Skeletal and smooth muscle cells show many similarities but also show many differences. These similarities and differences can be seen by looking at the structure and appearance of these cells, their control mechanisms, and the way they contract. When observing both types of cells under a microscope, several differences are evident. First, skeletal muscles are larger than smooth muscle cells (a muscle cell can be up to 100 µm long). They are also multinucleated whereas smooth muscle cells are non-nucleated (Alberts et al, 2002: 961). Furthermore, skeletal muscle cells appear striated, whereas smooth muscle cells do not show this banding pattern; but they are instead smooth and tapered. The absence of this pattern in smooth muscle cells suggests that they consist of a less organized set of contractile fibers (Silverthorn, 2007: 397). This pattern of bands in skeletal muscles is known as a sarcomere. The sarcomere is found in structures called myofibrils that make up skeletal muscle fibers. Various proteins are present within the sarcomere. One of the most significant, myosin is found in the thick filaments of the sarcomere. Although both cells contain myosin, it is important to highlight that smooth muscle cells contain a much lower percentage of myosin than skeletal muscle cells. Despite this, myosin filaments in smooth muscle cells bind to actin filaments in a manner similar to that in skeletal muscle cells; although there are some differences. For example, myosin filaments in smooth muscle cells are saturated with myosin heads so that myosin can slide over tethered actin filaments over longer distances, allowing the smooth muscle cells to stretch further, while in the skeleton… in middle of paper... ... City University of Medicine and Biosciences (online), available at courses.kcumb.edu/fisio/smoothmuscle/eccoupling.htm - Accessed 11/18/2013.6. McFadzean I and Gibson A (2002) “The developing relationship between receptor-driven and store-driven calcium channels in smooth muscle.” British Journal of Pharmacology 135: 1-13. Online, available at http://onlinelibrary.wiley.com/doi/10.1038/sj.bjp.0704468/pdf - Accessed 23/11/2013.7. Vander AJ, Sherman J and Luciano DS (2004) Human Physiology: The Mechanisms of Body Function, 9th edition, McGraw-Hill, New York - Accessed 22/11/2013.8. Becker W. M, Hardin J, Kleinsmith LJ and Bertoni G (2010) Becker's World of the Cell, 8th edition, San Francisco, Pearson Education Inc- Accessed 23/11/2013.9. Berridge MJ (2012) Cell Signaling Biology (online), available at www.biochemj.org/csb/frame.htm- Accessible 23/11/2013.