dehydration

• osmoreceptor cels in the hypothalamus shrink stimulating the pituitary gland to secrete antidiuretic hormone which travels through the blood to the collecting duct where it binds to receptors causing vesicles to bind to the walls creating aquaporins
• ADH binds to receptors on the collecting duct walls causing a cascade of enzyme reactions. aquaporins are inserted into the membranes of the collecting duct epithelial by vesicles binding to them. water diffuses down a water potential gradient out of the urine in the collecting duct to the blood