Which is the thick middle muscle layer of the heart?

Which is the thick middle muscle layer of the heart?

• A. Myocardium
• B. Endocardium
• C. Epicardium
• D. Serous Fluid

Answer: (A)

The heart wall has three layers, and the thick middle muscular layer is the myocardium. This layer is made of cardiac muscle tissue that contracts to pump blood with each beat. The inner lining is the endocardium, which covers the chambers and valves, while the outer layer is the epicardium (the visceral layer of the pericardium). Serous fluid sits in the pericardial cavity to reduce friction between the heart and surrounding membranes, not as a tissue layer. The myocardium’s strength is greatest in the left ventricle, which must generate high pressure to push blood through the systemic circulation, while the right ventricle has a thinner muscular wall.

The heart wall has three layers, and the thick middle muscular layer is the myocardium. This layer is made of cardiac muscle tissue that contracts to pump blood with each beat. The inner lining is the endocardium, which covers the chambers and valves, while the outer layer is the epicardium (the visceral layer of the pericardium). Serous fluid sits in the pericardial cavity to reduce friction between the heart and surrounding membranes, not as a tissue layer. The myocardium’s strength is greatest in the left ventricle, which must generate high pressure to push blood through the systemic circulation, while the right ventricle has a thinner muscular wall.