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. We have the H zone, we have the A band, we have the Z lines, and we also have something known as the iband, which stretches over to sarcomeres. Now, before we actually discuss what these regions are, let's discuss the composition of our sarcommerce. So what types of proteins are found inside our sarcomir?