The Maintenance of a Constant Internal Environment

Abstract

All the systems of the body, if they are to function effectively, must be subjected to some form of control. Food intake must be controlled by employing the device of appetite, otherwise too much or too little food would be eaten. The breathing rate must be controlled so that oxygen can be supplied and carbon dioxide removed at precisely the right rate. The working of the kidney must be controlled so that water and waste materials are removed neither too slowly nor too quickly.