Keep volume of water in body constant - Function of Kidney

Keep the volume of water in the body constant by removing excess fluid from the body. The kidneys regulate the volume of extra-cellular fluid by eliminating or retaining water. The re-absorption of water in the tubules is controlled by pituitary and hypothalamic actions. The posterior pituitary produces anti-diuretic hormone (ADH), which increases the amount of water reabsorbed, the adrenal cortex (another endocrine gland) produces the hormone aldosterone, which influences the re-absorption of sodium and water.