Homeostasis in mammals involves physiological control systems that maintain the internal environment within restricted limits.

The importance of maintaining a stable core temperature and stable blood pH in relation to enzyme activity.

The importance of maintaining a stable blood glucose concentration in terms of availability of respiratory substrate and of the water potential of blood.

Negative feedback restores systems to their original level.

The possession of separate mechanisms involving negative feedback controls departures in different directions from the original state, giving a greater degree of control.

Students should be able to interpret information relating to examples of negative and positive feedback.