Control of Body Temperature
Recap Control of Body Temperature for GCSE Biology with this free worksheet and full mark scheme — Foundation and Higher exam-style questions with worked answers for AQA, Edexcel and OCR. A separate (triple) biology topic on how the hypothalamus, sweating, vasodilation and vasoconstriction keep body temperature near 37 °C.
Free downloads
These worksheets and mark schemes are original, written for Virtus Academy and checked against the current AQA, Edexcel and OCR specifications. Every worksheet comes with a full mark scheme.
Topic overview
Body temperature is monitored and controlled by the thermoregulatory centre in the brain, which contains receptors sensitive to the temperature of the blood. This is a Triple-only topic.
The skin also contains temperature receptors, which send impulses to the thermoregulatory centre. Control is essential because enzymes work best at around 37 °C and are denatured if the body gets too hot.
If body temperature is too high, blood vessels dilate — vasodilation — and sweat is produced from the sweat glands, both of which increase heat loss. If it is too low, blood vessels constrict, sweating stops, and skeletal muscles contract rapidly in shivering, which requires respiration and releases some energy as heat.
Revision notes
Monitoring temperature
The thermoregulatory centre in the brain contains receptors sensitive to the temperature of the blood flowing through it.
The skin also contains temperature receptors that send impulses to this centre. Together they give information about both core and surface temperature.
Cooling down
Vasodilation: blood vessels supplying the skin capillaries dilate, so more blood flows near the surface and more heat is lost by radiation.
Sweat is produced from sweat glands. As it evaporates it transfers energy from the skin to the environment, cooling the body.
Warming up
Vasoconstriction: blood vessels supplying the skin capillaries constrict, so less blood flows near the surface and less heat is lost.
Sweating stops. Skeletal muscles contract rapidly in shivering, which requires respiration, and some of the energy released warms the body.
Key points
- The thermoregulatory centre monitors blood temperature.
- Skin temperature receptors also send impulses to it.
- Vasodilation increases heat loss.
- Sweating cools the body as sweat evaporates.
- Vasoconstriction reduces heat loss.
- Shivering releases energy as heat through respiration.
Worked examples
Example 1
Explain how sweating helps to cool the body. [2 marks]
Model answer
Sweat is produced from the sweat glands onto the surface of the skin (1 mark). As the sweat evaporates it transfers energy from the skin to the environment, cooling the body (1 mark).
Example 2
Explain how shivering helps to raise body temperature. [2 marks]
Model answer
Skeletal muscles contract and relax rapidly (1 mark), which requires respiration, and some of the energy released by respiration warms the body (1 mark).
Example 3
Explain what happens to the blood vessels supplying the skin when the body is too hot. [2 marks]
Model answer
The blood vessels dilate, which is called vasodilation (1 mark), so more blood flows through the capillaries near the skin surface and more heat is lost to the surroundings (1 mark).
Common mistakes
Saying capillaries move closer to the surface.
They do not move. The vessels supplying them dilate or constrict, changing blood flow.
Saying sweat cools the body just by being wet.
It is the evaporation that transfers energy away from the skin.
Confusing vasodilation and vasoconstriction.
Dilation is for cooling down; constriction is for retaining heat.
Forgetting to link shivering to respiration.
The heat comes from the energy released by respiration in the muscles.
Exam tips
- Use the terms vasodilation and vasoconstriction precisely.
- Say evaporation when explaining how sweat cools.
- Link shivering to muscle contraction and respiration.
- Remember this is a Triple-only topic.
Key terms
- Thermoregulatory centre
- The brain region monitoring and controlling body temperature.
- Vasodilation
- Widening of blood vessels to increase heat loss.
- Vasoconstriction
- Narrowing of blood vessels to reduce heat loss.
- Evaporation
- The process by which sweat removes energy from the skin.
Related topics
Written and reviewed against the current AQA, Edexcel and OCR specifications. Spotted an error? Let us know.