# Describe the changes that occur in the thorax during inspiration to move air into the lungs.

> Cambridge International IGCSE Biology (0610) — 11.1 Gas exchange in humans · Describe · 4 marks

## Mark scheme (4 marks)

1. The external intercostal muscles contract, raising the ribcage up and out
2. The diaphragm contracts and flattens
3. The volume of the thorax increases
4. Thoracic pressure falls below atmospheric pressure, so air moves into the lungs

## Key terms

- [inspiration](https://www.gradenine.co.uk/glossary/inspiration)
- [thorax](https://www.gradenine.co.uk/glossary/thorax)

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- [Revision notes for Cambridge International IGCSE Biology (0610)](https://www.gradenine.co.uk/learn)
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Source: [GradeNine](https://www.gradenine.co.uk/q/describe-the-changes-that-occur-in-33cf6871) · Published by Druglandscape Ltd.