It starts at Superior and Inferior vena cava, to Right atrium, Tricuspid valve, Right ventricle, Pulmonary valve, to Pulmonary trunk, to Left and Right artery, to both lungs, to Right and Left pulmonary veins, to Left atrium, Mitral valve, Left ventricle, Aortic valve, to Aorta, to body back to Superior and Inferior vena cava.