GENERAL HISTOLOGY

Detailed explanation-1: -In endotherms, warm blood from the body’s core typically loses heat to the environment as it passes near the skin. Shrinking the diameter of blood vessels that supply the skin, a process known as vasoconstriction, reduces blood flow and helps retain heat.

Detailed explanation-2: -In warm temperatures, these same blood vessels dilate or widen, increasing the flow of blood to the skin surface, thus allowing heat to leave the body, and keeping the core body temperature from rising to a dangerous level.

Detailed explanation-3: -Cold causes blood vessels to constrict; heat causes them to open up. Under normal circumstances, blood vessels relax in hot weather to increase blood flow to the surface of the skin, helping the body to cool down.

Detailed explanation-4: -Heat therapy increases blood flow to a specific area and improves circulation. This is because heat on an inflamed area causes the blood vessels to dilate, promoting blood flow to the injured area. Applying heat to an affected area can provide comfort and increase muscle flexibility, as well as heal damaged tissue.