As of 2015, a three-dimensional diagram of the heart can be found on the Inner Body website. It has an interactive feature for the different sections of the heart, as well as arteries, veins, and valves connecting to the heart.
Each section of the diagram can be clicked on to bring up additional, more detailed views of the heart and its structures. The heart has four chambers: the left and right atria on top, and left and right ventricles on the bottom. Unoxygenated blood enters the heart through the superior and inferior vena cava into the right atrium. It is pumped into the right ventricle and to the lungs to become oxygenated. Oxygenated blood is returned to the heart through the pulmonary veins to the left atrium. It its then pumped to the left ventricle and out of the heart via aortic valve.