Control of water Content in the Blood-Osmoregulation
The ability of the kidney to increase or decrease water absorption in the tubules is controlled by the amount of antidiuretic hormone (ADH)circulating in the blood. This hormone increases the permeability of the distal tubule and the collecting duct to water. As a result, more water can be reabsorbed from the urine. Production of ADH is in turn regulated by receptor cells in the brain that monitor the concentration of blood, and by receptor in the heart that monitor blood volume.