Control of Body Temperature

• What should the human body temperature be kept at in celsius?

  Around 37°C
• Why should the body temperature be kept at 37°C?

  It gives an optimum temperature for enzymes to work
• What is the thermoregulatory centre?

  The part of the brain responsible for maintaining a constant body temperature in warm blooded animals
• What does the thermoregulatory centre in the brain do/contain?

  -monitors and controls body temperature

  -has receptors that monitor the temperature of the blood flowing through the brain

  -receives information (impulses) from temperature receptors in the skin
• What happens in the thermoregulatory centre if the body temperature is too high?

  -blood vessels widen, directing more blood to the surface of the skin

  -more sweat is produced from the sweat glands and evaporates

  -both these mechanisms cause a transfer of energy from the skin to the environment
• What is vasodilation?

  process that occurs when blood vessels in the skin become wider so that more blood flows close to the surface of the skin to increase heat loss
• What happens in the thermoregulatory centre if the body temperature is too low?

  -blood vessels narrow, directing blood away from the surface of the skin

  -sweating stops

  -skeletal muscles uncontrollably contract and relax quickly (shiver), which transfers more heat to the blood
• What is vasoconstriction?

  Process that occurs when blood vessels in the skin become narrower so that less blood flows close to the surface of the skin
• What do temperature receptors in the skin do?

  They give the brain an early warning of changes in the external temperature.
• How do temperature receptors help in regulating body temperature?

  They allow behavior to be adjusted to stop the body temperature from changing.
• What behavior might a person exhibit in response to a drop in external temperature?

  Putting on more clothes.
• What is the only way blood vessels in the skin can adjust energy transfer to the outside?

  Narrowing or widening.
• Why can't blood vessels in the skin move to adjust energy transfer?

  Because they are fixed in place.
• How does the narrowing or widening of blood vessels affect energy transfer?

  It adjusts how much energy is transferred to the outside.
• How does the skin send nervous impulses?

  The skin contains temperature receptors which send nervous impulses to the thermoregulatory centre