thermoregulation

• 37 degrees Celsius is optimum temperature for enzyme action (body temperature)
• if you increase your body temperature enzymes denature because the active site changes shape so the substrate cant bind to the active site therefore reactions cant take place
• if you decrease body temperature there is not enough energy for enzymes to catalyse reactions
• hypothalamus is the thermoregulatory centre. it monitors blood temperature and sends signals to effectors, this is how our bodies know when core temperature has changed.
• when temperature needs top be decreased- heat loss needs to be increased by:

  sweating- water evaporates off your skin taking heat with it

  vasodilation- blood vessels dilate so more blood flows to the surface of the skin so heat is lost by radiation
• when temperature needs to be increased- the rate of heat loss needs to be decreased by:

  • shivering- muscles contract releasing energy from respiration (exothermic)
  • vasoconstriction- blood vessels constrict reducing blood flow so there is less heat loss by radiation
  • goosebumps- hairs trap a layer of air close to skin to reduce heat loss