So inside each one of these vesicles, we have acetylcholine. And as soon as we have a high concentration of calcium, that will cause these vesicles to undergo an exocytotic process and fuse with the membrane and release these neurotransmitters, ouraceetylcholine. Now, as soon as our acetylcholine are released into the space between these two cells, known as our synaptic cleft, they will begin to travel to the membrane of our postsynaptic cell, our muscle cell. Now, on the membrane of the muscle cell, we have these proteins. These proteins are integral proteins. They're channels.