Postsynaptic cells of the neuronal system are those positioned after the synaptic cleft. These cells usually feature acetyl choline receptors and ligand gated Na+ channels. In the event of acetyl choline reception, an action potential is then propagated down the axon of the cell, if it surpasses threshold potential. This can be prevented if an inhibitory chlorine channel is activated. Postsynaptic cells can be part of either a converging system (one with multiple inputs) or a divergent system (one of many outputs).