# Explain how the hormone adrenaline prepares the body for a 'fight or flight' response during a stressful situation.

> Pearson Edexcel A-Level Biology A (9BI0) — 4.5 Hormonal coordination · Explain · 5 marks

> When a person encounters a frightening situation, such as being chased by a dog, the body responds rapidly by releasing a hormone that causes a number of physiological changes.

## Mark scheme (5 marks)

1. Adrenaline is released from the adrenal glands
2. Adrenaline travels in the blood to target organs
3. Heart rate increases, delivering more oxygen and glucose to muscles
4. Glycogen is converted to glucose, increasing blood glucose concentration
5. These changes provide more energy for muscles so the person can fight or run away

## Key terms

- [adrenaline](https://www.gradenine.co.uk/glossary/adrenaline)
- [fight or flight](https://www.gradenine.co.uk/glossary/fight-or-flight)

## Related

- [Revision notes for Pearson Edexcel A-Level Biology A (9BI0)](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/explain-how-the-hormone-adrenaline-prepares-e7b4cc83) · Published by Druglandscape Ltd.