Cardiac Muscle CellsStructure of the cardiac muscle cells allow propagation of stimuli through the heart wall.Overall, cardiac muscle appears to be striated, and the arrangements of myosin and actin are similar to skeletal muscles. Relative to skeletal muscles, cardiac muscle cells are shorter and wider. In most cases, the muscle cells tend to have one nucleus. Also, cardiac muscle is special in that it is not voluntarily controlled.The cardiac cells are Y-shaped and are interconnected in long chains with other cardiac cells. The junction between the connected cells are called intercalated discs. The intercalated discs have double membranes which provide channels to the cytoplasts of other cardiac cells. The cardiac cells are connected by their Y-shaped cells and are electrically connected. This allows for a wave of depolarization, which then leads to a synchronized muscle contraction.