Homeostasis
Homeostasis is the maintenance of a relatively constant internal environment of the body, the extracellular fluid, and the cells within it. It is essential in maintaining a constant and stable condition of properties like pH, temperature, water, ion concentrations and blood glucose concentrations. Homeostasis can be in either a closed or open system. Failure to maintain homeostasis can result in illness or disease.
Silverthorn D., Johnson B., Ober W., Garrison C., Silverthorn A. (2009) Human Physiology an Integrated Approach, 5th edition, San Francisco: Pearson Benjamin Cummings