Answer
The preoptic nucleus hypothalamus is the thermostat of the body. It monitors the temperature of the blood and the periphery of the body, and regulates body temperature around the set point by feedback signals sent from the heat loss center and the heat promoting center.
If the body temperature is too high the following mechanisms are employed to maintain and generate heat and minimize heat loss.
a. Stimuli are sent from the heat loss center that cause vasodilation and the routing of more blood to the cutaneous circulation. This facilitates loss of heat from the surface of the skin by conduction and radiation, and by convection.
b. If the heat loss is not enough to bring the temperature down within normal limits , the heat loss center triggers sweating. As sweat evaporates much more heat is lost.
In the opposite condition where the body temperature has fallen too low, the heat promotion center acts in the following ways to preserve or generate body heat:
a. Through the agency of the sympathetic sympathetic nervous system the blood vessels are stimulated to constrict. This keeps much of the warm blood in the important core organs and away from the periphery. As a consequence the core is kept warm and heat loss from the periphery is curtailed.
b. Thermogenic shivering is another mechanism used to keep the body warm. This process involves the alternate contracting of pairs of small antagonistic muscles-- a process that involves a spinal reflex response to the fall in body temperature.
Work Step by Step
Muscle contraction involves release of energy and heat from ATP.
