Heart starts pumping, never really gonna rest,
Four chambers working, yeah, you know it’s doing best,
Right atrium receives that blood low in O₂,
Right ventricle sends it to the lungs, that’s what it do,
Pulmonary artery, yeah it’s heading out fast,
Gas exchange happens, oxygen fills it at last,
Carbon dioxide leaves when you exhale breath,
Keeps your cells alive, that’s avoiding cell death,
Back to the heart through pulmonary vein flow,
Left atrium collects it, now it’s ready to go,