describe the role of the skin in temperature regulation, with reference to sweating, vasoconstriction and vasodilation
Skin - protects body from damage, germs, excessive water loss; allows one to feel touch, pain, temperature and pressure; keeps body temperature constant
1. Vasodilation when hot
- Blood vessels near the surface of skin widen
- Allows more blood to flow to the surface
- Heat lost from radiation
- Sweat glands make sweat
- Sweat evaporates and cools body down
- Hairs lay flat; no air trapped, heat can transfer out of body
2. Vasoconstriction when cold
- Blood vessels close up
- Allows less blood to flow to the surface
- Less heat loss from radiation
- Hair erection (goosebumps); muscles contract and makes hair stand up, traps a layer of air to avoid heat from escaping
- Sweat glands stop making sweat
- Shivering; muscles contract quickly and generate extra heat to warm body
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