The blood flow starts in the right atrium to the tricuspid valve, right ventricle, pulmonary valve, pulmonary artery, left and right lung where it gets oxygenated, to the pulmonary veins, left atrium, bicuspid valve, left ventricle, aortic valve, aorta, upper and lower body where it gets deoxygenated, through the superior and inferior vena cave to start again at the right atrium.