The excretory system is a passive biological system that removes excess, unnecessary materials from an organism, so as to help maintain homeostasis within the organism and prevent damage to the body. It is responsible for the elimination of the waste products of metabolism as well as other liquid and gaseous wastes, as urine and as a component of sweat and exhalation. As most healthy functioning organs produce metabolic and other wastes, the entire organism depends on the function of the system; however, only the organs specifically for the excretion process are considered a part of the excretory system. As it involves several functions that are only superficially related, it is not usually used in more formal classifications of anatomy or function.
Contributions by Spaully, 184.108.40.206, and Kusb.