Figure 8b. The path of a typical RBC through the heart: The deoxygenated RBC (1) enters the right atrium (RA) through the superior or inferior vena cava; (2) travels through the tricuspid valve into the right ventricle (RV); (3) continues through the pulmonary valve into the pulmonary artery and into the lungs; (4) returns, oxygenated, through the pulmonary vein into the left atrium (LA) and continues through the mitral valve and into the left ventricle (LV); and (5) flows through the aortic valve into the aorta and back out into the body.