2.88

Describe the role of the skin in temperature regulation, with reference to sweating, vasoconstriction and vasodilation

• When the body feels that it is too hot:
• Hairs on skin lie flat (less insulating air trapped)
• Sweating starts
• Blood is diverted close to the surface of the skin (more heat radiation)
• When the body feels that it is too cold:
• Hairs on skin stand up (more insulating air trapped)
• Sweating stops
• Shivering starts, so muscles respire more, producing more heat
• Blood is diverted away from the skin (less heat radiated)
• How is blood diverted?
• Arterioles in the skin can open and close in response to nerve messages
• Vasoconstriction: Arteriole closes
• This happens when the body is cold
• Vasodilation: Arteriole opens
• This happens when the body is hot