Cardiac muscle cells are connected to neighboring cells at specialized cell junctions called intercalated discs
Features of intercalated discs
plasma membranes of two cardiac muscle cells are bound together by desmosomes
intercalated discs posses specialized junction termed fascia adherens with actin filaments and plasma membranes
cardiac muscle cells are connected by gap junctions (communicating junctions) when ions move
Because cardiac muscle cells are mechanically, chemically, and electrically connected to one another, cardiac muscle tissue functions like a single, enormous muscle cell
The contraction of one cell will trigger the contraction of others so it spreads through myocardium, which is why it is called the functional syncytium