Understanding Skeletal Muscle Contraction Physiology Essay

Understanding Skeletal ponderousness Contraction Physiology Essay instaurationmuscular tissue compressions atomic number 18 a result of the buildup of tension in spite of appearance the brawniness, and for musculuss to contract, they must(prenominal) have a continuous supply of forcefulness in the human body of a molecule called adenosine triphosphate or ATP (Silverthorn, D.U., 2010). Through heft contractions, we argon able to run, walk, lift, push, sit, and even chew our food (Stabler, et.al, 2009). In addition to an energy requirement, skeletal hefts must be stimulated to contract (Stabler, et.al, 2009). Skeletal passs are stimulated from an action capableness that originates from within motor neurons (Stabler, et.al, 2009). Motor neurons are those that send galvanising signals to skeletal ponderousness cells (Stabler, et.al, 2009). An action potential is the galvanizing signal that occurs when positively charged ions flood into the motor neuron as a result of a chemical, electric, or other type of input signal (Stabler, et.al, 2009). This signal, an area of intracellular positivity, self propagates down the length of the neuron towards the muscle cell (Silverthorn, D.U., 2010). Once this signal reaches the muscle cell, it is converted into a muscle contraction through a process called excitation-contraction coupling (Stabler, et.al, 2009). The interior of muscle cells also becomes very positive resulting in a muscle contraction.Muscle contractions have 3 different phases which include the potential period, contraction phase, and the laxation phase (Silverthorn, D.U., 2010). The possible period occurs between the start of an action potential and the beginning of a muscle contraction (Stabler, et.al, 2009). This is the phase that leave alone be studied later. The contraction period begins at the end of the latent period and ends when muscle tension ends (Stabler, et.al, 2009). The relaxation period occurs begins at the end of the contr action period until the muscle becomes free of tension (Stabler, et.al, 2009). To initiate a muscle contraction, the comment must reach its doorstep. This is the minimal input signal require to take the action potential within a muscle cell causing the internal cellular environment to become positive (Stabler, et.al, 2009). In addition, the shift in remark fervor can play a use of goods and services in how strongly the muscle gene regularises pull back when it contracts which is referred to as the combat-ready force (Stabler, et.al, 2009). As a input signal is repeatedly applied to a muscle, labor will eventually occur. become flat can refer to a famine in muscle functioning or a gradual radioactive decay in the force sustained by a muscle (Enoka and Duchateau, 2008). some other research has shown that fatigue could be the result of metabolic potpourris that occur within the contractile mechanisms within the muscle fibers such as changes in ion concentrations (Alle n and Westerbland, 2001).If the latent period length is dependent upon the strength of the stimulus, change magnitude the electrical stimulus intensity should also increase the latent period, and since a doorway stimulus needs to be reached for a contraction to occur, then there will be a minimal amount of electrical stimulation required to generate a muscle contraction. In addition, if the active force strength is dependent upon the strength of the stimulus intensity, an increase in stimulus intensity should increase the active force. If muscle fatigue is occurring due to repeated stimuli all over a period of time, then applying a stimulus at a regular rate should result in a decrease of sustainable force within the muscle. These experiments will be carried out using an electrical stimulus by passing a known amount of potency through an isolated skeletal muscle attached to a metallic element holder that will transmit the selective information to a recorder and an range scre en for analyses (Stabler, et.al, 2009)Materials and MethodsIn order to understand muscle contraction physiology, I evaluated 4 different experiments. The first 3 experiments were designed to use a mavin stimulus to evaluate the latent period of a muscle contraction, to evaluate the threshold stimulus of a muscle contraction, and to evaluate the personal effects of increased stimulus intensity on a muscle contraction. The 4th experiment was designed to demonstrate the effects of muscle fatigue. The following materials were use for these experiments an isolated skeletal muscle (75mm in length), a metal holder to measure force generated by the skeletal muscle, an background, an electrical stimulator (single and sixfold stimulus), and a info collection box. The first experiment was designed to desexualize the latent period of a muscle contraction. First, the muscle was attached to the metal holder. The electrode from the electrical stimulator was rested on the surface of the mus cle. The electrical stimulator was mystify to 6.0 volts. A muscle contraction was induce by applying a single electrical stimulus using the electrical stimulator. The data generated a tracing on the oscilloscope screen which was used to determine the latent period by selecting the blockage where the flat line began to rise. The data were save using the data collection box. I repeated this experiment using the following voltages 1.0 volts, 3.0 volts, and 10.0 volts. These voltages were used to put through if changes occurred within the latent periods. For the siemens experiment, the data generated was used to determine the threshold voltage. The threshold voltage occurred when the active force measured in grams was great than 0. The equipment pitup was the same as the last experiment, and the electrical stimulator was set to 0.0 volts. At 0.0 volts, the muscle was stimulated and the results observed and recorded using the oscilloscope and data recorder respectively. This exper iment was repeated multiple times by increasing the voltage by 0.1 volts until the minimal threshold voltage was determined. For the third experiment, the effects on muscle contractions due to an increase in the electrical stimulus intensity were explored. Again the same equipment setup was used. The initial voltage was set to 0.5 volts followed by stimulation of the skeletal muscle. The data were observed and then recorded. This experiment was repeated multiple times by increasing each sequent voltage by 0.5 volts. This continued until the data showed there was no change in the increase in active force. For the final experiment, fatigue was induced in the skeletal muscle. The equipment setup for this experiment was similar to the first trine experiments. However, a different electrical stimulator was used which incorporated a multiple stimulus option as well as a single stimulus option. The multiple stimulus option added the ability to start and retrovert the stimulus activity. This experiment was designed so that several stimuli per second were creation applied to the skeletal muscle if so desired. The electrical stimulator voltage was set to 7.0 volts, and the number of stimuli per second was set to 100. The muscle was then stimulated for somewhat 400 seconds by selecting the multiple stimulus option, and the graphical data were recorded from the oscilloscope.ResultsFor experiment one, the latent period was recorded in milliseconds and was compared to its corresponding stimulus voltage. The time measurement (latent period) reflected the start of the flat line until it began to rise. at a lower place is a summary of the recorded data.Latent Period Determination input signal electromotive force (V)Latent Period (msec)13.8932.78102.22For experiment two, the threshold stimulus determination data was put in by measuring the electrical stimulus voltage and its corresponding active force generated. Once the active force became greater than 0, the experimen t was stopped. Below is a table with the collected data.Threshold DeterminationStimulus Voltage (V)Active Force Generated (gms)000.100.200.300.400.500.600.700.80.02For experiment three, the data were collected in order to determine the effects of increased stimulus voltage on muscle contractions. The data reflected 0.5 volt interval increases in the electrical stimulus until 10 volts were reached. Below is the summary of the data.Muscle Contractions change magnitude Stimulus EffectsMuscle Contractions Increased Stimulus EffectsStimulus Voltage (V)Active Force Generated (gms)Stimulus Voltage (V)Active Force Generated (gms)0.505.51.5910.1561.651.50.436.51.720.6671.742.50.877.51.7831.0481.813.51.198.51.8241.3291.824.51.429.51.8251.51101.82For experiment four, data was graphed in order to demonstrate the effects of fatigue. The rate of the multiple stimulus was 100 stimuli/second at a constant setting of 7.0 volts. The data were recorded over a 400 second interval. Below is a graphic al representation of the collected data.Muscle Fatigue Effects of Prolonged Stimuli Over Time (Stabler, et.al, 2009)CSheas StuffHuman PhysiologyFatigue.jpgCitationsAllen, D.G. and H. Westerbland. (2001). Topical go over Role of phosphate and calcium stores inmuscle fatigue. Journal of Physiology 536.3 657-665.Enoka, R. and J. Duchateau. (2008). Muscle Fatigue what, why and how it influences muscle function.Journal of Physiology 586.1 11-23.Silverthorne, D.U. 2010. Human Physiology An Integrated Approach. fifth Edition. PearsonBenjamin Cummings, pp. 408-422.Stabler, T., Smith, L., Peterson, G., and Lokuta, G. 2009. PhysioEx 8.0 for Human Physiology Laboratory Simulations in Physiology. pp. 17-22.