Pericardium

The pericardium is a thin, double-walled sac that surrounds and protects the heart. It is made of two layers, an outer fibrous layer and an inner serous layer. Its main function is to provide a barrier between the heart and the other organs in the chest, as well as serve as a lubricant. It also helps to reduce friction from the circulation of blood through the heart and maintains a constant pressure on the heart. The pericardium plays an important role in the prevention of certain diseases including endocarditis, ventricular fibrillation, and atrial fibrillation. Additionally, it is also used in a variety of surgical procedures, such as bypass grafting, cardiac pacemaker implantation and heart valve replacement.