IMMUNOLOGY

Detailed explanation-1: -Blood vessels in the dermis dilate to promote heat loss (vasodilation) or constrict to reduce heat loss (vasoconstriction).

Detailed explanation-2: -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 ([link]b).

Detailed explanation-3: -Normally, the vessels that supply blood to the skin constrict or narrow in response to cold temperatures. This reaction, called “vasoconstriction, ‘’ decreases blood flow to the skin, which helps to minimize heat loss from the warm blood and therefore preserve a normal internal or “core” temperature.

Detailed explanation-4: -Human skin blood flow serves crucial roles in both thermoregulatory and haemodynamic homeostasis. During exposure to cold environments, vasoconstriction in the skin is the primary autonomic response and first line of defense against excessive reduction in body temperature.

Detailed explanation-5: -Since the blood vessels are narrower than they were before, less blood flows through the skin and thus less heat can escape into the environment via radiation, convection, and conduction.