What is the term for the sac that encloses the heart?

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

Answer: (A)

The term for the sac that encloses the heart is the pericardium. This protective, double-walled sac surrounds the heart, helping anchor it in the chest and reducing friction as the heart beats with a small amount of lubricating fluid between its layers. The outer fibrous pericardium provides stability, while the serous pericardium (with parietal and visceral layers) lines the sac and covers the heart’s surface. By contrast, the myocardium is the heart’s muscular wall, the endocardium lines the interior chambers, and the aorta is the main artery carrying blood away from the heart.