Identification

• The kidneys, liver, lower intestines, lungs and skin are the organs of the excretory system.
  
  

Function

• The four functions of the excretory system, according to ThinkQuest.org, are to get rid of wastes, eliminate useless byproducts excreted from cells, eradicate harmful chemical buildups and maintain a steady, balanced chemical concentration in the body.
  
  

Significance

• According to AGC United Learning's Human Body Systems Series, "if wastes build up, they can poison the body. They can also prevent oxygen and food from entering the cells. These wastes include carbon dioxide, urea, nitrogen, inorganic salt and heat."
  
  

Kidneys And Intestines

• The kidneys eliminate all liquid wastes, or urine, from the body, while the intestines remove the solid wastes.
  
  

Liver

• The liver produces bile needed for breaking down fats.
  
  

Skin And Lungs

• The skin keeps the body cool by excreting sweat, while the lungs remove carbon dioxide from the body while supplying it with the necessary oxygen to survive.