reproductive hormones

male reproductive hormoone

• testosterone

• steroid hormone

• secreted from testes

male testosterone age

• levels decrease with age

• peak is around 20s

• release levels drops greatly 50s and after

how is testosterone secreted?

• hypothalamus releases GnRH into anterior pituitary

• FSH and LH secreted by anterior pituitary

• FSH and LH travel to gonads: ovaries/testes

• LH stimulates leydig cells

• leydig cells secrete androgen (testosterone) which causes primary and secondary sex characteristics

• FSH and testosterone stimulates sertoli cells

• sertoli cells cause spermatogenesis; sperm production

primary and secondary sex characteristics

• primary: reproductive organs; testes, penis, ovaries, uterus, vagina

• secondary: during puberty; deeper voice, facial and body hair, increased muscle mass (men), breast development, hip widening, body fat redistribution (women)

androgen and negative feedback

• high levels of androgens - testosterone

• signal anterior pituitary to decrease production of LH and FSH

• signal hypothalamus to decrease production of GnRH

androgens

• class of hormones

• present in men and women

• testosterone

ovaries

• female reproductive system

• produce gametes

• produce estrogen

• produce progesterone

estrogen

• produced by ovaries

• stimulates and controls reproductive system

• prepares and maintains uterus for implantation

trouble getting pregnant/miscarragies linked to

low levels of progesterone

fertilization

• after ovulation

• fertilization occurs: zygote travels and implants in uterus

• no fertilization: corpus luteum gradually shrinks, inhibits estrogen and progesterone secretion, egg degenerates → menstruation

ovarian cycle: follicular phase

• days 0-13

• release of GnRH by hypothalamus

• causes pituitary to release FSH and LH

• stimulates release of estrogen

sperm can last in a womans body for

5 days

ovulation

• day 14

• LH, FSH, estrogen causes monthly release of one or few developing eggs/oocytes

• 24 hour period of fertility

• LH and FSH peak

luteal phase

• day 15-28

• estrogen decreases, progesterone rises

• LH causes follicle to form corpus luteum: mass of cells that secretes progesterone

• progesterone causes lining of uterus to thicken for egg to implant and zygote to grow

corpus luteum secretions

• estrogen

• progesterone

• inhibin

follicular phase

• begins with period

• ends with ovulation

• mature egg released

• estrogen increases most

• inhibin increases slightly

• FSH and LH peak

• lower body temp

luteal phase characteristics

• starts after ovulation

• ends when period begins

• corpus luteum forms

• FSH and LH drop

• estrogen drops

• progesterone increases most

• inhibin increases

• higher body temp

what hromone slows LH?

progesterone