Skin

• The skin is a barrier to the outside world against bacteria etc.
• The skin is also very sensitive to we can feel things.
• The skin's main function is temperature control.
• Below is how the skin is able to change the bodies temperature.

Cooling the body:

• Blood capillaries widen (vasodilatation) to bring more blood near the surface of the skin so heat can be lost into the surroundings by radiation and convection
• Sweat is produced which, as it evaporates, has a cooling effect on the body
• Hairs lie flat which allows warm air to escape faster

Warming the body:

• Blood capillaries in the skin become more narrow (vasoconstriction) so less heat is lost into the surroundings
• Sweating decreases so less heat is lost
• Hairs on body stand up on end to trap air which reduces warm air escaping so rapidly