Now let's look at a portion of our cell membrane found at the exxon hillock. The exxon hillock is simply the portion of the neuron where our signal is generated. But remember, we're talking about the resting potential. That means no signals are being generated just yet. So let's examine the different types of ions that are present within our body, within our cells. So we see that we have calcium, we have potassium, we have sodium, and we have chloride.