One mechanism that involves the blood supply that can be utilized by some animals to limit heat loss in cold environments is
A)vasodilation of the near surface blood vessels.
B)vasodilation of below surface blood vessels.
C)vasoconstriction of the precapillary sphincters in the skin.
D)vasoconstriction of veins.
E)increasing cardiac output.

Question

Quizplus · Accepted Answer

Vasoconstriction of the precapillary sphincters in the skin reduces blood flow to the surface, thereby limiting heat loss from the body. This mechanism is used by some animals, such as mammals and birds, to maintain their body temperature in cold environments. By reducing blood flow to the skin, these animals are able to conserve heat and maintain a warm core temperature. Vasodilation of the blood vessels, either near or below the surface, would have the opposite effect, increasing heat loss through the skin. Increasing cardiac output also does not directly affect blood flow to the skin and would not be an effective mechanism for limiting heat loss. Vasoconstriction of veins could help to maintain blood pressure but would not necessarily have an effect on heat loss.

One Mechanism That Involves the Blood Supply That Can Be