# Skin

Source: https://projectgcse.co.uk/biology/human_biology/skin

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- 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