Homeostasis

1. Dynamic self-regulation (involving periodicity), namely the ability of a system to maintain its fundamental, internal balances even while undergoing various processes of change.

2. The regulating system which determines the homeostasis of a particular feature may comprise a number of cooperating factors brought into action at the same time or successively. If a state remains steady, it does so because any tendency toward change is automatically met by increased effectiveness of the factor or factors which resist change. When a factor is known that can shift a homeostatic state in one direction, it is reasonable to look for automatic control of that factor or for a factor or factors which act in the opposite direction.

3. A tendency toward maintenance of a relatively stable internal environment in organisms, in organizations, and in individuals (i.e. the psychological condition), with respect to changing external environmental conditions, and the processes of growth and decay.

4. A property of all systems that maintain critical variables within limits acceptable to their own structure in the face of unexpected disturbance.