# Coronary heart disease (CHD) occurs when the coronary arteries become narrowed by a build-up of fatty deposits. Explain how a narrowing of the coronary arteries leads to a heart attack.

> Pearson Edexcel A-Level Biology A (9BI0) — 1.2 Heart, blood and blood vessels · Explain · 5 marks

> Coronary heart disease is one of the leading causes of death in the UK. The coronary arteries supply the heart muscle with blood. When these arteries become partially or fully blocked, the consequences for the heart can be severe.

## Mark scheme (5 marks)

1. The coronary arteries supply the heart muscle with oxygenated blood (and/or glucose/nutrients)
2. Fatty deposits narrow the lumen of the coronary arteries, reducing blood flow
3. Less oxygen (and/or glucose) is delivered to the heart muscle cells
4. The heart muscle cells cannot carry out aerobic respiration at a sufficient rate / energy release is reduced
5. The heart muscle cells die / part of the heart muscle stops contracting, causing a heart attack

## Key terms

- [coronary arteries](https://www.gradenine.co.uk/glossary/coronary-arteries)
- [heart attack](https://www.gradenine.co.uk/glossary/heart-attack)
- [fatty deposits](https://www.gradenine.co.uk/glossary/fatty-deposits)

## Related

- [Revision notes for Pearson Edexcel A-Level Biology A (9BI0)](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/coronary-heart-disease-chd-occurs-when-f818605a) · Published by Druglandscape Ltd.