PATHOLOGY

Detailed explanation-1: -Blood cells pick up oxygen in the lungs. Pulmonary veins carry the oxygenated blood from the lungs to the heart’s left atrium (upper heart chamber). The left atrium sends the oxygenated blood into the left ventricle (lower chamber).

Detailed explanation-2: -Blood circulation begins in the heart. Red blood cells pick up oxygen in the lungs. Blood travels away from the heart and lungs through the arteries (ar-tuh-reez). Red blood cells drop off oxygen to the cells through tiny tubes called capillaries (cap-ill-air-ies).