kidneys regulate water potential of blood

• Loss of water through sweat

  • Water potential decreases below normal
  • stimulate hypothalamus to stimulate pituitary gland to release more antidiuretic hormone into bloodstream
  • cells in walls of collecting duct and distal convoluted tubule become more permeable and more water reabsorbed
  • smaller volume of urine produced and more concentrated
  • w.p increase back to normal
• Excess water through drinking too much water

  • water potential increases above normal
  • stimulate hypothalamus in brain to stimulate pituitary gland to release less ADH into bloodstream
  • cells in CD and DCT are less permeable so less water is reabsorbed
  • larger volume of urine produced, less concentrated
  • w.p decreases back to normal