Final answer:
Cardiac muscle cells are known for their synchronous responses facilitated by gap junctions, which are critical for the heart's pumping function.
Step-by-step explanation:
Cells with synchronous responses that are facilitated by gap junctions are most notably seen in cardiac muscle cells. Gap junctions allow the electrical signals that initiate contraction to pass quickly from one cell to the next, enabling the heart muscle cells to contract in unison. This well-coordinated contraction is critical for the heart's function as a pump. While other cells may also have gap junctions, they are not characteristic for their synchronous activity in the same way as they are in cardiac muscle.