Research Paper on Muscles

Abstract
The study of vertebrate skeletal muscles shows that they have many similar features with the Crustacean muscles, though there are few differences. Crustacean muscles of a crayfish show that as the weight of the body increases, the volume of the muscles in the abdomen increases in a direct proportion. Sometimes, crustacean muscle fibers do not function the same way as other vertebrates. For example, as the length of sarcomere increases, the length of the crustacean muscle fibers also increases. During ontogeny, there must be a constant increase in range for both myosin filaments along with actin filaments to lengthen the sarcomere muscles.

Various fibers are typical in all crustacean muscles. These fibers cannot be put in one category because they have some different features; therefore, they lead to the classification of different groups. Sarcomeres are generally known for their function information of tissue units. The purpose of the research to be carried out will be to describe the relationship between sarcomere width and MHC in muscle fibers. Various factors determine fiber types in crayfish abdominal muscles. This is because, in the abdomen of a crayfish, the extensor muscles have multiple types of fiber that function differently. Some fibers are slow while others function fast depending on the biological or chemical phenotypes.

Correlation between Sarcomere Width and MHC in Muscle Fiber
Introduction
Crustacean muscles show a wide range of features, structures, and physiological abilities. Slow fibers contain wide sarcomeres while fast fibers have narrow sarcomeres. The narrow sarcomeres create a sufficient condition for speedier contraction of the muscles. Myosin heavy chain (MHC), and with sarcomeres are the main determinants of contraction rate (Medler & Mykles, 2015). In decapods crustaceans, the kind of muscle fibers is higher than in mammal muscles.

Membrane Potential
The study of cells shows that there is a difference in electrical potential between the intracellular fluid that surrounds a cell and the inside area of the cell. This difference is known as the membrane potential. Though membrane potential is necessary for all cells, it is more important in the cells of the muscles and nerves (Williams & West, n.d.). The necessity is due to coding and transmission of information as a result of changes in membrane potential variations (Perry et al., 2009). An electric potential occurs where a clear separation exists between two locations.

A resting membrane potential occurs when the muscle cell is inactive. To create a resting membrane potential, the membrane only requires separating a few ions, which could either be positive or negative. The two useful factors cause the ions to move. They include the concentration gradient and electrical potential variance. In the case of uncharged molecules, the concentration gradient is applied. An electrical potential is used when the ions are present (Leonard, DuVall, & Herzog, 2012). Both causes can be applicable in the same or different direction of membrane movement.

Sarcomere Width
A sarcomere is the main component of muscles that causes repetition of useful elements. Skeletal muscles contain muscle cells that are tubular in nature. They are known as muscle fibers and are made using a method referred to as myogenesis. Some myofibrils are confined in muscle fibers repetition of portions of sarcomeres resulting into formation of myofibrils (Whiteley et al., 2010). Sarcomere appears when the muscles either relax or contract. They contain fibrous proteins that look as long with some threads that slip past one other. (Perry et al., 2009). The most critical filaments include the myosin and actin. The thick filaments are formed by myosin while the actin forms thin threads.

Myosin connects to the actin through a stringy tail and around the head. Myosin also combines with the chemical substances (ATP) which provides energy to enable a muscle to move. Calcium ions are vital in binding myosin and the actin. When measuring sarcomere, the thick filaments are placed between the thin threads. The sarcomere is then defined on both split ends (Caputo et al., 2008). The areas with the thin filaments are supposed to appear transparent, while the regions with thick filaments should appear optically dense (Vega, 2008). The dark sections represent the thick filaments.

MHC
Major histocompatibility complex is found in vertebrates and is crucial for the acquired immune system. Its function is to determine any foreign molecule and to bind to antigens resulting from pathogens. MHC is necessary for animals and humans in the process of organ transplant (Picard et al., 2011). Each molecule of MHC represents a particular portion of a protein known as an epitope (Pandorf et al., 2009). The amount of MHC works as a measuring agent to show protein balance in a cell.

Research Problem
The research is meant to analyze the correlation between sarcomere widths and the MHC in single muscle fibers. Sarcomere becomes short as muscles contract to move together. As the muscles move, Z disk lines move along. The discussion will also analyze the effects of the muscular movements in vertebrates. The myosin heavy chain will be considered because it affects the flow of the muscle pattern since it is a motor protein.

Literature Review
According to the recent studies, some crustacean muscles have adaptations that enable them to generate their force and store some energy for future use. The most significant feature of muscle fiber is its diameter (Longo the & Diaz, 2013). Electron microscopy has been used in various studies to analyze different categories of fibers such as tonic and phasic (Koyama et al., 2010). Phasic fibers have been found to contain sarcomeres, which are about 4.5 micros regarding length (Friedrich et al., 2010). A wide range of studies indicates that crustacean muscles are present in all categories of arthropods.

Methods
The first step will include preparing the muscle through dissection.
Materials required will include crayfish, ice, ice bucket, and dissecting tools.

• The first step will be to determine the sex and weight of the sample.
• Afterward, the specimen will be placed in crushed ice and the abdomen separated from the thorax.
• An articulating membrane that joins the chest and abdomen will be cut to save the abdomen of the fish. Cut along both sides of the lower abdomen.
• Remove the central portion of the shell using forceps without destroying abdominal muscles.
• Remove the deep flexor muscles carefully.

Procedure
After dissection, the resting membrane potential will be measured using different levels of Potassium.

• Individual muscle fibers will be measured using intercellular electrodes.
• Sarcomere width will then be taken in different abdominal extensor muscles. Then, it will be determined how different myosin isoforms are expressed in single muscle fibers by using SDS-PAGE gels.
• Finally, the correlation between the sarcomere widths and Myosin heavy chains (MHC) in single muscle fibers will be confirmed.

Results
Considering the muscle and its surrounding region as the main factors, deep extensors’ membrane potential should be riskier than the superficial extensor. Using the measurements of different fibers, an individual thread is expected to range of between -45 mV to -80 mV. This means that different sections of Extensor muscle affect the tension in muscle in different ways. When the concentration is high, the average resting potential is more favorable compared to when the level is lower. Low concentration of potassium, therefore, means that the resting potential is less than when the level is high. In sarcomere measurement, the length of superficial extensor muscle can range between 5 and 8. It is observed that deeper fibers are faster than those close to the surface.

Discussion
The correlative factor of MHC as expected in different fibers means that there is a connection that exists between various kinds of neurons in crayfish tissues and the myosin muscles. Heavy chain components are those structure-function correlations that result from task closer with extensor muscles of crayfish and other species of crustaceans (Jimenez, Dillaman, & Kinsey, 2013). Regarding force generation, sarcomere width shows that distal fibers do not contribute much compared to the central fibers. Proximal threads are crucial for alignment of abdominal muscles, and they add much in the generation of force.

Conclusion
This research will make it easy to understand some complicated fibers that are commonly found in the abdominal extensor muscles. An examination of different types of crayfish fibers will generate the best results because it contains different anatomical and physiological roles. Long sarcomere leads to the slowing of contraction of the muscles. Potassium ions are the best in measuring the resting potential because they result in an inverse relationship. In all the procedures involved, there must be a significant difference which will make it possible to observe different changes.

References
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