Explain why the left ventricle has a thicker muscular wall than the right ventricle.

WJEC GCSE Biology (Wales) — 1.4.2 The 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)

1. The left ventricle pumps blood to the body (systemic circulation).
2. The right ventricle pumps blood only to the lungs (pulmonary circulation).
3. The left ventricle must generate a higher pressure to overcome the resistance of the systemic circulation.
4. A thicker muscular wall allows the left ventricle to contract more forcefully and produce the required pressure.

Examiner tips

Use the exact terms ‘systemic circulation’ and ‘pulmonary circulation’.
Show the logical link: higher pressure needed → thicker wall needed.
Keep each point concise and separate with numbers or bullets.

Common mistakes

Confusing the circulations or using ‘body’ instead of ‘systemic’.
Failing to mention the pressure difference or the reason for the thicker wall.

Mark scheme (4 marks)

The left ventricle pumps blood to the body / around the whole body (systemic circulation)
The right ventricle only pumps blood to the lungs (pulmonary circulation)
The left ventricle must generate greater / higher pressure (than the right ventricle)
A thicker muscular wall allows the left ventricle to contract more forcefully / with more power

Key terms in this question

ventricle · muscular wall