So in this lecture, we're going to discuss the smallest functional unit of the skeleton muscle and the cardiac muscle known as the sarcomire. So what exactly does the sarcomire actually look like? Well, this diagram basically describes our sarcomir. We have a single sarcomere on this side and the sarcomere is basically lie adjacent to one another and they create long muscle fibers as we'll see in the next several lectures. So we have a single sarcomir here, we have another sarcomere to the right side, we have another sarcome to the left side and so forth. Now, from this diagram, we see we have different regions within our sarcomir.