AQA GCSE Biology

Revision Notes

5.2.6 Control of Body Temperature

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

A cross-section of human skin, IGCSE & GCSE Biology revision notes

Human skin contains structures involved in processes that can increase or reduce heat loss to the surroundings

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

 

Responses in the skin when hot, IGCSE & GCSE Biology revision notes

Responses in the skin when the body temperature is too high and needs to decrease

  • 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)

 

Responses in skin when cold, IGCSE & GCSE Biology revision notes

Responses in the skin when body temperature is too low and needs to increase

Higher Tier Only

Examples of Body Temperature Control

  • 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 control table

Body temperature control table, downloadable IGCSE & GCSE Biology revision notes

Regulating body temperature, IGCSE & GCSE Biology revision notes

Remember homeostasis involves the maintenance of constant internal environment; temperature control is an example of negative feedback

Author: Jenna

Jenna studied at Cardiff University before training to become a science teacher at the University of Bath specialising in Biology (although she loves teaching all three sciences at GCSE level!). Teaching is her passion, and with 10 years experience teaching across a wide range of specifications – from GCSE and A Level Biology in the UK to IGCSE and IB Biology internationally – she knows what is required to pass those Biology exams.
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