Control of Body Temperature (AQA GCSE Biology): Revision Note

Monitoring of body temperature

• The human body needs to maintain a temperature at which enzymes work best, around 37°C

• Processes such as respiration release energy as heat; and the body loses heat energy to its surroundings – the energy gained and lost must be regulated to maintain a constant core body temperature

• Body temperature is monitored and controlled by the thermoregulatory centre in the brain

• The thermoregulatory centre contains receptors sensitive to the temperature of the blood

• The skin contains temperature receptors and sends nervous impulses to the thermoregulatory centre

Diagram of cross section of human skin

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Controlling body temperature

• If the body temperature is too high, blood vessels dilate (vasodilation) and sweat is produced from the sweat glands

• Both these mechanisms cause a transfer of energy from the skin to the environment, cooling the body down

Diagram of skin responses to high body temperature

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• If the body temperature is too low, blood vessels constrict (vasoconstriction), sweating stops and skeletal muscles contract (shiver)

• These mechanisms reduce heat loss to the surroundings (with skeletal muscle contraction increasing heat released in the body)

 Diagram of skin responses to low body temperature

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Examples of body temperature control

Higher Tier Only

• The mechanisms described above lower or raise body temperature

• In the exam, you may be given examples of different contexts in which the body temperature needs to decrease (when someone is too hot) or increase (when someone is too cold)

• Learn the following concepts to ensure you can suggest what changes are happening and why:

Body temperature regulation summary table

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