Homeostasis - GCSE Biology Definition

What is homeostasis?

In GCSE biology, homeostasis is the maintenance of a constant internal environment. Internal conditions are maintained within narrow limits despite any changes in the external environment. Homeostatic mechanisms inside the body act to reverse any change from an ideal set point, ensuring that conditions remain constant, e.g. core body temperature must be kept at the optimum temperature for enzyme function.

Internal conditions are regulated by the nervous system and the action of hormones.  Examples of homeostasis include blood glucose regulation, temperature regulation (thermoregulation) and the regulation of blood water content (osmoregulation).