Cardiac muscle cells are relatively small and usually have a single, centrally placed nucleus. Cardiac muscle tissue is found only in the heart.

The differences between Cardiac Muscle and Skeletal Muscle

Like skeletal muscle fibers, cardiac muscle cells contain an orderly arrangement of myofibrils and are striated, but significant differences exist in their structure and function. The most obvious structural difference is that cardiac muscle cells are branched, and each cardiac cell contacts several others ta specialized sites called intercalated discs. These cellular connections contain gap junctions that allow the movement of ions and small molecules and the rapid passage of actions potentials from cell to cell, resulting in their simultaneous contraction. Because the myofibrils are also attached to the intercalated discs, the cells "pull together" quite efficiently.