NEGATIVE FEEDBACK

• DESCRIBE HOW THE WATER CONTENT IN THE BLOOD IS CONTROLLED: (6)

  • If there is too LITTLE water in the BLOOD, this is DETECTED by the HYPOTHALAMUS in the BRAIN.
  • Therefore more of the ADH hormone (ANTIDIURETIC) is is released into the BLOOD by the PITUITARY gland
  • The kidneys ABSORB less WATER from the blood, so less WATER is lost in URINE ( which is more DILUTE)
  • Then, the blood WATER level returns to NORMAL
• WHAT HAPPENS IF THE WATER LEVELS ARE TOO LOW?

  • HYPOTHALAMUS in brain DETECTS the concentration of WATER in the BLOODSTREAM
  • WATER levels are too LOW- sends a SIGNAL to PITUITARY gland (in FRONT of BRAIN, behind EYES
  • PITUITARY gland- released ADH into the BLOODSTREAM
  • ADH- travels around the BODY and reaches the KIDNEYS (MORE water is ABSORBED)
  • Amount of WATER in the BLOODSTREAM then INCREASES (less URINE produced)