Pericardium acts as a defence wall for the heart.

Explanation

Pericardium protects the heart. It is double layered peritoneum, having outer fibrous and inner serous pericardium layers. Fibrous pericardium being tough gives protection to the heart. Serous pericardium has two layers, parietal and visceral layer or epicardium. In between these two layers, there is pericardial fluid, which helps to absorb shocks and provide nourishment. In this way pericardium acts as a defence wall.