intercalated disc

An electron-dense junctional complex, at the end-to-end contacts of cardiac muscle cells, that contains gap junctions and desmosomes. Most of the disc is formed of a convoluted type of adherens junction into which the actin filaments of the terminal sarcomeres insert (they are therefore equivalent to half Z-bands) ; desmosomes are also present. The lateral portion of the stepped disc contains gap junctions that couple the cells electrically and thus coordinate the contraction.