Nuclei - cells have a single or occasionally two centrally located nuclei
Intercalated Discs - specialized junctions that connect the individual cells. They are usually unstained, but occasionally appear as thin, dark line between adjacent cells. The intercalated discs are perpendicular to the direction of muscle fibers. They are best seen when stained with phospho-tungstic acid (MH 056 Muscle Types).
Lipofuscin Pigment - residue of lysosomal digestion that accumulates as yellow-brown granules near the nucleus of some cells.
Cardiac muscle does not contain cells equivalent to the satellite cells of skeletal muscle.