Excretory System

The excretory system is a passive biological mechanism that removes unnecessary materials from an organism’s body fluids in order to maintain internal chemical balance and protect the body from damage. Excretory systems serve two purposes: they eliminate metabolic waste products and drain the body of used up and broken down components in liquid and gaseous form. The bulk of these chemicals leave the body by urine and, to a lesser extent, exhalation in humans and other amniotes (mammals, birds, and reptiles); mammals also expel them through perspiration.

The excretory system includes the organs that are needed for excretion. It refers to the urinary system in its most basic sense. Excretion is not frequently included in more rigorous classifications of anatomy or function because it encompasses multiple functions that are only superficially connected.

The entire organism is dependent on the system’s function because most healthy functioning organs produce metabolic and other wastes. Kidney failure is a significant health condition caused by the breakdown of one or more of the systems.