Waste matter is made by every cell in your body. In some way, your body must get rid of all these wastes. Removing wastes from your body is the job of the excretory system.
Some waste is taken out of your body by the kidneys. The kidneys are two organs shaped like beans, each about the size of your fist. They are found near your waist, on each side of the backbone. The kidneys remove waste from the blood. This waste leaves your body in a liquid called urine.
Liquid waste can leave your body in another way. Whenever you have exercised a lot, you may have notices some sweat on your skin. As it evaporates on the surface of your body, your body cools. In this way, sweat helps your body cool down whenever it becomes too hot.
Pores allow sweat to leave the body. The liquid passes out through your pores even when you aren’t exercising. About a liter of water passes out through your pores each day! Yet only small amounts of wastes are found in this liquid.
The parts of the food you can’t digest move to the lower part of the large intestine. These wastes leave the body through an opening at the end of the large intestine.
Carbon dioxide is another kind of waste matter that is made in your cells. Your circulatory system carries it to your lungs, and your respiratory system sends it out of your body. Each time you breathe, your body gets rid of some of this gas.