Thermoregulation

• what is dermis

  lower tissue of the skin
• what is epidermis

  upper tissue of the skin
• define thermoregulation

  maintaining a constant internal body temperature
• that is the optimum temperature of enzymes in the human body

  37°C
• what happens if the temperature exceeds 37°C to the enzymes

  Active site changes -> denatures
• what happens if the temperature falls below 37°C to the enzymes

  • enzyme activity slows down
• what's the name of the brain's thermoregulatory centre

  hypothalamus
• how does the hypothalamus detect changes in temperature

  • contains receptor which are sensitive to blood temperature in brain
  • and also receives impulses from epidermis (outer layer) + dermis (inner layer) of the skin about external temp
• List 3 ways the body responds to increased temperatures

  • vasodilation
  • sweat
  • erector muscles
• how does erector muscles cool you down

  • base of hairs relax
  • causes hairs to lie flat against skin
• how does sweat cool you down

  • produced by sweat glands
  • released onto surface of skin through pores -> cooling effect
  • due to sweat evaporating + transferring energy from skin to environment
• how does sweat provide a cooling effect

  • due to sweat evaporating + transferring energy from skin to environment
• describe vasodilation

  • blood vessels close to surface of skin DILATE (wider)
  • allows more blood flow
  • so more thermal energy can be transferred to surroundings
  • AWAY from body
• when is the temperature deemed too hot

  above 37°C
• list 4 ways the body responds to decreased temperatures

  • shivering
  • vasoconstriction
  • little sweat produced
  • erector muscles contract
• describe process of vasoconstriction

  • blood vessels near surface of skin CONSTRICT (narrower)
  • to lessen blood flow
  • reduces amount of energy transferred to surroundings
• explain how shivering increases body temperature

  • happens when muscles contract + relax quickly + automatically
  • increases rate of respiration
  • transfers MORE energy to warm body
• explain how raised hairs raise body temp

  • base of hairs contract
  • causes hairs to stand on end
  • trap insulating layer of air