Osmoregulation

• Osmoregulation= controlling the water potential of the blood.
• ADH is produced in the hypothalamus and stored in the pituitary gland.

  • Osmorecptors in hypothalamus detect changes in the water concentration of the blood and send electrical impulses to the pituitary gland to secrete more or less ADH.
  • Pituitary gland sends ADH to nephrons
• 1. ADH bind to receptors on cells of the collecting duct and triggers the formation of cAMP.
  2. cAMP causes vesicles to fuse with the membrane on the interstitial side of the cell.
  3. Vesicles contain aquaporins which are inserted into the cell surface membrane and make it permeable to water.
  4. Water moves out the cell into the tissue fluid.
  5. Now the cells have a low water potential inside so water from the lumen of the collecting duct moves into the cell by osmosis.