# Arteries have a thick layer of smooth muscle and elastic fibres in their walls, whereas veins have only a small amount of each. Explain how the wall structure of arteries is suited to the high-pressure blood flow they carry.

> Cambridge International IGCSE Biology (0610) — 9.3 Blood vessels · Explain · 4 marks

## Mark scheme (4 marks)

1. Thick elastic fibres allow the artery wall to stretch under high pressure without bursting
2. Elastic fibres recoil / spring back to maintain a continuous blood pressure between heartbeats
3. Thick smooth muscle layer controls the diameter (lumen) of the artery by contracting or relaxing
4. The small lumen helps to maintain high blood pressure

## Key terms

- [smooth muscle](https://www.gradenine.co.uk/glossary/smooth-muscle)
- [elastic fibres](https://www.gradenine.co.uk/glossary/elastic-fibres)

## Related

- [Revision notes for Cambridge International IGCSE Biology (0610)](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/arteries-have-a-thick-layer-of-581f92e1) · Published by Druglandscape Ltd.