Hormonal control of reproduction

seminiferous tubules

produce sperm in the testes

interstitial cells

produce testosterone in the testes

prostate gland and seminal vesicles

secrete fluids that maintain the mobility and viability of the sperm.

oviduct

where ova are released to be fertilised by sperm

zygote

fertilized egg

pituitary gland

releases follicle stimulating hormone (FSH), luteinising hormone (LH) or interstitial cell stimulating hormone (ICSH)

hypothalamus

stimulates the pituitary with a releaser hormone

FSH (follicle stimulating hormone) in men

travels to the testes from the pituitary and promotes sperm production in the seminiferous tubules

ICSH

stimulates the production of testosterone in the interstitial cells

Testosterone

stimulates sperm production and activates the prostate gland and seminal vesicles.

high levels of testosterone

inhibits FSH and ICHS

negative feedback

A type of regulation that responds to a change in conditions by initiating responses that will counteract the change. Maintains a steady state.

FSH in women

stimulates the development of a follicle

The follicle surrounding the ova

produces oestrogen in the follicular phase.

Oestrogen

stimulates proliferation of the endometrium preparing it for implantation and stimulates a surge in the secretion of LH.

surge in LH caused by oestrogen

triggers ovulation

Ovulation

the release of an ovum from a follicle in the ovary which usually occurs around the mid-point of the menstrual cycle

Luteal phase

the follicle develops into a corpus luteum

corpus luteum

secretes progesterone.

Progesterone

promotes further development and vascularisation of the uterus in the luteal phase

The lack of LH caused by increased progesterone levels leads to

degeneration of the corpus luteum

a drop in progesterone levels caused by degeneration of the corpus luteum leads to

menstruation

If fertilisation does occur

the corpus luteum does not degenerate and progesterone levels remain high.