3D printable model of anatomic Human Heart without texture. The model is good for education purposes. The human heart is an organ that provides a continuous blood circulation through the cardiac cycle and is a vital organ in the human body. The heart is divided into four main chambers: the two upper chambers are called the left atrium and the right atrium and the two lower chambers are called the right and the left ventricle. There is a thick wall of muscle separating the right side and the left side of the heart called the septum. Normally with each heartbeat, the right ventricle pumps the same amount of blood into the lungs that the left ventricle pumps out into the body. Physicians commonly refer to the right atrium and right ventricle together as the right heart and to the left atrium and left ventricle as the left heart.