# Adrenaline is a hormone released during the 'fight-or-flight' response. Explain how adrenaline prepares the body to respond to a threat, including reference to where it is produced and how it reaches its target organs.

> WJEC A-Level Biology (Wales) — 4.3 Variation and evolution · Explain · 5 marks

## Mark scheme (5 marks)

1. Adrenaline is produced / released by the adrenal gland
2. Adrenaline travels in the blood(stream) to target organs
3. Adrenaline increases heart rate (and/or breathing rate), increasing oxygen / blood flow to muscles
4. Glycogen is converted into glucose (in cells / the liver)
5. This raises blood glucose levels so that glucose is available for respiration (to release energy)

## Key terms

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

## Related

- [Revision notes for WJEC A-Level Biology (Wales)](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/adrenaline-is-a-hormone-released-during-c5a35445) · Published by Druglandscape Ltd.