M1 - big points of repro physio Flashcards
male differentiation
SRY gene –> TDF protein –> SOX 9 protein.
TDF, SOX9 develop indeterminate gonads into testes.
Testosterone develops the Wolffian ducts.
AMH degenerates Mullerian ducts.
Testosterone –> DHT for development of external genitalia
DAX-1
Expresses proteins that cause female sexual reproduction.
Suppress expression of proteins that lead to male differentiation
female differentiation
DAX-1 triggers female proteins, suppresses male proteins.
Without SRY/TDF/testosterone, Wolffian ducts degenerate.
Without AMH, Mullerian ducts persist.
Without DHT, no male external genitalia.
body transitions during puberty, and hormone that accomplishes it
- external genital development (T, E)
- growth spurt (E)
- increased musculature, beard, deep voice (T)
- breast development, increased fat deposits (E)
kisspeptin
POTENT STIMULATOR OF GnRH.
secreted within hypothalamus
leptin
Increases GnRH secretion.
Enhances kisspeptide secretion.
secreted from fat cells
effect of estradiol in pubertal growth
Estradiol acts directly on growth plate.
Triggers pituitary to increase release of GH.
GH causes liver to secrete IGF-1, further stimulating growth.
After accelerated growth, estrogen causes closure of growth plates.
MALES:
testosterone is converted to estrogen by aromatase.
theca cells
Outside BM.
LH stimulates theca cells to produce androgens.
granulosa cells
Inside BM.
FSH stimulates granulosa cells to convert androgens (from theca) to estrogens by aromatase.
FSH stimulates granulosa cells to produce inhibin –> negative feedback on FSH.
FSH levels during menstrual cycle
Initially an increase in FSH due to a loss of negative feedback from previous cycle. (FSH rises in follicular phase)
Drives development of follicles.
Causes increase of estrogen.
Increased estrogen –> negative feedback on FSH.
Inhibin also causes decrease.
LH levels during menstrual cycle
LH surge causes ovulation (triggered by peak estrogen level).
Follicle forms corpus luteum –> produces progesterone.
Estradiol levels during menstrual cycle
Rises in follicular phases, peaks just before ovulation.
Increased levels after increase in FSH (delayed).
Negative feedback causes FSH levels to fall.
GROWTH OF ENDOMETRIUM to get ready for luteal phase.
PEAK LEVEL OF ESTROGEN CAUSES LH SURGE (estrogen –> kisspeptin –> GnRH –> LH surge)
progesterone levels during menstrual cycle
Low during follicular phase.
Rises during luteal phase.
Prepares uterus for implantation/pregnancy.
inhibin levels during menstrual cycle
Rise at same time as estradiol (follicular phase).
Another factor to drive FSH down.
process of fertilization
Sperm makes contact –> releases enzymes to burrow through ZP
Once thru ZP, releases enzymes to activate cortical granules –> release enzymes that change ZP so no more sperm can enter