Short—Term Regulation in Various Environments: Inputs and Responses

Abstract

Chapter 12 dealt with the relationships between major deviations in core and skin temperatures (T_core, T_skin) and the resultant changes in heat production (HP) or evaporative heat loss (EHL). However, animals are not permanently either shivering or sweating: within a range of intermediate temperatures, body temperature is regulated by adjustments of skin blood flow that modify dry heat loss, while the large and costly defence mechanisms against cold or heat are inactive. Figure 14.1 is adapted from Fig. 12.4 and is based on results of a study in a human subject dressed in shorts. The threshold combinations of T _core and T _skin , at which HP or EHL departed from their minima, encompass a zone in which regulation was achieved only by vasomotor control. Its width was as narrow as 0.25 °C for T_core, and 3.5 °C for T_skin. Comparable observations were made in goat [258].