2.78B: Describe the Role of ADH in Regulating the Water Content of the Blood

ANTIDIURETIC HORMONE (ADH): Hormone produced by Hypothalamus and stored/secreted by Pituitary gland to control water content of blood via reabsorption of Water at Collecting Duct

LOW LEVELS OF WATER	HIGH LEVELS OF WATER
Diagram Showing Osmoregulation when Water Levels in the Body is Low	Diagram Showing Osmoregulation when Water Levels in the Body is High
Hypothalamus detects low levels of Water in body, stimulating Pituitary gland to secrete more ADH Increase in ADH causes membrane of Collecting Duct to become more permeable with the increase in pores, therefore increasing the reabsorption of Water into blood capillaries via Osmosis As more Water is reabsorbed, Water levels in the body is regulated and returned to normal As a result, volume of Urine will decrease and become more concentrated	Hypothalamus detects high levels of water in body, stimulating Pituitary gland to secrete less ADH Decrease in ADH causes membrane of Collecting Duct to become less permeable with the decrease in pores, therefore preventing the reabsorption of Water into blood capillaries As less Water is reabsorbed, Water levels in the body is regulated and returned to normal As a result, volume of urine will increase and become less concentrated (more diluted)