So once again, the heart can be broken down into three layers. So we have our epicardium, we have the myocardium and we have the endocardium. And these three layers form four different chambers inside our heart. So now let's focus on the four different chambers. Now, the entire heart can actually be broken down into two pumps. So if we are examining our body from this image, from this direction, we have the right side and we have the left side.