BRAINCAKEVasodilation
Vasodilation is the widening of the arterioles that supply the capillaries near the skin surface. It is a response to a rise in core temperature.
When the heat loss centre in the hypothalamus is activated, fewer impulses are sent along sympathetic nerves to the arterioles in the skin. The ring of smooth muscle in their walls relaxes, so the lumen widens. At the same time the shunt vessels constrict, so less blood bypasses the surface.
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Key terms in this lesson
- arteriovenous shunt
- A vessel linking an arteriole directly to a venule, allowing blood to bypass the surface capillaries.
More in Homeostasis
- The Skin
- Keeping Cool
- Keeping Warm
- Control of Core Body Temperature
- Vasoconstriction
- Adaptations for Cold Environments
- Adaptations for Hot Environments
- Cooling The Brain
All 41 lessons in Homeostasis · All Edexcel A-level Biology topics