Notes

The endocrine system is a second coordination and control system made up of glands secreting hormones directly into the blood, carrying it to the target organs, where it takes effect by triggering a response in the cell when the receptors on the cell membrane pick up the hormone. Hormonal effects are slower but longer-lasting than the nervous system.

The pituitary gland secretes a variety of different hormones into the blood in response to changes in body conditions: ADH, which affects the amount of urine made by the kidney; FSH, which stimulates the ovaries to make oestrogen; and TSH, which stimulates the thyroid to make thyroxine controlling metabolic rate. The pituitary gland also makes growth hormone and stimulates the testes to make sperm and testerone.

The pancreas control blood glucose levels, the adrenal glands prepare the body for stressful situations, the ovaries control the development of the female secondary sexual characteristics and is involved in the menstrual cycle; and the testes control the development of the male secondary sexual characteristics and is involved in the production of sperm.