Temperature Regulation

Abstract

Normal body temperature is controlled by the regulation of heat production and heat loss. Two main regulating systems are recognized, with receptors in the skin and in the hypothalamus, though the interactions between these systems are still imperfectly understood. The efficiency of both systems can be tested. It is possible that noradrenaline and 5-hydroxytryptamine may play a part in the hypothalamic system, perhaps as chemical transmitters, though the evidence for this is equivocal. The cause of accidental hypothermia remains uncertain, though there is evidence that old people do not respond as effectively as young ones to cold environments. Chronic hypothermia may be due to a complete failure of the control-regulating mechanism, or it may merely represent the active regulation of body temperature at an abnormally low level. During fever body temperature is regulated as precisely as in health, but at a higher level. This is almost certainly brought about within the hypothalamus by endogenous pyrogen liberated from cells exposed to inflammatory processes. It is still unknown whether a febrile response confers any benefit upon the sick animal. © 1966, British Medical Journal Publishing Group. All rights reserved.