AQA · GCSE · Biology
Course version: 8461 · Version from Sept 2018
(HT only) Students should be able to explain how these mechanisms lower or…
Full specification wording
Control of body temperature (biology only): (HT only) Students should be able to explain how these mechanisms lower or raise body temperature in a given context.
The hypothalamus monitors blood temperature and triggers responses that either lower or raise body temperature.
Checked against the AQA 8461 specification (opens in a new tab) on .
- Point 7 of 7
- 4 key terms
Study notes
From the checked teaching notes for this specification point.
The idea
The hypothalamus monitors blood temperature and triggers responses that either lower or raise body temperature. When too hot, sweating increases and evaporation of sweat removes latent heat from the skin; vasodilation widens skin arterioles so more blood flows near the surface and radiates heat. When too cold, shivering contracts muscles rapidly, releasing heat from respiration; vasoconstriction narrows skin arterioles, reducing heat loss; sweating stops and hairs stand erect to trap insulating air. In a context such as a marathon runner on a hot day, explain each mechanism by linking the stimulus, the response and the resulting heat transfer, rather than listing responses alone.
What earns the marks
- Identify the stimulus as a rise or fall in core body temperature detected by the hypothalamus.
- For cooling, link sweating to evaporation of water from the skin surface, which transfers latent heat away from the body.
- For cooling, link vasodilation to increased blood flow through surface capillaries, increasing heat loss by radiation.
- For warming, link shivering to rapid muscle contraction and increased respiration, which releases heat energy.
- For warming, link vasoconstriction to reduced blood flow near the skin surface, decreasing heat loss by radiation.
- Explain that these responses are coordinated by the nervous system as negative feedback, restoring core temperature towards a set point.
Common mistakes and how to put them right
Saying sweating cools the body because sweat is cold.
Put it right: Evaporation of sweat removes latent heat from the skin.
Confusing vasodilation with vasoconstriction.
Put it right: Vasodilation widens arterioles to lose heat, while vasoconstriction narrows them to conserve heat.
Stating that shivering creates heat without linking it to respiration.
Put it right: Rapid muscle contraction increases respiration, which releases heat energy.
Exam tips
- Use the context given in the question, such as exercise in hot weather or standing in cold water, and apply each mechanism to that situation.
- Write cause-and-effect chains: stimulus, detection by hypothalamus, response, effect on heat gain or loss.
- Use precise terms such as vasodilation, vasoconstriction, evaporation and latent heat rather than vague words like 'blood moves'.
Try the lesson
The start of the Control of body temperature (biology only): (HT only) Students should be able to explain how these mechanisms lower or raise body temperature in a given context. lesson, made from checked teaching notes for this specification point.
Have a go first
A person walks into a cold room. Which response helps to lower heat loss from the skin?
Listen
The hypothalamus monitors blood temperature and triggers responses that either lower or raise body temperature. When too hot, sweating increases and evaporation of sweat removes latent heat from the skin; vasodilation widens skin arterioles so more blood flows near the surface and radiates heat. When too cold, shivering contracts muscles rapidly, releasing heat from respiration; vasoconstriction narrows skin arterioles, reducing heat loss; sweating stops and hairs stand erect to trap insulating air. In a context such as a marathon runner on a hot day, explain each mechanism by linking the stimulus, the response and the resulting heat transfer, rather than listing responses alone. A strong answer earns marks for these points. Identify the stimulus as a rise or fall in core body temperature detected by the hypothalamus. For cooling, link sweating to evaporation of water from the skin surface, which transfers latent heat away from the body. For cooling, link vasodilation to increased blood flow through surface capillaries, increasing heat loss by radiation. For warming, link shivering to rapid muscle contraction and increased respiration, which releases heat energy. A common slip: Saying sweating cools the body because sweat is cold. Instead, evaporation of sweat removes latent heat from the skin. Exam tip: Use the context given in the question, such as exercise in hot weather or standing in cold water, and apply each mechanism to that situation.
Key words
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Thermoregulation by the nervous system
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Heat transfer by radiation and evaporation
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Coordination between detection and response
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Homeostasis and negative feedback
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See every definition
- Thermoregulation by the nervous system
- The hypothalamus monitors blood temperature and triggers responses that either lower or raise body temperature, coordinated by the nervous system as negative feedback.
- Heat transfer by radiation and evaporation
- Vasodilation widens skin arterioles so more blood flows near the surface and radiates heat, while evaporation of sweat removes latent heat from the skin.
- Coordination between detection and response
- Each mechanism is explained by linking the stimulus, the response and the resulting heat transfer, with responses coordinated as negative feedback restoring core temperature towards a set point.
- Homeostasis and negative feedback
- Responses such as sweating, vasodilation, shivering and vasoconstriction are coordinated by the nervous system as negative feedback, restoring core temperature towards a set point.
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