Properties of central control of body temperature in the rabbit

Abstract

The structure of the central temperature controller in rabbits has been analysed. On the one hand, experiments were carried out to obtain the necessary data for system analysis; on the other hand, a mathematical model of the passive system was developed which describes the thermal characteristics of the body in accordance with the experimental results. In applying the model, different controller equations for the effector mechanisms involved were tested to fit the experimental data best. They are compared with already existing models of metabolic control. In addition, mechanisms of the effector coordination are discussed. It is shown that the three effectors make use of a similar controller structure that feeds core temperature as well as skin temperature back into the controller. The system is insensitive to variations of the controller gains, whereas a slight change in the controller reference temperature causes significant changes of the controlled core temperature. Furthermore it is shown that any mutual effector blockings are dispensible.

Control of metabolic rate is a hidden variable in the allometric scaling of homeotherms

“…This organ receives and integrates information from peripheral and core temperature sensors and modulates a number of responses, including motor outputs modifying metabolic rate (shivering and non-shivering processes) and changes in the thermal conductance through skin and peripheral blood flow, fur/feather positioning, etc (Graener et al, 1984;Gordon, 1986;Boulant, 2000;Cooper, 2002). Empirical evidence to date indicates that the control law is proportional to the error between T b and a reference temperature (Graener et al, 1984;Gordon, 1986;Webb, 1995;Hexamer and Werner, 1996;Boulant, 2000;Cooper, 2002). Fig.·2A illustrates the biological basis of the process described above.…”