Which of the following is NOT part of the heart?

• A. Lungs
• B. Atria
• C. Ventricles
• D. Pericardium

Answer: (D)

The heart is defined by its internal structures—the atria and ventricles—which are the chambers that receive and pump blood. The pericardium, on the other hand, is the protective membrane that surrounds the heart, forming a sac that anchors and lubricates it. Because the pericardium is not a chamber or tissue that constitutes the heart itself, it is not considered part of the heart. The lungs are also not part of the heart, though they are nearby and work closely with it, their role being in respiration rather than being cardiac components. In this context, the structure that is not part of the heart’s actual composition is the pericardium, since it lies outside the heart’s chambers but envelops them as a surrounding protective layer.