What does the pericardium do?

The pericardium is indeed a double-layered membrane that surrounds the heart. It plays a crucial role in protecting the heart and providing it with a certain level of stability within the thoracic cavity. The two layers of the pericardium, known as the fibrous pericardium and the serous pericardium, help to reduce friction from the heart's movement as it beats and facilitates the heart's motion by allowing it to fill and contract without hindrance.

One of the key functions of the pericardium is to prevent excessive movement of the heart within the chest and to protect it from infection and inflammation that could arise from surrounding structures. The serous layer also secretes a small amount of fluid that acts as a lubricant, which further assists in this process.

This structure is critical for maintaining heart health and function. While other options mention different aspects of cardiac function and anatomy, they do not accurately describe the pericardium itself. The muscle layer associated with the heart is known as the myocardium, the inner lining is referred to as the endocardium, and the separation of the heart chambers is carried out by the septum, rather than being a function of the pericardium.