QS Study

Body temperature is the property of the body that determines whether or not the body is in thermal equilibrium with the environment. The body is very good at keeping its temperature within a safe range, even when temperatures outside the body change a lot. The temperature of the body is regulated by neural feedback mechanisms which operate primarily through the hypothalamus. The hypothalamus contains not only the control mechanisms but also the key temperature sensors.

Fig: Heat Production mechanism of our body

Mechanism of heat production – Heat is a byproduct of the cellular oxidations that produce energy. The amount of heat produced by a given organ varies with the kind of tissue and its activity. The brain produces only 15% of body heat at rest, and an increase in nervous tissue activity produces little increase in heat production.

  • Basal metabolic rate (BMR) of all cells of the body.
  • Muscular activity caused by shivering.
  • Effect of thyroxine, growth hormone, testosterone.
  • Effect of epinephrine, norepinephrine and sympathetic activity.
  • Food intake (Specific dynamic action).
  • Increased chemical activity in the cells.

The body has an excellent heat-regulating mechanism, which under normal conditions can adjust its temperature to sustain the proper heat balance. More than 80% of heat loss occurs through the skin. The remaining 15% to 20% is dissipated by the respiratory system and with the urine and feces.