Cardiac Muscle Tissue

Cardiac muscle tissue occurs only in the heart. Its cells are joined end to end. The resulting fibers are branched and interconnected in complex networks. Each cell has a single nucleus. At its end, where it touches another cell, there is a specialized intercellular junction called an "intercalated disc," which occurs only in cardiac tissue. Cardiac muscle is controlled involuntarily and, in fact, can continue to function without being stimulated by nerve impulses. This tissue makes up the bulk of the heart and is responsible for pumping blood through the heart chambers into the blood vessels.