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