Control of body temperature

• What is the optimum body temperature for enzyme activity?

  37°C
• What is thermoregulation?

  It maintains stable body temperature for cells
• Where is the thermoregulatory centre located?

  In the hypothalamus of the brain
• How does the thermoregulatory centre detect temperature changes?

  It contains receptors sensitive to blood temperature
• What do skin temperature receptors do?

  Send impulses to the thermoregulatory centre
• What are the key components of the thermoregulatory system?

  • Thermoregulatory centre: Detects blood temperature
  • Skin receptors: Detect external temperature changes
  • Effectors: Carry out responses to maintain temperature
• What happens when body temperature rises above 37°C?

  The brain sends signals to cool the body
• What is the process of sweating?

  Sweat evaporates from the skin, cooling it
• What is vasodilation?

  Blood vessels supplying the skin dilate
• How does vasodilation help in thermoregulation?

  More warm blood flows near the skin surface
• What happens to hairs when the body is too hot?

  Hairs lie flat to reduce insulation
• What is the purpose of sweating?

  To cool the skin through evaporation
• What occurs when body temperature drops below 37°C?

  The brain sends signals to warm the body
• What is shivering?

  Muscles contract rapidly to generate heat
• What is vasoconstriction?

  Blood vessels supplying the skin constrict
• How does vasoconstriction help in thermoregulation?

  Less warm blood reaches the skin surface
• What happens to hairs when the body is too cold?

  Hairs stand up to trap warm air
• Why is thermoregulation important?

  It prevents enzymes from denaturing or slowing
• What are the consequences of being too hot or too cold?

  • Too Hot: Enzymes denature above 40°C
  • Too Cold: Enzyme activity slows, respiration decreases
• What are the responses to body temperature changes?

  Too hot:

  • Sweating: Evaporates sweat, removing heat
  • Vasodilation: More blood at skin, more heat lost
  • Hairs lie flat: Less insulation, more heat lost

  
  

  Too cold:

  • Shivering: Muscle contractions generate heat
  • Vasoconstriction: Less blood near skin, less heat lost
  • Hairs stand up: Traps warm air for insulation
• What is the effect of sweating on body temperature?

  It cools the skin
• What is the effect of shivering on body temperature?

  Generates heat through respiration
• What is the effect of vasoconstriction on body temperature?

  Reduces heat loss
• What is the effect of hairs standing up on body temperature?

  Acts as insulation