How Does the Body Control Its Temperature?
Learn how the brain controls body temperature using sweating, shivering and changes in blood flow, with clear GCSE Biology explanations and an exam tip.
The body controls its temperature by detecting changes and adjusting how much energy it loses or produces. A thermoregulatory centre in the brain monitors body temperature and coordinates the response.
How is a change detected?
The thermoregulatory centre contains receptors that detect the temperature of the blood. Temperature receptors in the skin also send nerve impulses to it. A receptor is a cell that detects a change; a nerve impulse is an electrical signal that carries information.
What happens when the body is too hot?
Blood vessels near the skin widen. This is called vasodilation: more blood flows close to the skin, so more energy is transferred to the surroundings. Sweat glands also produce sweat. As the sweat evaporates, it transfers energy away from the skin, cooling the body.
What happens when the body is too cold?
Blood vessels near the skin narrow. This is called vasoconstriction: less blood flows close to the skin, reducing energy loss. Sweating stops, and skeletal muscles contract rapidly to make the body shiver. Shivering increases energy transfer from respiration, helping to warm the body.
For example, if you become hot while exercising, the thermoregulatory centre detects the change and triggers sweating and vasodilation. As your body cools, those responses are reduced. This is homeostasis: regulating internal conditions so cells can function well.
Common exam mistake: Do not reverse vasodilation and vasoconstriction. Blood vessels near the skin widen when you are too hot and narrow when you are too cold. This explanation assumes AQA GCSE separate Biology and uses content shared by Foundation and Higher tier; explaining the mechanisms in a given context is Higher-tier content.
