Only cardiac muscle has this particular appearance, which is given to it by something called intercalated discs. Cardiac muscle also consists of single muscle cells, called Cardiomyocytes; where something such as skeletal muscle cells are MULTInucleated (more than one cell nucleus).
This photo displays cardiac muscle tissue. This tissue type is striated, branched, and has 1-2 nuclei. Cardiac muscle tissue can be recognized by intercalated disks (dark thickened part). Cardiac muscle cells are bigger than smooth muscle cells and smaller than skeletal muscle cells. They control involuntary movement (the heart).
conduction_system_of_the_heart The cardiac conduction system is a group of specialized cardiac muscle cells in the walls of the heart that send signals to the heart muscle causing it to contract. The main components of the cardiac conduction system are the SA node, AV node, bundle of His, bundle branches, and Purkinje fibers.