23 - Reproductive Physiology I (online) Flashcards
fetal stages of oogenesis
- oogonia (in fetal ovaries) produce
- primary oocytes in primordial follicles (in ovary)
roughly 2 million at birth, they are diploid (46 sets of chromosomes)
amount of oocytes throughout life, # of eggs released through life
at ~11 years: over 300 000 primary oocytes
menopause: 0 - no more functional primary oocytes
maximum of 500 eggs released
primordial to mature follicle
GN
- primordial follicle: flat follicular cells expand
- once expanded into cuboidal granulosa cells, it’s a primary follicle
- zona pellucida (thick protein coat on the egg) begins to form
- layers of granulosa build up
- granulosa secrete fluid and form intracellular spaces, it’s a secondary follicle now
- intracellular spaces form one large antrum, making mature follicle
- granulosa cells surrounding the egg are called corona radiata
oogenisis stages
(after birth)
- primary oocytes in primordial follicles stuck in prophase of meiosis I
- some develop primary follicles and restart meiosis I
- become secondary oocytes with 3 polar bodies each in secondary follicle
- one secondary oocyte releases from ovary at ovulation
- leaves behind corpus luteum (remains of follicle)
- meiosis II begins when sperm contacts the egg
ovarian cycle
(basic phases)
GN quiz
follicular phase:
- egg and granulosa cells develop until ovulation
luteal phase:
- leftover follicle bits release hormones to prepare the lining of the uterus for a fertilized egg
Homeostasis in the ovary (hormonal)
GN hormonal cycle
- low estrogen
- GnRH release
- LH (stimulate estrogen release) and FSH (leads to follicle growth)
- estrogen levels will inhibit GnRH, LH and FSH
- follicle continues to produce estrogen
- high enough estrogen levels stimulate GnRH, LH and FSH
- LH surge causes follicle to rupture, egg releases
draw hormone level diagrams throughout the menstrual cycle
GN graphs
- gonadotropins (LH and FSH)
- ovarian steroids (estrogen and progesterone)
layers of the uterus
superficial to deep
- myometrium
- endometrium
- stratum basalis
- stratum functionalis (contains endometrial glands)
- uterine cavity (lumen)
menstrual/uterine cycle
overlay with ovarian cycle GN
- (day 1-4) menstrual phase (bleeding): stratum functionalis sheds
- (day 4-14) proliferative phase: endometrial glands and blood vessels develop
- (day 14-28) secretory phase: glands produce secretions
relationship between ovarian and menstrual cycles
causes of major events
- follicles produce estrogens, promote proliferative phase
- corpus luteum causes endometrial glands to produce secretions
- estrogen and progesterone drop, stratum functionalis sheds
how pregnancy changes the menstrual cycle
- prevents degeneration of the corpus luteum because implanting embryo releases human chorionic gonadotropin (hCG)
- hCG stimulates corpus luteum to produce progesterone and estrogen
- inhibits uterine contractions and shedding of stratum functionalis
sperm diagram
(sections and their purpose)
GN
- acrosome: digestive enzymes to penetrate the zona pellucida
- nucleus: contains haploid # of chromosomes (23 sets)
- midpiece: supplies energy for the flagellum
- flagellum: propels sperm to swim
spermatogenesis
- spermatogonia constantly divide
- form primary spermatocytes
- meiosis I
- secondary spermatocytes
- meiosis 2
- spermatids into
- spermatozoa
every spermatogonia creates 8 spermatozoa, every spermatocyte creates 4 spermatozoa
male urogenital organs
GN quiz
- vas deferens
- ureter
- seminal vescicles
- prostate
- urethra
- ejaculatory duct
- urethra
semen vs sperm
semen is the fluid itself, sperm is a component of semen
