Arrange the heart wall layers from outermost to innermost.

Arrange the heart wall layers from outermost to innermost.

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

Answer: (A)

The heart wall is organized in three concentric layers from outside to inside: the epicardium, the myocardium, and the endocardium. The epicardium is the outer surface of the heart, and it’s also the visceral layer of the serous pericardium. The middle layer, the myocardium, is the thick, muscular wall that contracts to pump blood. The innermost lining is the endocardium, a thin layer of endothelial tissue that lines the heart chambers and covers the valves. It’s important to note that the pericardium surrounds the heart as a protective sac and is not counted as part of the heart wall itself, which is why including it would be incorrect. This sequence—epicardium, then myocardium, then endocardium—is the correct outer-to-inner arrangement.

The heart wall is organized in three concentric layers from outside to inside: the epicardium, the myocardium, and the endocardium. The epicardium is the outer surface of the heart, and it’s also the visceral layer of the serous pericardium. The middle layer, the myocardium, is the thick, muscular wall that contracts to pump blood. The innermost lining is the endocardium, a thin layer of endothelial tissue that lines the heart chambers and covers the valves. It’s important to note that the pericardium surrounds the heart as a protective sac and is not counted as part of the heart wall itself, which is why including it would be incorrect. This sequence—epicardium, then myocardium, then endocardium—is the correct outer-to-inner arrangement.