Kidneys

• We lose water when we exhale
• we lose water, ions and urea through the skin when we sweat
• we lose water through the kidneys in urine
• 1. Blood enters the kidneys through the arteries. this blood contains urea, excess ions and water
  2. these leave the kidneys as urine in the bladder
  3. This new blood leaves the kidney through a vein containing No urea
  4. this blood passes through capillaries.urea, ions, water and glucose are passed into the blood
  5. all glucose some ions and some water is reabsorbed back into the blood. selective reabsorption.
  6. urea, excess ions, water and leave the body as urine
• when we digest too much protein the liver breaks down the amino acids and produce the chemical ammonia. this is called deamination. ammonia is toxic and the liver converts it into urea to be safely excreted by the kidneys