Testosterone

functions of testosterone

• essential for development of primary sex organs

• essential for development of sperm

• spermatogenic cells take up testosterone which stimulate their actvity

• increase testosterone concentration at puberty causes maturation of penis and testes

secondary sex characteristics of testosterone

• armpit hair

• pubic hair

• oil and sweat

• gland secrete more causing body odour

• larynx expands causing voice changes

• increased muscular strength

• sex drive

• facial hair

side effect of testosterone

baldness - genetically predisposed

hormonal control of testosterone

• hypothalamus releases GnRH (gonadotropic releasing hormone)

• GnRH causes anterioir pituitary to release 2 gonadotropic hormones

FSH

• follicle stimulating hormones

• promotes spermatogenesis in the seminiferous tubules

LH

• leutenizing hormone

• promotes production of testosterone in interstitial cells

negative feed back with testosterone

• increases in testosterone concentration in blood causes the anterior pituitary to make less LH and less testosterone is produced

• decrease testosterone concentration in blood causes the anterior pituitary to make more LH and therefore production of sperm decreases and stored concentration decreases causes a decrease in production of inhibin and more FSH, so more sperm is produced