The Excretory System removes excess of water, salts & carbon dioxide.
Excretion refers to the removal of wastes from the body. The excretory organs of our body include the kidneys, skin and the lungs. Kidneys play an important role in the removal of nitrogenous wastes, water and salts in the form of urine. Skin is alos involved in the removal of salts and water.
Lungs play an important role in the removal of excess of carbon dioxide from the blood. Carbon dioxide is a byproduct of oxidation of glucose in the body and it has to be removed from the blood. Excess of carbon dioxide in the blood changes the pH of the blood and is toxic to the body. Thus, alveoli of the lungs are involved in expelling the carbon dioxide from the blood.