Which vessel brings oxygenated blood to the left atrium and is the only vein to carry oxygenated blood?

• A. Pulmonary Artery
• B. Pulmonary Vein
• C. Aorta
• D. Vena Cava

Answer: (B)

Oxygenated blood returning to the heart from the lungs travels through the pulmonary veins into the left atrium. This makes them unique among veins, because most veins carry deoxygenated blood back to the heart. The lungs add oxygen in the pulmonary circulation, so after oxygenation the blood must return to the heart to be pumped to the body, which happens via the pulmonary veins into the left atrium. From there it moves to the left ventricle and then to the body through the aorta. There are four pulmonary veins, two from each lung, entering the left atrium. In contrast, the pulmonary artery carries deoxygenated blood from the right ventricle to the lungs, the aorta transports oxygenated blood from the left ventricle to the body, and the vena cavae return deoxygenated blood to the right atrium.