4.5.2.4 Control of Body Temperature (biology only)

Question 1

What is normal human body temperature?

Answer 1

37 degrees C

Question 2

How is your body temperature monitored and controlled?

Answer 2

• monitored and controlled by the thermoregulatory centre in the brain
• the thermoregulatory centre contains receptors sensitive to the temperature of the blood
• the skin also contains temperature receptors and these sends electrical (nervous) impulses down sensory neurones to the thermoregulatory centre

Question 3

What happens when your body temperature gets too high?

Answer 3

• body temp gets too high e.g. person is exercising
• sweat glands release sweat onto the surface of the skin, the sweat now evaporates and this causes energy transfer away from the body cooling the body down
• the body can also cool itself down by flushing
  
  • under the surface of the skin - there is a fine network of blood capillaries
  • these capillaries are supplied with blood by blood vessels deeper in the skin
  • if body temperature is too high, the blood vessels supplying the capillaries dilate - vasodilation (aka get wider)
  • as the blood vessels have dilated more blood flows through capillaries
  • and more blood flows closer to the surface of the skin
  • more heat (energy) can now transfer out of the blood so body temperature returns to normal

Question 4

What happens when your body temperature gets too low?

Answer 4

• blood vessels supplying the capillaries constrict (become narrower) - vasoconstriction
  
  • blood vessels are narrower so less blood flows through capillaries
  • and blood flows less close to the surface of the skin
  • resulting in less heat energy lost from the body
• less blood flows through the capillaries and less heat is lost from the body
• shiver - our skeletal muscles contract - uses energy - aerobic respiration uses oxygen and glucose - generates heat
  
  • releases heats from respiration which warms the body
• stop sweating as when you sweat the sweat glands release sweat onto the surface of the skin, the sweat now evaporates and this takes energy from the body cooling the body down
• hair stands on end creating an insulating layer, trapping warm air