Pericardium. We probably don't realize the complete function of pericardium but among others -- we know that pericardium plays a major role in the hemodynamics of the organs -- in this case the heart and the lungs, the fluid exchange and the intrathoracic pressure regulation pertaining to that internal organs -- ad mechanical protection to the heart against trauma, infection, and metastasis --.
See below. The pericardium protects the heart from overfilling but, like the gall bladder and appendix, you can get by without one very well.
Pericardium. Read this: http://en. Wikipedia. Org/wiki/Pericardium.