The heart is enclosed by a membrane called what?

• A. Pericardium
• B. Endocardium
• C. Pleura
• D. Peritoneum

Answer: (A)

The protective sac around the heart is called the pericardium. It forms a double-walled membrane that surrounds the heart and anchors it in the mediastinum. The pericardium has an outer fibrous layer and an inner serous layer that creates a small fluid-filled cavity, which cushions and lubricates the heart as it beats. This setup keeps the heart in place, reduces friction, and helps prevent overexpansion when blood volume changes. The other terms refer to different body linings: the endocardium lines the inside of the heart chambers, the pleura surrounds the lungs, and the peritoneum lines the abdominal cavity.