T17 Male Reproductive Physiology

GnRH - source

hypothalamus

GnRH - function

stimulates FSH and LH

low GnRH

decreased sperm production

FSH - source

anterior pituitary

FSH - function

stimulates Sertoli cells for sperm maturation

FSH - inhibited by

inhibin

low FSH

decreased sperm production

LH - source

anterior pituitary

LH - function

stimulates Leydig cells to produce testosterone

LH - inhibited by

testosterone

low LH

decreased testosterone, infertile

Testosterone - source

Leydig cells

Testosterone - function

maintains male secondary sex characteristics, supports spermatogenesis

Testosterone - inhibits what

GnRH and LH secretion

low testosterone

infertile, decreased libido

Inhibin - source

Sertoli cells

Inhibin - function

inhibits FSH secretion

Sperm transport - pathway

seminiferous tubules > rete testis > efferent ductules > epididymis > vas deferens > ejaculatory duct > urethra

Seminal vesicles - function

secrete fructose, PG, ascorbic acid, calcium for nutrients, peristalasis, sperm motility

Prostate gland - function

secretes clotting enzyme, zinc, buffers for nutrients, neutralization of acidic vagina

Bulbourethral glands - function

secrete mucus for lubrication and pH neutralization

site of spermatogenesis

seminiferous tubules

testosterone secreted when

in newborn, after puberty

testosterone - formation

LH > cholesterol desmolase > testosterone > 5 alpha-reductase > dihydrotestosterone

sperm capacitation

remove seminal plasma protein coating, increase membrane fluidity, increase motility

mechanisms to regulate temperature for spermatogenesis

pampiniform plexus, cremasteric muscle

estrogen - source in male

sertoli cell (testes)

estrogen - function in male

spermiogenesis, sperm maturation

growth hormone - source

anterior pituitary

growth hormone - function in male

metabolism, sperm development

inhibin - source in male

sertoli cell (testes)

inhibin - inhibits what

FSH to prevent excess production of sperms

activin - source in male

sertoli cell (testes), pituitary

activin - activates what

FSH for spermatogenesis

fetal hormone changes

MIF to inhibit mullerian duct development

childhood hormone changes

LH and testosterone levels drop

puberty hormone changes

LH and testosterone increase

adult hormone changes

LH > testosterone

aging adult hormone changes

testosterone and inhibin levels drop > increased LH and FSH