What is the function of the pericardial sac?

The pericardial sac serves the important function of enclosing the heart. This double-walled structure provides a protective barrier that helps to safeguard the heart from physical trauma and infections while also allowing enough space for the heart to beat and function properly. The pericardial fluid within this sac helps to reduce friction as the heart expands and contracts, facilitating smooth movement during each heartbeat. By maintaining a protective environment, the pericardial sac plays a crucial role in ensuring the heart operates efficiently without external interference.

The other functions listed, such as pumping blood, generating electrical signals, or providing nutrients, are carried out by different structures within the cardiovascular system. The heart itself is responsible for pumping blood, the conduction system generates electrical impulses, and blood vessels deliver nutrients. Therefore, the specific role of enclosing and protecting the heart is what uniquely characterizes the pericardial sac.