There is more than one system: 1. Kidneys Kidneys are bean-shaped. Once the body has extracted what it needs from food and drink, it sends the wastes to the kidneys. The kidneys filter the wastes, including urea, salt and excess water, which are flushed out of the body as urine. 2. Skin The skin performs its excretory function via the sweat glands. These glands produce sweat that contains salt, excess oils, water, and other unnecessary substances which are then excreted out of the body through small pores. 3. Lungs The lungs are very important excretory organs as they expel carbon dioxide from the body via exhalation. Otherwise, the carbon dioxide would accumulate and have a detrimental effect to our body. You can see that the effects of one is different than the other two. If you lost any one of these entirely you would die without medical help of some sort.