Which heart chamber receives oxygenated blood from the lungs?

• A. Left ventricle
• B. Left atrium
• C. Right atrium
• D. Right ventricle

Answer: (B)

Oxygenated blood returns to the heart from the lungs and enters the left atrium. The lungs add oxygen to the blood, and this freshly oxygenated blood travels through the pulmonary veins into the left atrium. From there, it moves across the mitral valve into the left ventricle, which then pumps it to the rest of the body via the aorta. The other chambers handle blood from the body or move blood toward the lungs, not directly from the lungs to them: the right atrium and right ventricle deal with deoxygenated blood returning from the body and sending blood to the lungs, and the left ventricle receives blood from the left atrium, not directly from the lungs. So the chamber that receives oxygenated blood from the lungs is the left atrium.