Question

Explain the terms “vasodilation” and “vasoconst- riction”. How do these processes contribute in the regulation of the body temperature?



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Answer 1

Explanation:

Blood vessels supplying blood to the skin can swell or dilate - vasodilation. This causes more heat to be carried by the blood to the skin, where it can be lost to the air. Blood vessels can shrink down again - vasoconstriction. This reduces heat loss through the skin once the body's temperature has returned to normal.

Answer 2

Vasodilation refers to the dilation of blood vessels. Vasoconstriction refers to the narrowing of blood vessels.

Explanation:

• Vasodilation is the dilation of blood vessels in the skin, which results in an increase in blood supply.
• Vasoconstriction is the narrowing of blood vessels, which reduces blood supply to the skin.
• In Cold Weather — When the temperature drops, blood vessels constrict. The blood supply to the skin is reduce.
• As a result, there is less heat loss through convection, conduction, and radiation, as well as less heat loss through vaporisation of sweat, because the sweat gland secretes less sweat when blood supply is reduced.
• In Hot Weather the outside temperature is high, there is vasodilation, which results in greater heat loss through radiation, etc., as well as vaporisation of sweat, which is now produced in greater quantities due to the rich blood-to-skin system.
• Air movements over the body aid in the evaporation of sweat, resulting in a cooling effect on our bodies.