Explain why the coronary arteries are important to the heart, and describe what happens when fatty deposits build up inside them.

Cambridge International IGCSE Biology (0610) — 9.2 Heart · Explain · 4 marks · View as Markdown

Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).

Model answer (4 marks)

Coronary arteries supply the heart muscle with oxygen and glucose.
Without this supply the myocardium cannot respire, contract or function.
When fatty deposits (cholesterol) build up inside the arteries they narrow the lumen.
The reduced blood flow can cause coronary heart disease or a heart attack.

Examiner tips

  • Use the term ‘myocardium’ for heart muscle. Show the causal chain: supply → respiration/contract → function. Mention narrowing of lumen and reduced flow. Link to disease outcome.
  • common_mistakes
  • :
  • Using vague terms like ‘blood supply’ instead of ‘oxygen and glucose’. Failing to state that narrowing reduces flow. Not linking the blockage to heart disease or attack.

Mark scheme (4 marks)

  1. Coronary arteries supply the heart muscle with oxygen (and glucose/food)
  2. Without this supply the heart muscle cannot respire / contract / function
  3. Fatty deposits (cholesterol) build up inside the coronary arteries, narrowing the lumen
  4. This reduces blood flow to the heart muscle, leading to coronary heart disease / a heart attack

Key terms in this question

coronary arteries · fatty deposits

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