Pericardium - definition and function
What is Pericardium, definition and function
Pericardium is a tough, two-layer membranous sac that encloses the HEART. The pericardium’s fibrous outer layer, called the fibrous pericardium, protects the heart from contact with the chest wall and other structures in the chest, including the LUNGS and the sternum. The pericardium wraps completely around the heart, extending around the bases of the great vessels (AORTA, superior and inferior VENA CAVA, pulmonary ARTERY, pulmonary VEIN) as they arise from the heart. Two ligaments attach the top of the pericardium to the back of the sternum. Other ligaments loosely connect the bottom of the pericardium to the DIAPHRAGM. These structures anchor the heart in its place in the chest.
The inner layer of the pericardium is a filmy envelope. Its two surfaces are the parietal pericardium, which contacts the fibrous pericardium, and the epicardium, which covers the MYOCARDIUM somewhat like a wet tissue. Inside the envelope is a watery fluid that lubricates the heart. The inner pericardium forms a nearly frictionless containment field for the beating heart. The pericardium is vulnerable to INFLAMMATION and INFECTION (PERICARDITIS).
For further discussion of the pericardium within the context of cardiovascular structure and function, please see the overview section “The Cardiovascular System.”
See also ENDOCARDIUM; LIGAMENT.
