Biology 12 - Reproductive System
menstrual cycle
28-day cycle divided in half by ovulation -ovarian cycle -uterine cycle
oogenesis
development of the egg (once per month, egg released around day 14)
oxytocin
during childbirth -contractions force baby downward -this stretches the cervix -triggers release of oxytocin from P.P. -oxytocin stimulates stronger contractions -positive feedback
oviducts
ends are fimbriae, collect eggs as they are released from ovaries. cilia then carry them down the oviducts toward the uterus
implantation
formation of embryonic membranes and placenta occurring if embryo arrives at the endometrium during the secretory phase
hormone control (female)
hypothalamus: GnRH→anterior pituitary: FSH + LH→ FSH: development of follicle + LH: ovulation, development of corpus luteum→follicle: estrogen + corpus luteum: progesterone→estrogen + progesterone exert negative feedback on hyp.
hormone control (male)
hypothalamus: gonadotropin-releasing hormone→anterior pituitary: follicle-stimulating hormone + luteinizing hormone→FSH: spermatogenesis + LH: secretion of testosterone→testosterone exerts negative feedback on hyp.
birth control
includes a mixture of estrogen and progesterone which artificially exerts negative feedback on hypothalamus, causing less GnRH, less LH (prevents normal ovulation)
endometrium
lining of the uterus -develops glands and a rich blood supply to form the placenta during pregnancy
uterus
muscular organ in which fetal development occurs
ovarian cycleo
occurs in ovaries in response to follicle-stimulating hormone and luteinizing hormone -follicular phase -luteal phase
uterine cycle
occurs in the uterus in response to estrogen and progesterone -proliferative phase -secretory phase
cervix
opening of the uterus
clitoris
organ of sexual arousal
penis
organ of sexual intercourse/arousal. contains erectile tissues, as well as the end of the urethra
ovary
paired female gonad, includes (at different times) -follicle -corpus luteum
testes
paired male gonad, includes -seminiferous tubules -interstitial cells -epididymis contained by scrotum
interstitial cells
secrete testosterone
path of sperm
seminiferous tubules→epididymis→ductus deferens→urethra→combine with other components of semen→out
epididymis
sperm mature and are stored until released here
seminiferous tubules
spermatogenesis occurs here
urethra
tube in which the components of semen are combined and carried out of the penis.
ductus deferens
tube which carries sperm from the epididymis to the urethra
follicular phase
-Days 1-14 -FSH causes follicle to form -follicle releases estrogen -FSH decreased by negative feedback -high estrogen temporarily exerts positive feedback -hypothalamus releases GnRH -brief surge in FSH + LH -surge in LH causes ovulation
proliferative phase
-Days 1-14 -progesterone + estrogen are low -endometrium breaks down -menstruation occurs -Day 6: estrogen levels increase (follicle) -endometrium thickens, develops glands & blood supply
secretory phase
-Days 14-28 -Day 14: ovulation -progesterone levels increase (C.L.) -endometrium doubles in thickness -glands secrete thick mucus -endometrium able to receive embryo -if no embryo arrives, progesterone levels decrease again -cycle restarts
luteal phase
-Days 14-28 -LH causes corpus luteum to form -corpus luteum secretes progesterone -if no embryo arrives, C.L. degenerates -progesterone + estrogen levels drop -cycle restarts
prostate gland
-basic fluid (neutralizes acidic vagina) -30% of semen
acrosome (sperm)
-cap covering head -contains enzymes for breaking into the egg
midpiece (sperm)
-contains mitochondria (energy)
head (sperm)
-contains nucleus
estrogen
-development of female reproductive anatomy -thickening of endometrium -development of breasts -broader hips -shorter legs
tail (sperm)
-flagellum
seminal vesicles
-fructose (nourishes sperm) -prostoglandins (stimulates uterine contractions) -60% of semen
progesterone
-further development of endometrium such that it can receive fertilized embryo
follicle
-hollow sac containing the egg during the first part of the menstrual cycle -secretes estrogen
human chorionic gonadotropin
-hormone released by embryonic membranes -prevents degeneration of C.L. -progesterone (& estrogen) levels maintained throughout pregnancy
testosterone
-male reproductive anatomy -broader shoulders -longer legs -body and facial hair -larger larynx -increased muscle development
sperm
-male reproductive cells, made up of head, acrosome, midpiece, and tail -5% of semen
Cowper's glands
-mucus (cleans urethra, lubricates intercourse) -5% of semen
corpus luteum
-outer lining of a follicle after egg is released -develops into thickened gland -secretes progesterone & a little bit of estrogen
vagina
-receives penis during intercourse -receives menstrual fluids -forms birth canal
