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Why do blood vessels in the skin widen when the body needs to lose heat?

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Learn how regenerative properties of the skin helps to protect the human body from the external environment — human skin Human skin, whose cells are generated continuously by the body, serves as a protective barrier between the inside of the human body and the environment.

Blood vessels in the skin widen—a process known as vasodilation—to facilitate the dissipation of excess body heat.1

The body acts as a thermoregulatory system, with the hypothalamus in the brain functioning like a thermostat to maintain a constant internal temperature. When the body needs to lose heat, the nervous system triggers the widening of cutaneous blood vessels. This increases the volume of warm blood flowing to the surface of the skin, allowing heat to be released into the external environment.213

This mechanism is essential because the skin serves as a cooling device for the body, receiving a blood supply far in excess of its own biological needs to ensure efficient heat distribution and disposal. When combined with other cooling processes, such as the evaporation of sweat from the skin's surface, vasodilation helps the body maintain a stable core temperature.23