AQA · GCSE · Biology
Course version: 8461 · Version from Sept 2018
If the body temperature is too low, blood vessels constrict…
Full specification wording
Control of body temperature (biology only): If the body temperature is too low, blood vessels constrict (vasoconstriction), sweating stops and skeletal muscles contract (shiver).
When the thermoregulatory centre detects that core body temperature has fallen below the normal set point, it triggers responses that reduce energy transfer to the environment and increase energy…
Checked against the AQA 8461 specification (opens in a new tab) on .
- Point 6 of 7
- 3 key terms
Study notes
From the checked teaching notes for this specification point.
The idea
When the thermoregulatory centre detects that core body temperature has fallen below the normal set point, it triggers responses that reduce energy transfer to the environment and increase energy release in the body. Vasoconstriction occurs when smooth muscle in the walls of skin arterioles contracts, narrowing the vessels and reducing blood flow through skin capillaries; less energy is therefore transferred from the skin to the surroundings. Sweat production stops, so evaporative cooling is reduced. Skeletal muscles contract rapidly and repeatedly in shivering; the increased respiration in muscle cells releases energy as heat, warming the blood and raising core temperature. For example, standing outside in cold weather may cause pale skin, dry skin and shivering as the body attempts to conserve and generate energy. These responses continue until the set point is restored.
What earns the marks
- Vasoconstriction narrows arterioles supplying skin capillaries, reducing blood flow to the skin surface.
- Reduced blood flow decreases energy transfer from the skin to the environment.
- Sweat production stops, so evaporative cooling is reduced.
- Shivering involves rapid contraction of skeletal muscles.
- Increased muscle respiration releases energy that warms the body.
- The responses are coordinated by the thermoregulatory centre as part of negative feedback.
Common mistakes and how to put them right
Confusing vasoconstriction with vasodilation.
Put it right: Vasoconstriction narrows vessels and reduces blood flow when too cold.
Stating that shivering produces energy directly.
Put it right: Muscle contraction increases respiration, which releases energy as heat.
Saying that sweating stops because sweat glands freeze.
Put it right: Sweating stops because the thermoregulatory centre inhibits the sweat glands.
Exam tips
- Use the terms vasoconstriction, sweating stops and shivering precisely, and link each to reduced energy loss or increased energy release.
- Explain shivering in terms of muscle contraction and increased respiration, not just movement.
- When describing vasoconstriction, refer to narrowing of arterioles and reduced blood flow through skin capillaries.
Try the lesson
The start of the Control of body temperature (biology only): If the body temperature is too low, blood vessels constrict (vasoconstriction), sweating stops and skeletal muscles contract (shiver). lesson, made from checked teaching notes for this specification point.
Have a go first
When the body temperature is too low, which response involves the blood vessels?
Listen
When the thermoregulatory centre detects that core body temperature has fallen below the normal set point, it triggers responses that reduce energy transfer to the environment and increase energy release in the body. Vasoconstriction occurs when smooth muscle in the walls of skin arterioles contracts, narrowing the vessels and reducing blood flow through skin capillaries; less energy is therefore transferred from the skin to the surroundings. Sweat production stops, so evaporative cooling is reduced. Skeletal muscles contract rapidly and repeatedly in shivering; the increased respiration in muscle cells releases energy as heat, warming the blood and raising core temperature. For example, standing outside in cold weather may cause pale skin, dry skin and shivering as the body attempts to conserve and generate energy. These responses continue until the set point is restored. A strong answer earns marks for these points. Vasoconstriction narrows arterioles supplying skin capillaries, reducing blood flow to the skin surface. Reduced blood flow decreases energy transfer from the skin to the environment. Sweat production stops, so evaporative cooling is reduced. Shivering involves rapid contraction of skeletal muscles. Exam tip: Use the terms vasoconstriction, sweating stops and shivering precisely, and link each to reduced energy loss or increased energy release.
See it
Key words
Say what each word means before you turn the card.
Vasoconstriction
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Shivering
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Thermoregulatory centre
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See every definition
- Vasoconstriction
- Smooth muscle in the walls of skin arterioles contracts, narrowing the vessels and reducing blood flow through skin capillaries.
- Shivering
- Skeletal muscles contract rapidly and repeatedly, and the increased respiration in muscle cells releases energy as heat.
- Thermoregulatory centre
- The centre that detects when core body temperature has fallen below the normal set point and coordinates the responses as part of negative feedback.
Label the diagram
Some boxes have lost their names. Pick the right name for each number.
1Box 1
2Box 2
3Box 3
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