# Explain the role of valves in the heart and why they are important for the efficient circulation of blood.

> WJEC GCSE Biology (Wales) — 1.4.2 The heart · Explain · 4 marks

## Mark scheme (4 marks)

1. Valves prevent the backflow of blood
2. Valves open when pressure behind them is greater, and close when pressure in front is greater
3. Atrioventricular (bicuspid/tricuspid) valves are located between the atria and ventricles
4. Semilunar valves are located at the exits of the ventricles (in the aorta and pulmonary artery) to prevent blood returning to the ventricles

## Key terms

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

## Related

- [Revision notes for WJEC GCSE Biology (Wales)](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-the-role-of-valves-in-cd1bb4ab) · Published by Druglandscape Ltd.