# A cyclist is riding along a road when they see a red traffic light ahead. They decide to apply the brakes. Explain how the nervous system coordinates this response, from detecting the red light to the muscles in the hand acting on the brake lever.

> Eduqas A-Level Biology — 3.8 The nervous system · Explain · 5 marks

## Mark scheme (5 marks)

1. The eye acts as the receptor, detecting the red light (stimulus)
2. A nerve impulse is sent along a sensory neurone to the brain / central nervous system
3. The brain (CNS) processes the information and coordinates a response
4. A nerve impulse is sent along a motor neurone from the brain to the effector
5. The muscles in the hand act as the effector and contract to apply the brakes

## Related

- [Revision notes for Eduqas A-Level Biology](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)

---
Source: [GradeNine](https://www.gradenine.co.uk/q/a-cyclist-is-riding-along-a-24b6848e) · Published by Druglandscape Ltd.