Question

Explain the terms vasodilation and vasoconstriction. How does this process contribute to the temperature regulation of the body?

Answer 1

Human is a mammal and it can maintain its body temperature. Likewise, Birds can also maintain their body temperature. On the other hand, reptiles are cold-blooded animals that cannot regulate their body temperature.

Complete answer:
The regulation of body temperature is called thermoregulation. The birds and mammals are endotherms, as they maintain their body temperature at the expense of their metabolic energy. Other animals are ectotherms, like lizards and snakes cannot maintain temperature by their metabolic energy rather they absorb heat from the environment to maintain their body temperature.
The temperature of the human body is maintained by different mechanisms like-
-The layer of fat present below the skin acts as the heat-insulating layer that keeps us and other mammals warm.
-Some animals have longhairs over their body in cold areas like yak that maintain the body temperature.
-Sweating also reduces body temperature in humans and animals.
-Circulatory Mechanisms - It includes vasodilation and vasoconstriction.
-Vasodilation: in this method, the blood vessels are dilated by increasing the diameter of the blood vessels. In the endotherms, when more heat is generated in the body, the blood vessels are dilated that increases the rate of blood flow from inside the body to skin and animals lose their extra heat into the nearby environment through the skin.
-Vasoconstriction: in this method, the vessels get contracted due to the effect of hormones, pressure etc. and their diameter is reduced. In endotherms, it reduces the loss of heat or metabolic energy (heat retention) in the environment by reducing the blood flow towards the skin due to the shrinkage of blood vessels.

Note: These mechanisms maintain the body temperature in animals as well as in humans. Although humans wear cloth to maintain their body temperature, these mechanisms are more useful for animals.