Heart chambers vary in wall thickness based on pumping function

Steps:

• Recall that the heart has four chambers: two atria (upper) and two ventricles (lower).
• Atria receive blood and have thinner walls for low-pressure flow.
• Ventricles pump blood; left ventricle sends oxygenated blood to the body via aorta under high pressure.
• Right ventricle pumps to lungs under lower pressure, so its walls are thinner than the left.

Why B is correct:

• The left ventricle must generate high pressure to pump blood throughout the body, requiring the thickest muscular walls per cardiac anatomy.

Why the others are wrong:

• A. Left atrium receives blood from lungs at low pressure, so walls are thin.
• C. Right atrium receives deoxygenated blood at low pressure, so walls are thinnest.
• D. Right ventricle pumps to lungs at lower pressure than systemic circulation, so walls are thicker than atria but thinner than left ventricle.

Final answer: B