The Pericardium: (Coverings of the Heart)

• A double-walled sac
• contains a film of lubricating serous fluid
• 2 Layers of Pericardium:
1.    Fibrous Pericardium:
•    Tough, dense connective tissue
•    Protects the heart
•    Anchors it to surrounding structures
•    Prevents overfilling of the heart—if fluid builds up in the pericardial cavity, it can inhibit effective pumping. (Cardiac Tamponade)

2.    Serous Pericardium: (one continuous sheet with ‘2 layers’)
•    Parietal Layer – Lines the internal surface of the fibrous pericardium
•    Visceral Layer – (aka Epicardium) Lines the external heart surface
Layers of the Heart Wall:
1.    Epicardium:
•    Visceral layer of serous pericardium
2.    Myocardium:
•    Muscle of the heart
•    The layer that ‘contracts’
3.    Endocardium:
•    Lines the chambers of the heart (Endothelial Cells)
•    Prevents clotting of blood within the heart
•    Forms a barrier between the O2 hungry myocardium and the blood. (blood is supplied via the coronary system)