Homeostasis is highly developed in warm-blooded animals living on land, which must maintain body temperature, fluid balance, blood pH, and oxygen tension within rather narrow limits while at the same time obtaining nutrition to provide the energy to maintain homeostasis. This is because maintaining homeostasis requires the expenditure of energy. Energy is used for locomotion as the animal seeks and consumes food and water, for maintaining body temperature via the controlled release of calories from the metabolism of food or fat stores, and for sustaining cell membrane function as it resorbs electrolytes in the kidney and intestine and maintains neutral blood pH. © 2007 Copyright © 2007 Elsevier Inc. All rights reserved.
McEwen, B. S. (2010). Homeostasis. In Encyclopedia of Stress (pp. 347–348). Elsevier Inc. https://doi.org/10.1016/B978-012373947-6.00200-2