Which layer is the middle and thickest layer of the heart wall?

Which layer is the middle and thickest layer of the heart wall?

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

Answer: (B)

The middle and thickest layer is the muscular layer that contracts to pump blood. The heart wall has three layers: the inner lining (endocardium), the muscular middle layer (myocardium), and the outer surface (epicardium). The pericardium is the surrounding sac, not part of the heart wall itself. The myocardium lies between the endocardium and epicardium and is thickest to generate the force needed to move blood, especially from the left ventricle. Endocardium is thin, and epicardium is the outer surface, so the muscular middle layer is the best answer.

The middle and thickest layer is the muscular layer that contracts to pump blood. The heart wall has three layers: the inner lining (endocardium), the muscular middle layer (myocardium), and the outer surface (epicardium). The pericardium is the surrounding sac, not part of the heart wall itself. The myocardium lies between the endocardium and epicardium and is thickest to generate the force needed to move blood, especially from the left ventricle. Endocardium is thin, and epicardium is the outer surface, so the muscular middle layer is the best answer.