Cardiac Muscle Cell EM

In this EM image of a cardiac muscle cell note the same banding pattern to skeletal muscle cells. In cardiac muscle cells, myosin and actin filaments are organized into sarcomeres as in skeletal muscle cells. The dark-staining line is an intercalated disc that connects adjacent cardiac muscle cells. Intercalated disks contain two types of adhesive junctions: fascia adherins and macula adherins. Fascia adherins are similar to adherins junctions in epithelial cells, except they don't form a belt around the cell. Macula adherins are equivalent to desmosomes. Also present are gap junctions that mediate passage of electrical signals between cardiac muscle cells.