How does skin cool the body?
Dermal blood vessels dilate, providing increased blood flow through the region and wisking away heat
Hypodermal cells can be consumed or created to conserve or liberate heat
Dermal blood vessels dilate, allowing heat to be absorbed by sweat, which evaporates
Dermal blood vessels constrict, providing less heat to the surface of the skin, keeping it cool
The correct answer and explanation is :
The correct answer is:
“Dermal blood vessels dilate, providing increased blood flow through the region and whisking away heat.”
Explanation:
The skin plays a crucial role in thermoregulation, helping the body maintain a stable internal temperature. One of the primary ways the skin cools the body is through the dilation of dermal blood vessels, a process known as vasodilation.
How Vasodilation Cools the Body:
When the body becomes too warm, the hypothalamus, which regulates temperature, signals the blood vessels in the dermis to expand. This increases blood flow to the skin’s surface, where heat is released into the surrounding environment. Since blood carries heat from the core of the body, moving it to the skin allows excess warmth to dissipate.
The Role of Sweat:
Along with vasodilation, the sweat glands become more active. As sweat is released onto the skin, it absorbs heat. When the sweat evaporates, it removes this heat, further cooling the body.
Why Other Options Are Incorrect:
- “Hypodermal cells can be consumed or created to conserve or liberate heat” – The hypodermis contains fat cells that insulate the body but does not play a direct role in cooling.
- “Dermal blood vessels dilate, allowing heat to be absorbed by sweat, which evaporates” – Heat is lost directly from the skin, not absorbed into sweat. Sweat simply facilitates cooling through evaporation.
- “Dermal blood vessels constrict, providing less heat to the surface of the skin, keeping it cool” – Constriction (vasoconstriction) occurs in cold environments to retain heat, not release it.
Thus, vasodilation and sweating are the body’s primary mechanisms for cooling.