# The heart has four chambers and valves that work together to pump blood around the body. Explain how the structure of the heart allows it to pump deoxygenated blood to the lungs and oxygenated blood to the rest of the body at the same time.

> Edexcel A-Level Biology A: Salters-Nuffield (9BN0) — 1.2 Heart, blood and blood vessels · Explain · 5 marks

> The human heart is a muscular organ that acts as a double pump. The right side receives deoxygenated blood returning from the body and pumps it to the lungs. The left side receives oxygenated blood from the lungs and pumps it to the rest of the body.

## Mark scheme (5 marks)

1. The heart has two separate sides (left and right), preventing mixing of oxygenated and deoxygenated blood
2. The right ventricle pumps deoxygenated blood to the lungs via the pulmonary artery
3. The left ventricle pumps oxygenated blood to the rest of the body via the aorta
4. The left ventricle has a thicker muscular wall than the right ventricle, generating greater pressure to pump blood around the whole body
5. Valves prevent the backflow of blood, ensuring blood flows in one direction through the heart

## Key terms

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

## 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/the-heart-has-four-chambers-and-0b0c6d2c) · Published by Druglandscape Ltd.