A tough double-layered sac that surrounds the heart, anchoring it and reducing friction during each beat.
Structure
The sac has a tough outer fibrous layer fused to the diaphragm below and a smooth serous layer that produces a thin film of fluid. The serous layer doubles back over the heart as the epicardium.
Function
A small volume of pericardial fluid, normally about 20 to 50 milliliters, allows the chambers to slide freely with each heartbeat.
Clinical note
Rapid bleeding into the pericardial sac compresses the heart in a condition called cardiac tamponade, which is a medical emergency.
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Pericardial Sac starts with P and ends with C. Browse other body parts along the same letter.
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