oxygen rich blood from the lungs goes to the left side of the heart. first through the left atrium and then to your left ventricle. from there it is pumped to the rest of your body through the aorta. the oxygenated blood moves through your body where oxygen is lost and carbon dioxide is gained. the deoxygenated blood returns to your heart through the right atrium and is pumped back to your lungs from the right ventricle. when the blood gets to the lungs it collects oxygen and releases CO2, starting the process again
