# A patient is admitted to hospital with a core body temperature of 40.8 °C following prolonged exercise in hot conditions. Explain how the hypothalamus coordinates the physiological responses that act to reduce core body temperature back to the normal set point.

> OCR A-Level Biology A (H420) — 5.1 Communication and homeostasis · Explain · 4 marks

## Mark scheme (4 marks)

1. The hypothalamus thermoreceptors detect the rise in blood temperature above the set point
2. The hypothalamus sends nerve impulses via the efferent nervous system to effectors in the skin
3. Vasodilation of arterioles in the skin increases blood flow to the surface, increasing heat loss by radiation
4. Increased sweating causes evaporation of water from the skin surface, removing latent heat from the body

## Key terms

- [hypothalamus](https://www.gradenine.co.uk/glossary/hypothalamus)
- [set point](https://www.gradenine.co.uk/glossary/set-point)

## Related

- [Revision notes for OCR A-Level Biology A (H420)](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

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Source: [GradeNine](https://www.gradenine.co.uk/q/a-patient-is-admitted-to-hospital-973bedba) · Published by Druglandscape Ltd.