Which heart lining forms the inner surface of the heart chambers?

Which heart lining forms the inner surface of the heart chambers?

• A. Endocardium
• B. Epicardium
• C. Myocardium
• D. Pericardium

Answer: (A)

The inner surface of the heart chambers is formed by the endocardium. This thin endothelial lining covers all four chambers and the heart valves, providing a smooth, low-friction surface for blood flow and continuing with the endothelium lining the great vessels. It also has a subendocardial layer that can include conduction tissue in parts of the heart. The epicardium is the outer surface of the heart (part of the serous pericardium), the myocardium is the thick muscular layer that contracts to pump blood, and the pericardium is the fibrous sac surrounding the heart.

The inner surface of the heart chambers is formed by the endocardium. This thin endothelial lining covers all four chambers and the heart valves, providing a smooth, low-friction surface for blood flow and continuing with the endothelium lining the great vessels. It also has a subendocardial layer that can include conduction tissue in parts of the heart.

The epicardium is the outer surface of the heart (part of the serous pericardium), the myocardium is the thick muscular layer that contracts to pump blood, and the pericardium is the fibrous sac surrounding the heart.