<prompt> Heart muscles act as a functional syncitium because:StriationsGap junctionsLong action potentialIt is voluntary  <response>: Ans: b Gap junctions Ref: Ganong, 22nd ed, p. 78; Guyton, 11th ed, p. 103,104The gap junctions between adjacent cells provide low resistance bridges for the spread of excitation and function it as a functional syncitium even though no protoplasmic bridges are present between the cells.Histological features of cardiac muscle Striated muscle with actin and myosin filaments. The fibers branch and interdigitate. Single nucleus present. Intercalated disc present at the Z lines. Gap junctions are present helping it to act as a functional syncytium. Neural control depends on the pace maker. 