Skeletal and smooth muscle cells show a number of similarities however they also display many differences. These similarities and differences can be seen through observing the structure and appearance of these cells, their control mechanisms and the ways in which they contract.
When observing both cell types under a microscope several differences are obvious. Firstly, skeletal muscles are larger than smooth muscle cells (one muscle cell can be up to 100µm in length). They are also multinucleated whilst smooth muscle cells are uninucleate (Alberts et al, 2002: 961). Additionally, skeletal muscle cells appear to be striated, whereas smooth muscle cells do not show this banding pattern; but are instead smooth and tapered. The absence of this patterning in smooth muscle cells suggests that they consist of a less organised collection of contractile fibres (Silverthorn, 2007: 397). This banding pattern in skeletal muscles is known as the sarcomere.
The sarcomere is found in structures called myofibrils which make up skeletal muscle fibres. Within the sarcomere there are various different proteins. 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 compared to 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 instance, myosin filaments in smooth muscle cells are saturated with myosin heads so that myosin can glide over bound actin filaments over longer distances, enabling smooth muscle cells to stretch further, whilst in skeleta...
... middle of paper ...
... City University of Medicine and Biosciences (online), available at courses.kcumb.edu/physio/smoothmuscle/eccoupling.htm- Accessed 18/11/2013.
6. McFadzean I and Gibson A (2002) “The developing relationship between receptor-operated and store-operated 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 A.J, Sherman J and Luciano D.S (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 L.J an Bertoni G (2010) Becker’s World of the Cell, 8th edition, San Francisco, Pearson Education Inc- Accessed 23/11/2013.
9. Berridge M.J (2012) Cell Signalling Biology (online), available at www.biochemj.org/csb/frame.htm- Accessed 23/11/2013.
In the beginning phases of muscle contraction, a “cocked” motor neuron in the spinal cord is activated to form a neuromuscular junction with each muscle fiber when it begins branching out to each cell. An action potential is passed down the nerve, releasing calcium, which simultaneously stimulates the release of acetylcholine onto the sarcolemma. As long as calcium and ATP are present, the contraction will continue. Acetylcholine then initiates the resting potential’s change under the motor end plate, stimulates the action potential, and passes along both directions on the surface of the muscle fiber. Sodium ions rush into the cell through the open channels to depolarize the sarcolemma. The depolarization spreads. The potassium channels open while the sodium channels close off, which repolarizes the entire cell. The action potential is dispersed throughout the cell through the transverse tubule, causing the sarcoplasmic reticulum to release
Keiger, D. (2010, June 2). Immortal Cells, Enduring Issues. Johns Hopkins Magazine. Retrieved from http://http://archive.magazine.jhu.edu/2010/06/immortal-cells-enduring-issues/
Muscle fibers are cylindrical. They have a diameter around ten to one hundred micrometers and are generally a few centimeters long. Within each muscle cells, contains basal lamina of collagen and glycoproteins. Each fiber contains a structure called excitation-contraction coupling, which is used to make sure the each contractile stimulus is quickly and equally communicated throughout the muscle fiber.
The Lives of a Cell: Notes of a Biology Watcher by Lewis Thomas consists of short, insightful essays that offer the reader a different perspective on the world and on ourselves.
Zielinski, Sarah. "Henrietta Lacks ' 'Immortal ' Cells." Smithsonian Magazine. Smithsonian, n.d. Web. 11 Nov.
Noe, R. A., Hollenback, J. R., Gerhart, B., & Wright, P. M. (2011). Fundamentals of human
Miller, K. R., & Levine, J. S. (2010). Miller & Levine biology. Boston, Mass.: Pearson.
Dystrophin is part of a complex structure involving several other protein components. The "dystrophin-glycoprotein complex" helps to anchor the structural skeleton (cytoskeleton) within the muscle cells, through the outer membrane (sarcolemma) of each cell, to the tissue framework (extracellular matrix) that surrounds each cell (Straube and Campbell, 1997). Due to defects in this assembly, contraction of the muscle leads to disruption of the outer membrane of the muscle cells and eventual weakening and wasting of the muscle
Skeletal, smooth, and cardiac muscles play a vital role in the everyday processes that allow the human body to function. Without these muscles, everyday tasks and functions could not be conducted. Injury to these muscles could cause serious problems, however, these muscles have the ability to regenerate, repair, and fix multiple problems all by themselves. Repair and regeneration of a muscle are two similar, yet different things. Repair restores muscle continuity so that it can continue to function in the same way as before injury, but does not completely restore the pre-injury structure like regeneration (Huijbregts, 2001). Muscle repair and regeneration take place after an injury, after surgery, after atrophy, and even after working out.
Taylor, Richard. "The Mind as a Function of the Body." Exploring Philosophy. 4th ed. New York: Oxford UP, 2012. 131-138. Print.
VanPutte, C., Regan, J., & Russo, A. (2014). Seeley's anatomy & physiology(10th ed.). NEW YORK, NY: MCGRAW-HILL.
The musculoskeletal system is made up of bones, muscles, cartilage, tendons, ligaments, joints and other connective tissue that supports and binds tissue and other organs together. Each muscle is a discreet organ constructed of skeletal muscle tissue, blood vessels, and nerves. Did you know there are roughly 600 organs that make up the muscular system? They include the cardiac muscles, smooth muscles, and skeletal muscles to name a few. The heart is the cardiac muscle. Smooth muscle are the tissues that line blood vessels and organs, such as the stomach and intestines. The skeletal muscles, which are the most well known and familiar of the muscle organ system, helps hold the skeletal frame work together. They make up bout 40 percent of the
Ross, A. C. (2005). Physiology. In B. Caballero, L. Allen, & A. Prentice (Eds.), Encyclopedia of
Ladies and gentlemen, boys and girls this is never before news! It gives me great pleasure to introduce to you a once in a life time interview with one of the biggest mafia families out here in the great Big Apple (a.k.a New York), the Corleone family. We have taken interviews given to some of the family members throughout the years, and put together a little project. It gives me great pleasure to release this astonishing interview into the science world, which will help scientist and the young children on how to remember the cell and its organelles. Cells are important because we humans are made up of cells, without cells we wouldn’t be anything and wouldn’t be able to function. By telling the members of the Corleone family that these interviews were for science, they graciously accepted my offer and helped me out on how to get a better grasp on the cell and its organelles.
The depolarization is immediately restored by an exchange of ions resulting in repolarization. It’s followed by phase called the ‘after hyperpolarization’ period of the membrane. During this phase, the action potential spreads from the motor endplates, along the muscle fiber, and inside the muscle fiber. The excitation causes calcium ions to be released and the contractile elements of the muscle cell become shortened. This process describes the mechanisms that follow the contraction of a healthy muscle