Female Reproductive Physiology Flashcards
oogenesis
production of female game
____ oocytes undergo meioisis 1 to produce: ___ oocytes that undergo meiosis 2 to produce: ____
primary, secondary, ova
Three key differences between oogenesis and spermatogenesis
(1) production of primary oocytes occurs only in fetus (2) in primary oocytes, meiosis is arrested in late prophase 1 and resumes years later, if at all (3) in secondary oocytes, meiosis is arrested in metaphase 2 and is only completed if fertilization occurs
ovarian follicle
functional unit of ovary that encloses a single oocyte; surrounded by pre-granulosa and granulosa cells
pre-granulosa cells
if single layer of cells present
granulosa cells
if more than one layer present
primordial follicle
single layer of squamous pre-granulosa cells surrounding primary oocyte
primary follicles
have single layer of cuboidal pre-granulosa cells surrounding primary oocyte
secondary follicles
have multiple layers of granulosa cells surrounding primary oocyte
vesicular (antral) follicles
(tertiary follicles) have a fluid-filled cavity called an antrum
follicles have two fates
atresia, ovulation
atresia
apoptosis of oocyte and surrounding cells
ovulation
each month after pubery, a select few primary oocytes are activated
After division of meiosis 1 is completed, two haploid cells of different sizes are produced
first polar body, secondary oocyte
first polar body
smaller cell that is almost devoid of cytoplasm
secondary oocyte
large cell with almost all of mother cell cytoplasm and organelles
If penetrated by sperm, secondary oocyte quickly completes meiosis 2, yielding:
ovum or second polar body
ovum
large cell with enough cytoplasm to nourish fertilized egg for 6-7 day journey to uterus
second polar body
small cell lacking cytoplasm degenerates and dies
Two phases of maturation of follicles
pre-antral phase (involves intrafollicular paracrines); antral phase (stimulated by FSH and LH)
antral phase
dominant follicle is selected, primary oocyte resumes meiosis 1
primordial follicles
squamous like cells surrounding primary oocyte become cuboidal, and oocyte enlarges
zona pellucida
encapsulates oocyte, formed when oocyte secretes glycoprotein-rich substances
corona radiata
isolated oocyte with its surrounding granulosa cells
after oocyte and corona radiata are ejected, ruptured follicle transforms into glandular structure called ___ ___
corpus lutem
ovarian cycle
monthly series of events associated with maturation of egg
follicular phase
period of vesicular follicle growth
luteal phase
period of corpus lutem activity
Mittelschmerz
twinge of pain sometimes felt at ovulation by some women
What happens during ovulation?
ballooning ovary wall ruptures, expelling secondary oocyte with its corona radiata into peritoneal cavity
corpus hemorrhagicum
after ovulation, ruptured follicle collapses, and antrum fills with clotted blood
corpus lutem
remaining granulosa cells and internal thecal cells enlarge to form this
corpus albicans (scar)
corpus lutem degenerates into this if no pregnancy occurs
Establishing the ovarian cycle
Before puberty, ovaries secrete small amounts of estrogen,
inhibiting hypothalamic release of GnRH; As puberty nears, if leptin levels are adequate, hypothalamus
becomes less estrogen-sensitive, so GnRH is released,
stimulating FSH and LH release by pituitary that then acts on
ovaries
hormonal interaction during ovarian cycle
(1) GnRH stimulates FSH and LH secretion (2) FSH and LH stimulate follicles to grow, mature, and secrete sex hormones (3) negative feedback inhibits gonadotropin release (4) positive feedback stimulates gonadotropin release (5) LH surge triggers ovulation and formation of the corpus luteum (6) negative feedback inhibits LH and FSH release
uterine (menstrual) cycle
cyclic series of changes in endometrium that occur in response to fluctuating ovarian hormone levels
three phases of uterine cycle
days 1-5 menstrual phase; days 6-14 proliferative (preovulatory) phase; days 15-28 secretory (postovulatory) phase
menstrual phase
(1) ovarian hormones are at lowest levels (2) gonadotropin levels are beginning to rise (3) stratum functionalis detaches from uterine wall and is shed (4) by day 5, growing ovarian follicles start to produce more estrogen
proliferative (preovulatory) phase
(1) rising estrogen levels prompt generation of new stratum functionalis layer (2) estrogen also increases synthesis of progesterone receptors in endometrium (3) thins out normally thick, sticky cervical mucus to facilitate sperm passage
secretory (postovulatory) phase
(1) phase that is most consistent in duration (2) endometrium prepares for embryo to implant (3) rising progesterone levels from corpus luteum prompt several things
In the secretory phase, rising progesterone levels from corpus luteum prompt:
(1) functional layer to become a secretory mucosa (2) endometrial glands to enlarge and secrete nutrients into uterine cavity (3) thickened mucus to form cervical mucus plug that blocks entry of more sperm, pathogens, or debris
What happens during the secretory phase if fertilization doesn’t occur?
(1) corpus luteum degenerates toward end of phase and progesterone levels fall (2) endometrial cells die, and glands regress (3) spiral arteries constrict again, then relax and open wide, causing a rush of blood into weakened capillary beds (4) blood vessels fragment, and functional layer sloughs off and uterine cycle starts over
Extremely strenuous physical activity can delay menarche in girls and disrupt normal menstrual cycle in adult women. It can cause..
amenorrhea (cessation of menstruation)
