Describe the structural differences between an artery and a vein that allow each vessel to carry out its function.

Cambridge International IGCSE Biology (0610) — 9.3 Blood vessels · Describe · 4 marks · View as Markdown

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

Model answer (4 marks)

Arteries have a thick muscular and elastic wall, giving them a narrow lumen and the strength to withstand high pressure.
Veins have a thinner wall, a wider lumen and valves that prevent back‑flow, allowing blood to return to the heart at low pressure.

Examiner tips

Use the words "thick muscular/elastic wall" and "narrow lumen" for arteries, and "thin wall, wide lumen, valves" for veins. Mention the pressure difference to justify the structural differences. Keep the answer concise – 4 marks can be earned with two points per vessel.

Common mistakes

Confusing the thickness of the wall with the lumen size. Forgetting to mention valves in veins. Using vague terms such as "strong" or "weak" instead of "thick" or "thin".

Mark scheme (4 marks)

Arteries have a thick muscle layer / thick elastic layer (compared to veins), allowing them to withstand or maintain high blood pressure.
Arteries have a narrow lumen (compared to veins), to maintain high pressure.
Veins have a larger / wider lumen (compared to arteries), as blood travels at low pressure.
Veins contain valves to prevent the backflow of blood.

Key terms in this question

artery · vein