Thermoregulation: How the Body Cools Itself in Hot Environments”

Thermoregulation: How the Body Cools Itself in Hot Environments”

What are the physiological changes that occur in the body when exposed to high temperatures?
Answer:

• Body responses to hot environment:
  • Heat is lost from the body in several ways.
    1. Convection:
       1. 15% of heat is lost from body to the air by convection.
       2. The air in immediate contact with the skin is warmed up and the heated molecules move away and cooler ones come in to take their place.
       3. These in turn are warmed and so the process goes on.
    2. Radiation:
       • 60% of heat is lost by means of radiation.
       • Heat is lost from the body to cooler objects at a distance.
    3. Conduction:
       • 3% of heat is lost from the surface of the body to other objects by conduction.
       • Heat is lost only when it is in contact with a cooler object.
    4. Evaporation:
       • 22% of heat is lost through evaporation of water.
         1. Insensible water loss.
            • It consists of
              1. Water lost from the skin.
                 • It consists of the passage of water by diffusion through the epidermis.
              2. Water lost from the lungs.
                 • On an average the water loss from the lungs is approx 300 ml/day.
         2. Painting.
            • It occurs only in animals.
         3. Sweating.
            • Exocrine sweat glands take part in thermal regulation.
            • When one litre of sweat is evaporated 580 Kcal heat is lost.