Coronary heart disease (CHD) is a form of cardiovascular disease. Explain how a build-up of fatty deposits in the coronary arteries can lead to a heart attack.
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
Coronary heart disease affects millions of people in the UK. It develops over many years and is linked to several lifestyle and genetic risk factors.
Model answer (5 marks)
Fatty deposits (atheroma/plaque) accumulate in the intima of the coronary artery.
The plaque narrows the lumen, reducing the cross‑sectional area for blood flow.
Reduced flow limits the delivery of oxygen and glucose to the myocardium.
The myocardial cells cannot carry out aerobic respiration adequately.
Ischaemia leads to cell death, producing the clinical event known as a heart attack.
The plaque narrows the lumen, reducing the cross‑sectional area for blood flow.
Reduced flow limits the delivery of oxygen and glucose to the myocardium.
The myocardial cells cannot carry out aerobic respiration adequately.
Ischaemia leads to cell death, producing the clinical event known as a heart attack.
Examiner tips
- Use the exact terms atheroma, lumen, ischaemia, myocardial cells; show the causal chain; keep each point short and to the point.
- Remember the command word ‘Explain’ – describe the sequence, not just state facts.
- Include the consequence (cell death) to earn the final mark.
Common mistakes
- Confusing plaque with cholesterol; not specifying the lumen narrowing; omitting the ischaemia step; writing a list of facts instead of a causal explanation.
Mark scheme (5 marks)
- Fatty deposits (atheroma/plaque) build up in the wall of the coronary artery
- The lumen of the coronary artery becomes narrower
- Blood flow to the heart muscle is reduced
- The heart muscle receives less oxygen (and glucose)
- The heart muscle cells cannot respire sufficiently / part of the heart muscle dies, causing a heart attack
Key terms in this question
fatty deposits · heart attack · cardiovascular disease
Related
- All Edexcel A-Level Biology A: Salters-Nuffield (9BN0) revision notes →
- How to answer a "Explain" question →
- Decode the mark scheme abbreviations →
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