenal glands produce more androgens
rising levels of androgens
further reduce ovarian function and can cause voice to deepen, facial hair to become coarser and darker, breasts to shrink
changing hormone levels can cause
dizziness, headaches, insomnia, anxiety, depression
declining levels of estradiol cause
breasts, labia and vagina to atrophy; intercourse becomes uncomfortable and/or painful because of reduced vaginal lubrication
Periodic surges of estradiol may trigger
sudden intense “hot flashes” that spread through head, neck, and body
hot flashes are caused by
vasodilation of dermal blood vessels that allow blood to rush to skin
hot flashes are accompanied by
profuse sweating; leads to rapid cooling and a “cold flash”
