L2 - ADH: Hormone to Regulate Water Levels in the Blood

• ADH is a hormone that is produced in the pituitary gland. It travels in the blood to the kidney and causes the collecting duct walls to become more permeable to water.
• If the water levels in the blood are too LOW:

  • Receptor in pituitary gland in brain detects that there's too little water in the blood
  • Brain releases more ADH into blood
  • ADH enters kidneys and makes the collecting duct walls more permeable to water so more water is reabsorbed into blood
  • Blood water levels return to normal through negative feedback
  • Urine produced has a small volume and is more concentrated
• If the water levels in the blood are too HIGH:

  • Receptor in pituitary gland in brain detects that there's too much water in the blood
  • Brain releases less ADH into blood
  • ADH enters kidneys and makes the collecting duct walls less permeable to water so less water is reabsorbed into blood
  • Blood water levels return to normal through negative feedback
  • Urine produced has a larger volume and is less concentrated/dilute