Compare and contrasts the various means by which the body loses heat to, or gains heat from, the external environment

Question

What will be an ideal response?

Answer 1

There are four ways that the body can gain heat from or lose heat to the external environment. (1) Radiation is the transfer of heat in the form of waves that travel through space. If the skin is radiating more heat waves than it is absorbing, the body will lose heat. If more heat waves from an external source are being absorbed by the body than are being emitted, the body will gain heat. Vasoconstriction in the skin when the body temperature is dropping decreases the amount of radiant heat lost to the external environment. Vasodilation in the skin when the body temperature is rising increases the amount of radiant heat lost to the environment. (2) Conduction is the transfer of heat between two objects in direct contact, such as between the skin and any other substance, including air. The warmer substance will always gain heat from the cooler substance. The body making contact with warmer or cooler objects results in the gain or loss of heat. (3) Convection is the transfer of heat by currents of air or water. Even if the air is the same temperature as the skin, blowing the air over the skin will remove heat and cool the body. Using a fan to maintain "fresh air" in contact with the skin can increase the rate of heat gain or heat loss. (4) Evaporation involves the transfer of heat when water is converted from a liquid to a gas. Evaporation of sweat removes significant amounts of heat from the body.