CARDIOVASCULAR SYSTEM Pericardium   Fibrous protective sac enclosing the heart and roots of the great vessels. Serves as a lubricated container in which the different parts of the heart can contract.   Fibrous pericardium – strong fibrous part, firmly attached to central tendon of the diaphragm   Serous pericardium –   has parietal and visceral layers.… Continue reading Cardiovascular system