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How does the hypothalamus control heat loss through blood vessels in the skin?
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Blood sediment in test tubes, showing plasma (clear fluid), red blood cells (red), and the release of hemoglobin into the surrounding plasma (pink).
The hypothalamus acts as the body’s internal thermostat, maintaining homeostasis by monitoring the temperature of the blood flowing through it.12
To promote heat loss, the hypothalamus sends nerve impulses that trigger vasodilation—the widening of blood vessels in the skin. This process increases the volume of warm blood circulating near the skin's surface, allowing heat to be dissipated into the external environment. Conversely, when the body needs to conserve heat, the hypothalamus initiates vasoconstriction, narrowing these vessels to reduce blood flow to the skin and minimize heat loss. This autonomic regulation ensures that the body maintains a stable core temperature despite fluctuations in the environment.1324