Describe the function of Anti-diuretic Hormone in the maintenance of a constant volume of water in the body.

Anti-diuretic Hormone (ADH) is secreted from the hypothalamus in the brain. If more ADH is produced, it makes the collecting ducts in the nephron of the kidneys, more permeable to water. Therefore, less water is re-absorbed back into the bloodstream resulting in diluted urine being produced and secreted from the body. On the other hand, if less ADH is secreted from the hypothalamus, the opposite happens; more water is re-absorbed back into the bloodstream resulting in concentrated urine being produced and secreted from the body.