This slide contains a section of cardiac muscle, which is striated like skeletal muscle but adapted for involuntary, rhythmic contractions like smooth muscle. Although the myofibrils are transversely striated, each cell has only one centrally located nucleus. Note the faintly stained transverse bands,
which are called intercalated disks, (indicated by the blue
arrows) that mark the boundaries between the ends of the cells. These specialized junctional zones are unique to cardiac muscle.