So let's begin by defining what a single unit smooth muscle is. So basically, this is the most common type of arrangement of smooth muscles inside our body. So single unit smooth muscles consist of an innervating neuron that basically innervates a single or several cells in a group or a collection of cells as shown in the following diagram. So we have a single neuron, the axon. The axon splits into these two sections, these two groups. And only one of these cells, this cell here and this cell here, is actually innervated by that neuron.