Explain how the structure of arteries and veins is related to their functions in the circulatory system.

Pearson Edexcel A-Level Biology A (9BI0) — 1.2 Heart, blood and blood vessels · Explain · 5 marks · View as Markdown

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

Arteries carry blood away from the heart at high pressure. Veins return blood to the heart at low pressure.

Model answer (5 marks)

Arteries have thick, muscular and elastic walls which allow them to withstand and cope with the high pressure of blood pumped from the heart.

Veins have thinner walls and a larger lumen than arteries, and they contain valves.

The valves prevent backflow of blood and ensure that blood flows in one direction towards the heart.

Examiner tips

  • Use the word "thick" for arteries and "thin" for veins. Mention "muscular" and "elastic" for arteries. Explain that valves prevent backflow. Show the link between structure and function.

Common mistakes

  • Confusing the thickness of arterial and venous walls. Forgetting to mention valves in veins. Using vague terms like "strong" instead of "muscular/elastic".

Mark scheme (5 marks)

  1. Arteries have thick muscular/elastic walls
  2. Thick walls withstand / cope with high blood pressure (from the heart)
  3. Veins have thinner walls than arteries / large lumen
  4. Veins have valves
  5. Valves prevent backflow of blood / ensure blood flows in one direction towards the heart

Key terms in this question

vein

Related

More Heart, blood and blood vessels questions

▶ Try answering this question with AI marking (free) →