We're going to look at ligand gated ion channels, we're going to look at voltage gated ion channels and also discuss gap junction. So in this lecture, I'd like to introduce these three different types of channels. And in the following lectures, we're actually going to focus on the details of each one of these channels. And let's begin with the ligand gated ion channel. Now, this is basically a channel, a transmembrane protein that allows the flow of different types of ions. So sometimes we have sodium, we can have potassium, we can have chloride calcium.