NEET BIOLOGY

Detailed explanation-1: -Intercalated discs are part of the cardiac muscle sarcolemma, so they also contain gap junctions for depolarization between muscle fibers and desmosomes that hold the fibers together during cardiac muscle contraction (Fig. 3b).

Detailed explanation-2: -Intercalated discs are located at the longitudinal ends of cardiomyocyte to form cell–cell coupling critical in propagation of action potentials. Both Cx43 gap junctions and voltage-gated sodium channels are present at intercalated discs.

Detailed explanation-3: -So, the correct option is ‘Cardiac muscles’.

Detailed explanation-4: -Intercalated discs ensure that the cardiac muscle functions as a single and well-coordinated unit. They hold and bind the cardiac muscle cells through fascia adherens and desmosomes, and ensure that the contractile force is transmitted from one cardiac muscle cell to another.