Blood from the pulmonary veins enters the:

• A. Left Atrium
• B. Right Atrium
• C. Left Ventricle
• D. Right Ventricle

Answer: (A)

Blood that has been oxygenated in the lungs returns to the heart through the pulmonary veins and enters the left atrium. The left atrium is the chamber that collects this oxygen-rich blood from the lungs before it moves into the left ventricle to be pumped out to the rest of the body. This pathway is distinct from the other chambers: the right atrium receives deoxygenated blood from the body, the right ventricle sends blood to the lungs, and the left ventricle receives blood from the left atrium to power systemic circulation. The pulmonary veins are notable because they bring oxygenated blood back to the heart, not away from it.