osmoregulation

Process whereby the water content of living organisms is maintained at a constant level. If the water balance is disrupted, the concentration of salts will be too high or too low, and vital functions, such as nerve conduction, will be adversely affected.

In mammals, loss of water by evaporation is counteracted by increased intake and by mechanisms in the kidneys that enhance the rate at which water is reabsorbed into the blood before urine production. Both these responses are mediated by hormones, primarily those of the adrenal cortex (see adrenal gland).