Example Of Report On Muscle Physiology

Introduction

One of the systems of the body is the muscular system which is has a specific function of either contracting or shortening (Seeley et al 2008). The muscular system has three types namely the skeletal, cardiac, and smooth muscle. Skeletal muscle is a type of muscle tissue that allows movement of the body. Muscle contraction is defined as the process where in muscle fibers produce tension or action potential frequency when there is an interaction among different contractile proteins or sliding of actin over myosin myofilaments which is controlled by the nervous system. Action potential frequency is defined as the total number of action potentials generated by the muscle per unit of time. The contraction and production of action potential of the muscles are affected by the amount of load and tension exerted during a particular task or exercise.
Based on the given facts, will there be an increase in the EMG signals if the amount of workload is increased? Also, will the electrical signal produced by the muscles also increase if the muscle does not shorten? According to the previous lectures, it is most likely that an increase in the amount of work load or the absence of muscle shortening (change in muscle length) will lead to increased amount of EMG signal that will be produced.

Materials and Methods

The laboratory experiment used different amounts of weights and an electromyograph to measure the electrical signal produced by the muscle when lifting a load. To answer the first question, the students conducting the experiment must attachment an electromyograph to the part of the muscle that will be measured and to use the muscle to carry a certain amount of load. The initial voltage produced by the muscle as it carried a certain amount of load should be noted. Next, the amount of workload should be increased after every measurement of the voltage. The different values should be noted because they will be used for plotting values in the graphs. The reliability and validity of the experiment will be increased if it will be done in two to three trials.
On the other hand, the relationship of the length of muscle and the electric signal produced by the muscle can be observed by doing an experiment wherein a person carries a constant load or fixes the muscle at a certain position for a certain amount of time. The graph for the experiment can be done by recording the different values of the electric signals obtained by the electromyograph after every few minutes. If the hypothesis that has been presented is correct, the graph for both of the two experiments should present a linear graph with a positive slope which suggests that there is a direct relationship between the amount of workload and voltage and the amount of workload and length of muscle.

Results

Data showed that an increase in the amount of work load results to an increase in electric signal. Thus, there is a direct relationship between the amount of workload and the amount of electric signal. On the other hand, for isometric contraction, the amount of electric signal also increases even if the muscle does not shorten. Like isotonic contraction, the results showed that there is a direct relationship between the isometric contraction effort and the amount of electric signal produced by the muscle. There is a direct relationship between the isometric contraction effort and the amount of electric signal produced by the muscle.

Discussion and Conclusion

Both types of contraction involve accumulation of tension. However, they are different because isotonic contraction involves changing of muscle length to accommodate the tension exerted by a source to the muscle while isometric contraction does not involve changes in muscle length. The results obtained from the experiment were line with the hypotheses and predictions that have been presented in the first part of the paper. For the first hypothesis, the results supported it by showing a linear graph with a positive slope. The linear graph supports the prediction wherein it has been stated that there is a positive linear relationship between the amount of work load and the amount of electrical signal. Seeley et al (2008) stated that the muscle adapts to the increase in workload by changing the length of the muscle and increasing the number of motor neurons stimulated by the impulses controlled by the nervous system. On the other hand, the results obtained from the second experiment was also in line with the hypothesis presented. Based on the results, increase in effort exerted by the muscle results to increase in electrical signal produced by the muscle even if it does not shorten or change in length. The results and hypothesis were similar because an increase in the amount of electrical signal was presented in the hypothesis and shown in the findings. Thus, based on the results of the experiment and the facts presented by the sources, I can conclude that in isotonic contraction, the amount of electrical signals increases as the amount of workload increases. Similarly, in isometric contraction, the amount of electrical signal also increases as the effort exerted to the muscle increases.

Works Cited

Seeley, Rod, Trent Stephens, and Philip Tate. Anatomy and Physiology. 8th ed. New York: McGraw-Hill Companies, Inc., 2008. Print.
Pictures of the Graph