Recall the three layers of muscles in the wall of the heart. Which lists these muscles in order from closest to the blood inside the chamber to farthest from the blood?

From the blood-filled chamber outward, the heart wall is lined by the endocardium, followed by the thick muscular myocardium, and then the outer epicardium. Therefore, the correct order is endocardium, myocardium, epicardium.

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