Anatomy & Physiology I and II

Anatomy & Physiology Study Guide

The Heart Wall The wall of the heart in dissection reveals three distinct layers: an outer epicardium, a middle myocardium, and an inner endocardium. • The epicardium covers the outer surface of the heart as the visceral pericardium. This serous membrane consists of an exposed mesothelium and an underlying layer of loose areolar connective tissue that adheres to the myocardium. • The myocardium defines the muscle layer that forms the bulk of both atria and ventricles. This layer contains cardiac muscle tissue, blood vessels, and nerves. The cardiac muscle tissue consists of concentric layers. Muscle bundles that form figure eights wrap around the atria and encircle the great vessels within the atrial myocardium. Superficial cardiac muscles wrap around both ventricles; deeper muscle layers spiral around and

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