Question

In human body temperature control system, the command input is:

1. Temperature of the surroundings
2. Initial temperature of the body
3. Desired skin temperature
4. Actual skin temperature

Answer 1

Correct Answer - Option 2 : Initial temperature of the body

Human Body Temperature Control System:

The body regulates its temperature continuously. It may increase or decrease its temperature when it finds that it is too cold or too hot.

The temperature is being regulated by a control system, and the control is called homeostasis. Somewhere in the brain, perhaps the Hypothalamus, the optimum or initial temperature of the body (set point) is stored (about 37°C).

That information is continuously available to some structure, which we call the comparator. The comparator sends signals to:

1. Heat gain mechanisms in the pre-optic area or anterior hypothalamus leading to:
   • Shivering
   • Increased thyroid hormone output
   • Increased activity in the sympathetic nervous system
   • Piloerection
   • Cutaneous vasoconstriction
      
2. Heat loss mechanisms in the posterior hypothalamus leading to:
   • Decreased thyroid hormone output
   • Sweating
   • Cutaneous vasodilation

The output of these mechanisms will end as either a net increase or a net decrease in body temperature. The body temperature is sensed by thermal receptors (thermo-receptors) in the brain and peripherally in the body, and the value is sent to the comparator where it is compared with the set point.