We discussed voltage gated on channels and ligand gated on channels. Now, we move on to a slightly different category, vine channels we call gap junctions. Now, gap junctions are also known as cell to cell channels, and we'll see why in just a moment. Now, although gap junctions are in fact on channels, they have very different properties from the properties of voltage gated and ligand gated on channels. And there are five important things that differentiate gap junctions from voltage gated and ligand gated on channels. So let's begin by comparing and contrasting these different types of on channels.