# Describe how a nerve impulse travels from a receptor to an effector in the nervous system.

> WJEC A-Level Biology (Wales) — 3.8 The nervous system · Describe · 5 marks

## Mark scheme (5 marks)

1. Receptor detects a stimulus
2. Nerve impulse travels along a sensory neurone to the CNS (brain or spinal cord)
3. Impulse passes through a relay neurone in the CNS
4. Impulse travels along a motor neurone from the CNS to the effector
5. Effector (muscle or gland) responds to the impulse

## Key terms

- [receptor](https://www.gradenine.co.uk/glossary/receptor)
- [effector](https://www.gradenine.co.uk/glossary/effector)
- [nerve impulse](https://www.gradenine.co.uk/glossary/nerve-impulse)

## Related

- [Revision notes for WJEC A-Level Biology (Wales)](https://www.gradenine.co.uk/learn)
- [How to answer "Describe" 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/describe-how-a-nerve-impulse-travels-242454ef) · Published by Druglandscape Ltd.