Remove the pericardium, which is a thin membrane that surrounds the heart, with a blunt probe to expose the structure of the heart more closely. The right side of the heart pumps blood to the lungs, while the left side of the heart pumps blood to all other parts of the body. Locate the right and left sides of the heart. The structures visible on the heart are the two atria, the ventricle which have two chambers. Each side of the heart has an upper and a lower chamber. Upper chambers are called atria and receive blood, while lower chambers are called ventricles and pump blood out of the heart. You can easily locate the right and left atria and ventricle by looking at the heart.