B12 Homeostasis in action

• Body temperature is monitored and controlled by the thermoregulatory centre in the brain
• • the thermoregulatory centre contains receptors sensitive to the temperature of the blood
  • the skin contains temperature receptors and sends nervous impulses to the thermoregulatory centre
• If the body temperature is too high:

  • blood vessels dilate (vasodilation)
  • sweat is produced from the sweat glands
  • both of these mechanisms cause energy transfer from the skin to the environment
• If the body temperature is too low:

  • blood vessels constrict (vasoconstriction)
  • sweating stops
  • skeletal muscles contract (shivering) - muscle cells increase rate of respiration releasing heat