Identify and describe What Is Thermoregulation?, The Role of the Hypothalamus and Warming Up: Conserving Heat in the context of control of body temperature (biology only).
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GCSE Biology Revision
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GCSE Biology revision
Control of body temperature (biology only)
The human nervous system
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Explain the relationships between What Is Thermoregulation?, The Role of the Hypothalamus and Warming Up: Conserving Heat and how they contribute to control of body temperature (biology only).
Apply and analyse knowledge of What Is Thermoregulation?, The Role of the Hypothalamus and Warming Up: Conserving Heat to interpret unfamiliar information about control of body temperature (biology only).
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Key knowledge
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What Is Thermoregulation?
- Thermoregulation is the process by which the body maintains a stable internal temperature as part of homeostasis
- Body temperature must be kept at around 37°C to allow cells and enzymes to function properly
- If temperature drops too low, enzyme activity slows down; if it rises too high, enzymes denature and stop working
The Role of the Hypothalamus
- The thermoregulatory centre, located in the hypothalamus in the brain, acts as the body's thermostat
- Temperature receptors found throughout the body — mainly in the skin and blood vessels — detect changes in body temperature
- These receptors constantly send information to the thermoregulatory centre, which decides whether the body needs to warm up or cool down
Warming Up: Conserving Heat
- Vasoconstriction is the narrowing of blood vessels near the skin surface, reducing blood flow and limiting heat loss to the surroundings
- Erector muscles contract to make hairs stand on end, trapping a layer of insulating air close to the skin to reduce heat loss
Warming Up: Generating Heat
- Shivering involves the automatic contraction of muscles, which requires energy from respiration
- The chemical reactions involved in respiration release heat energy as a waste product, which warms the body up
Cooling Down: Vasodilation and Hair Position
- Vasodilation is the widening of blood vessels near the skin surface, allowing more warm blood to flow close to the skin and transfer heat to the surroundings
- Erector muscles relax, allowing hairs to lie flat so that less insulating air is trapped and more heat can be lost
Cooling Down: Sweating
- Sweat glands release sweat — a mixture of water and salts — onto the surface of the skin
- As sweat evaporates, it takes heat energy away from the body, because a large amount of energy is required to evaporate water, leaving the body cooler