Describe the differences between arteries and veins in terms of their structure and the conditions under which they carry blood.

Cambridge International IGCSE Biology (0610) — 9.1 Circulatory systems · 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/elastic wall, whereas veins have a thin muscular/elastic wall.
Arteries have a smaller lumen, whereas veins have a wider/larger lumen.
Arteries carry blood at high pressure, whereas veins carry blood at low pressure.
Veins contain valves to prevent back‑flow of blood; arteries do not have valves.

Examiner tips

Use the exact terms ‘thick muscular/elastic wall’, ‘small lumen’, ‘high pressure’, ‘valves’ to match the mark scheme.
Show the contrast clearly – list each feature for arteries then veins to avoid missing a point.
Keep the answer concise – 4 points, 1 sentence each, to fit the 4‑mark question.

Common mistakes

Confusing the wall thickness of arteries and veins, e.g. saying veins are thick. Mistaking the pressure level, e.g. stating veins carry high‑pressure blood. Omitting the valves in veins or claiming arteries have valves.

Mark scheme (4 marks)

Arteries have a thick muscular/elastic wall whereas veins have a thin muscular/elastic wall
Arteries have a smaller lumen whereas veins have a wider/larger lumen
Arteries carry blood at high pressure whereas veins carry blood at low pressure
Veins contain valves to prevent backflow of blood / arteries do not have valves

Key terms in this question

vein