# Explain how sound waves are detected by the ear and how nerve impulses are sent to the brain.

> Edexcel A-Level Biology A: Salters-Nuffield (9BN0) — 4.4 Vision and hearing · Explain · 5 marks

> The ear is a sense organ that detects sound. Sound waves enter the ear and are converted into nerve impulses that travel to the brain for processing.

## Mark scheme (5 marks)

1. Sound waves cause the eardrum to vibrate
2. Vibrations are transmitted through the three ossicles (hammer, anvil and stirrup) / middle ear bones
3. The ossicles amplify the vibrations
4. Vibrations pass to the cochlea, which contains hair cells / receptor cells that detect the vibrations
5. Hair cells / receptor cells generate nerve impulses that travel along the auditory nerve to the brain

## Key terms

- [nerve impulses](https://www.gradenine.co.uk/glossary/nerve-impulses)

## Related

- [Revision notes for Edexcel A-Level Biology A: Salters-Nuffield (9BN0)](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-sound-waves-are-detected-57aa506a) · Published by Druglandscape Ltd.