The four chambers of the heart are the right atrium, right ventricle, left atrium and left ventricle.Deoxygenated blood (blood with no oxygen) flows into the right side of the heart via the superior and inferior vena cava. The deoxygenated blood then flows through the right atrium and into the right ventricle. The right ventricle pumps blood to the lungs via the pulmonary (lung) artery. The lungs then give the blood oxygen so, the blood is now 'oxygenated'. The newly oxygenated blood is pumped back to the left side of the heart via the pulmonary vein. It flows into the left atrium and then into the left ventricle. The left ventricle pumps the oxygenated blood into the aorta (the big artery). This blood then delivers oxygen to the cells, tissues and organs in the body allowing them to work normally - if it doesn't work properly, these tissues will die.(I would also draw a diagram of the heart and lungs showing how the blood flows through them). I could go into more detail if the student wished.