Removal of waste products

• Cells of your body are constantly producing waste products
• Main poisonous waste products

  • CO₂
  • Urea
• They cause major problems if they build up in the body
• CO₂ removal


  1. Produced by body during respiration

  2. Dissolved CO₂ produces an acidic solution

  3. CO₂ diffuses out of cells into blood

  4. CO₂ diffuses from blood into air in alveoli of lungs

  5. CO₂ is removed when we exhale
• Urea removal


  1. Extra protein in body has to be broken down

  2. Amino acids cannot be stored in body

  3. Liver removes amino group from amino acids by deamination process

  4. Ammonia is formed and converted into nitrogenous waste - urea

  5. Urea is filtered out of blood by the kidneys and excreted in urine
• Removal of these waste products balances the concentration of water and mineral ions in your body fluids
• If cells of body lose/gain too much water by osmosis they don't function efficiently
• Ways water/minerals/urea are lost from body

  • Water leaves lungs when you exhale
  • Water/minerals/urea lost in sweat
  • Water/minerals/urea removed by body via the kidneys and excreted in urine