CENTRAL AND PERIPHERAL MECHANISMS IN 
TEMPERATURE REGULATION 
Thomas P. K. Lim 
Lovelace Foundation 
Albuquerque, New Mexico 
One of the outstanding characteristics of the mammalian 
body is its chemical and physical control mechanisms by which a 
constancy of internal environment is maintained. The behaviors 
of hemodynamics, gas exchange, electrolyte balance, energy trans- 
fer, and hormonal interaction clearly indicate that their ultimate 
goals are in preserving an optimum intrinsic condition which allows 
harmonious and efficient performance of complex processes. The 
regulatory phenomena of body temperature are no exception from 
this general premise. 
The understanding of temperature control has been greatly 
facilitated by the establishment of two cardinal neural mechanisms, 
namely, the major control elements located centrally in the hypo- 
thalamus which Dr. Hemingway described this morning, and the 
temperature sensing elements found peripherally in the skin, which 
Dr. Hensel described this afternoon. It is agreed that the central 
control mechanism may be subdivided into a motor unit which 
primarily governs heat dissipation and another which controls heat 
conservation. Furthermore, it is accepted that the peripheral 
thermoreceptors consist of two anatomical or electrophysiological 
units, that is, the receptors for cold and those for warmth, in the 
sense of functional anatomical units. 
Although the existence of temperature-sensing elements in the 
hypothalamus has never been demonstrated, it may be assumed 
that such receptors exist in the vicinity of the motor units of heat 
dissipation and conservation. Therefore, an hypothesis is advanced 
allowing functional elements of temperature detection in the hypo- 
thalamus as they exist in the skin. Then, central control is believed 
to depend upon thermoreceptors located in the hypothalamus, so 
that the relevant "central temperature" is that of the hypothalamus 
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