cooling mechanisms

• vasodilation of blood vessels that supply skin capillaries

  • capillaries in the skin have increased volume of blood- so loses heat to the environment via radiation
  • arterioles have muslces in their walls which can relax or contract- these muscles relax to allow vasodialation
• sweating

  • sweating cools the skin via evaporation- heat energy from the body converts liquid water into water vapour
  • less effective in humid conditions- reduced concentration gradient so sweat evaporates slower
• flattening of hairs

  • hair erector pilli muscles relax, hairs lie flat
  • stops formation of insulating layer via trapped air and allows air to circulate over skin- heat can then leave via radiation