Blood supply

This is far more than would be expected for metabolic needs, these are necessary to provide thermoregulation. Vessels close down (vasoconstrict) when cold so less heat is lost, under sympathetic control. Removes excess heat by vasodilation.

Each part of the skin is involved in preserving the integrity of the body.

• Protection against dehydration.
• Melanin protects from UV and IR.
• Against tearing from collagen of dermis, against abrasion stratified epidermal layers, papillae.
• Temperature regulation by blood vessels.
• Sensitivity of skin has a sexual function - erogenous zones.
• Minor metabolic role can produce vitamin D.