Which vein carries oxygenated blood from the lungs to the left atrium?

• A. Superior vena cava
• B. Pulmonary vein
• C. Inferior vena cava
• D. Coronary sinus

Answer: (B)

In pulmonary circulation, blood becomes oxygenated in the lungs and then returns to the heart through the pulmonary veins. These veins uniquely carry oxygen-rich blood and deliver it to the left atrium, where it moves on to the left ventricle and out to the systemic circulation. The other vessels mentioned have different roles: the superior and inferior vena cavae and the coronary sinus bring deoxygenated blood back to the right atrium, from the body or heart muscle, while the pulmonary artery carries deoxygenated blood from the right ventricle to the lungs. So the vein that carries oxygenated blood from the lungs to the left atrium is the pulmonary vein.