Now, there are two main types of arrangements of our muscle cells inside the human body. One of these arrangements is known as the single unit smooth muscle, also known as the visceral smooth muscle. And the other type of arrangement is known as the multi unit smooth muscle arrangement. 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.