controlling body temperature

• • body temperature is controlled and monitored by thermoregulatory centre in brain
  • it contains receptors sensitive to temperature of blood
  • skin contains temperature receptors and sends nervous impulses to thermoregulatory centre
• • when the body temperature is too high, sweat produces from sweat glands and evaporates from skin
  • blood vessels supplying skin dilate, so more blood flows close to surface of skin (vasodilation)
  • these methods help transfer energy from skin to environment
• when body temperature is too low:

  • no sweat produced
  • hairs stand up to trap insulating layer of air
  • blood vessels constrict to close skin's blood supply (vasoconstriction)
  • muscles contract - shivering
  • needs respiration, so energy transferred to warm body