Let's take a look at our heart. So in our heart, we have these specialized muscle cells we call cardiac myocides, or simply cardiac muscle cells. And these cardiac muscle cells are closely packed, so they are contiguous in nature. And because of that, many of these cardiac muscle cells are connected by these gap junctions. So what's the function of these gap junctions? Well, basically, when one cell receives an action potential as a result of these gap junctions, the action potential can actually propagate into nearby cardiac myosytes.