excretion

• excretion

  • is the removal of metabolic rate from the bodymetabolic waste is defined as a substance that is produced in excess as a result of metabolic processes in cells
  • egestion is the process of removing undigested food
  • important that these metabolic waste substances are removed before they become toxic
• • lungs: carbon dioxide
  • liver: urea, hydrogen peroxide, detoxification of drugs and alcohol
  • kidneys: urea
  • skin: urea, uric acid and ammonia
• lungs

  • removes carbon dioxide
  • result of respiration - pass from cells of respiring tissues into bloodstream where it is transported to lungs and changes PH
• liver

  • removes urea, alcohol and drugs, hydrogen peroxide
  • many metabolic roles and some of the substances produced passed into bile for excretion with faeces
• kidneys

  • urea
  • urea passed into bloodstream to be transported in solution - dissolved in plasma
• skin

  • uric acid, urea, ammonia
  • sweat contains range of substances including salts, urea water, uric acid and ammonia
  • loss of water and salts maintaining body temperature and water potential of blood