Final answer:
The gap junctions in cardiac muscle are located in the intercalated discs, which are specialized structures that support synchronized muscle contraction. These gap junctions allow the depolarizing current to flow between adjacent cardiac muscle cells.
Step-by-step explanation:
The gap junctions in cardiac muscle are part of specialized cell junctions that are localized to the intercalated discs. Intercalated discs are critical structures that support the synchronized contraction of cardiac muscle. They contain gap junctions that allow the depolarizing current to flow from one cardiac muscle cell to the next, facilitating the quick transmission of action potentials and the coordinated contraction of the entire heart.