Which term is used to describe the outer layer of the cardiac tissue which protects the surface of the heart against trauma or infection?

The outer layer of cardiac tissue that serves the specific purpose of protecting the heart's surface against trauma and infection is known as the epicardium. The epicardium is a thin membrane that forms the outer layer of the heart wall and is made up of connective tissue and fat, which helps to provide cushioning and support for the heart.

Additionally, the epicardium also plays a role in the function of the heart by containing blood vessels that supply the heart muscle and by providing a smooth surface that allows for the efficient movement of the heart within the pericardial cavity. It is important to distinguish this layer from others: the endocardium lines the inner chambers of the heart and is involved with the heart’s function rather than structural protection; the myocardium is the thick, muscular middle layer responsible for contracting and pumping blood; and the pericardium is the fibrous sac that encloses the heart, providing protection and facilitating movement, but is not a layer of the heart tissue itself. Therefore, the term that accurately describes the outer protective layer of the heart is indeed the epicardium.