Editing Excretory system (section)

{{Short description|Biological organ system that removes unnecessary materials from the body of an organism}}
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The '''excretory system''' is a passive biological system that removes excess, unnecessary materials from the [[body fluid]]s of an [[organism]], so as to help maintain internal chemical [[homeostasis]] and prevent damage to the body. The dual function of excretory systems is the elimination of the [[Cellular waste product|waste products]] of [[metabolism]] and to drain the body of used up and broken down components in a liquid and gaseous state. In humans and other [[amniote]]s ([[mammal]]s, [[bird]]s and [[reptile]]s), most of these substances leave the body as [[urine]] and to some degree exhalation, mammals also expel them through [[sweat]]ing.

Only the organs specifically used for the excretion are considered a part of the excretory system. In the narrow sense, the term refers to the [[urinary system]]. However, as excretion involves several functions that are only superficially related, it is not usually used in more formal classifications of anatomy or function.

As most healthy functioning [[organ (anatomy)|organs]] produce metabolic and other wastes, the entire organism depends on the function of the system. Breaking down of one of more of the systems is a serious health condition, for example [[kidney failure]].