Unit B: Reproductive Hormones

Gonadotropic Releasing Hormone

• Stimulate hypothalamus to cause the anterior pituitary to release hormones

• Increase release of FSH and LH

Follicle Stimulating Hormone

Stimulates development of sex organs as well as the production of ova

Luteinizing Hormone

• Triggers ovulation

• Stimulates the production of estrogen

The Ovarian Cycle

Follicle will mature, releasing an ovum, which then develops into the corpus luteum which will then degenerate

Follicular Stage

• Increase in levels of FSH released by the anterior pituitary

• FSH stimulates one follicle to mature releasing estrogen and some progesterone

• Increased levels of estrogen will stop the release of FSH

• Estrogen also increases the release of GnRH from the hypothalamus leading to an increase of LH which triggers ovulation

Luteal Stage

• LH causes the follicle to develop into a corpus luteum

• This secretes estrogen and progesterone which acts on the hypothalamus to stop of the release of FSH and LH

• This will then degenerate

The Uterine Cycle

• First day of menstruation the corpus luteum has disintegrated

• Higher estrogen levels causes the endometrium to thicken

• After ovulation, progesterone levels causes the endometrium to thicken even more

Menopause

• End of menstrual cycle

• No longer producing ova = not fertile

FSH in Men

Stimulates the development of sex organs as well as the production of sperm

Inhibin

• Hormone that acts on the anterior pituitary to inhibit the production of FSH

LH in Men

Stimulates the production of testosterone

Testosterone

Acts on various tissues to complete the development of sex organs and sexual characteristics