AP BIOLOGY

Detailed explanation-1: -Too hot. When we get too hot, sweat glands in the skin release more sweat. The sweat evaporates, transferring heat energy from the skin to the environment. Blood vessels leading to the skin capillaries become wider-they dilate-allowing more blood to flow through the skin and more heat to be lost to the environment.

Detailed explanation-2: -Vasodilation cools the body by increasing heat loss from the blood vessels of the skin.

Detailed explanation-3: -When the sweat evaporates from the skin surface, the body is cooled as body heat is dissipated. In addition to sweating, arterioles in the dermis dilate so that excess heat carried by the blood can dissipate through the skin and into the surrounding environment (Figure 1).

Detailed explanation-4: -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.