The pericardium is a membranous sac that encloses the heart
Pericardium consists of 2 portions:
The outer, tough, connective tissue fibrous pericardium
The inner, more delicate, double-layered serous pericardium,
which consists of:
Parietal pericardium, the outer layer of the serous membrane, which
lines the inner surface of the fibrous pericardium
Visceral pericardium (epicardium), the inner layer of the serous
membrane, that covers the heart
Pericardial cavity, the space between the visceral and parietal layers,
which contains serous fluid for reducing friction between the layers
Wall of the Heart
The wall of the heart is composed of 3 layers:
Epicardium(visceral pericardium): the outermost layer; a serous membrane made up of connective tissue and epithelium
Myocardium: the middle layer; consists of cardiac muscle, and is the thickest later of the heart wall
Endocardium: the inner layer; made up of connective tissue and epithelium; continuous with the endothelium of major vessels joining the heart