2.89

2.89 understand the sources, roles and effects of the following hormones: ADH, adrenaline, insulin, testosterone, progesterone and oestrogen.

ADH: The pituitary gland produces ADH, anti-diuretic hormone. It causes the kidney tubules to reabsorb more water into the blood.

Adrenaline: The adrenal glands produce adrenaline. This is released in times of excitement, anger, fright or stress, and prepares the body for a fight. The effects are increased heart rate, increased depth of breathing and breathing rate, increased sweating, hair standing on end (making furry animals look larger), glucose released from liver and muscles, dilated pupils and finally, paling of the skin as blood is redirected to muscles.

Insulin: The pancreas secretes insulin and glucagon. Insulin controls the level of glucose in the blood and it helps maintain a steady blood glucose level. Glucagon has the opposite effect of insulin where stored glycogen (stored in the liver) is converted into glucose and released into the blood. People with diabetes mellitus cannot make enough hormone insulin.

Testosterone: It is secreted from the testes. Testosterones cause secondary sexual characteristics in boys.

Progesterone: The ovaries produce progesterone. It combined with oestrogen controls the menstrual cycle.

Oestrogen: The pituitary gland produces FSH, which controls oestrogen production in the ovaries. The ovaries produce oestrogen. It is responsible for the development of secondary sexual characteristics in girls.