water levels

• What does the body do when the water levels are too low?

  • Hypothalamus detects it.
  • More ADH is released from the pituitary gland.
  • There is an increased permeability of the kidney tubules
  • More water is reabsorbed in the blood.
  • The water level rises.
• What does urine look like when water levels are low and why?

  • More concentrated.
  • Because less water stays in tubules.
• What does the body do when the water levels are too high?

  • Hypothamulus detects it.
  • Less/no ADH is released from the pituitary gland
  • Decreased permeability of kidney tubules
  • Less water is reabsorbed in the blood
  • Water levels fall
• What does urine look like when water levels are too high?

  • Lots of dilute urine
  • Because more water stays in the tubules.
• What is ADH?


  A hormone that regulates the amount of water in the body.
• Why is urea generated?

  • The digestion of proteins leaves excess amino acids
  • The liver deaminates amino acids to form ammonia (toxic)
  • Ammonia is converted to urea to be safe for excretion
  • Urea is less toxic than ammonia
• What is deamination?


  The removal of an amine group.
• What is excretion?


  The removal of waste products made in the body.
• How do the kidney's produce urine?

  • Blood entering the kidneys is filtered.
  • The kidney's use selective reabsorption
  • Urine contains what is left in the kidneys tubule.
• What is selective reabsorption?

  Only reabsorbing useful molecules back into the blood. For example, glucose.
• How is the kidney filtered?

  Only small molecules can pass through the membrane into the kidney tubule and large molecules remain in the blood.