Written by the Fiveable Content Team • Last updated September 2025
Written by the Fiveable Content Team • Last updated September 2025
Definition
The epicardium is the outermost layer of the heart wall. It provides a protective layer and is also known as the visceral layer of the serous pericardium.
5 Must Know Facts For Your Next Test
The epicardium consists primarily of connective tissue and fat.
It contains blood vessels, nerves, and lymphatics that supply the heart muscle (myocardium).
The epicardium plays a crucial role in producing pericardial fluid to reduce friction between the heart and surrounding structures during heartbeat.
It is continuous with the inner lining of the pericardial sac.
Damage to or diseases affecting the epicardium can influence overall heart function and may lead to conditions such as pericarditis.
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Related terms
Myocardium: The middle muscular layer of the heart wall responsible for contracting and pumping blood.
Endocardium: The innermost layer of the heart wall that lines the chambers and valves, providing a smooth surface for blood flow.
Pericardium: A double-walled sac containing the heart and roots of great vessels, consisting of an outer fibrous layer and an inner serous membrane.