Intercalated disc is present in

CARDIAC MUSCLE - With the light microscope the junctions between adjoining cardiac myocytes are seen as dark staining transverse lines running across the muscle fibre. These lines are called intercalated discs. Sometimes these discs do not run straight across the fibres, but are broken into a number of 'steps' . The discs always lie opposite the I bands. Cardiac muscle is involuntary and is innervated by autonomic fibres (in contrast to skeletal muscle that is innervated by cerebrospinal nerves). Nerve endings terminate near the cardiac myocytes, but motor end plates are not seen. REF : Inderbir Singh's Textbook of Human HistologY, seventh edition, pg.no.,122.