Figure 3.
Compensatory activation. One advantage of multiple effectors is compensatory activation of alternative effectors if one effector fails, enabling control of the monitored variable. For instance, thyroidectomy augments sympathetic nervous system (SNS) responses to cold exposure. The left panel illustrates that in a homeostatic system involving two effectors (Eff. 1 and Eff. 2), inactivation of one effector leads to activation of the other. The right panel illustrates that in the homeostatic system for core temperature (Core Temp.) regulation, inactivation of the thyroid (THY) effector compensatorily activates the SNS effector.