# A person is rushed to hospital after collapsing. Doctors find that a blockage in a coronary artery has reduced blood flow to the heart muscle. Explain why a blockage in a coronary artery is life-threatening, referring to the role of the heart and blood vessels in the cardiovascular system.

> OCR A-Level Biology B — Advancing Biology (H422) — 2.5 Cardiovascular system · Explain · 5 marks

> Coronary arteries supply the heart muscle itself with oxygenated blood. If a coronary artery becomes blocked, the heart muscle in that region no longer receives an adequate blood supply.

## Mark scheme (5 marks)

1. The heart is the organ that pumps blood around the body, so the heart muscle must continuously contract
2. Arteries carry blood away from the heart under high pressure, and coronary arteries supply the heart muscle with oxygenated blood / oxygen and nutrients
3. If the coronary artery is blocked, the heart muscle cells are deprived of oxygen / nutrients
4. Without oxygen the heart muscle cells cannot respire / produce energy, so the heart cannot contract properly / stops beating
5. If the heart stops pumping, blood is no longer circulated to the rest of the body / organs are deprived of oxygen, which is life-threatening

## Key terms

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

## Related

- [Revision notes for OCR A-Level Biology B — Advancing Biology (H422)](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/a-person-is-rushed-to-hospital-ecebf116) · Published by Druglandscape Ltd.