And this space between the visceral and the parietal layer of the inner pericardium is known as the pericardial space or the pericardial cavity. And this contains the pericardial fluid and that fluid lubricates our heart, decreasing the friction that the heart feels every time it actually contracts. So together these two layers of the pericardium protect the heart. They attach the heart to other parts of the body and they lubricate the heart. Now let's move on to the actual heart itself. So if we examine this red segment of the heart, this segment actually consists of three individual layers.