Physio Report

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Physiology 244 Animal practical 1 08/08/2014 Exercise 1 Question 1 The amplitude of the muscle contraction increased as the voltage increased until a threshold was met. Question 2 The smallest voltage that resulted in a contraction would be that of 0.0500V. Only a portion of the muscle fibers contracted at the above mentioned voltage while the other fibers were relaxed. Given the small force produced at this low voltage (0.0370 N) in comparison to that of the voltage that resulted in the largest contraction (0.1940N) less than 20 percent of the fibers contracted at this voltage. Question 3 The smallest voltage that produced the largest contraction would be that of 0.8000V. During this stimulus 100 percent of the muscle fibers…show more content…
At the about the 30 second point there was a sudden sharp increase in the force presumably as the final muscle contraction before the muscle became fatigue. Question 14 The time point the muscle started to decrease was round about the 35 second mark. At this point there was an 85.5 percent decline in force from the maximum force at the end of the stimulation. By the time the muscle reached the fatigue stage less muscle fibers were able to contract and because less fibers contracted, the force needed to contract these fiberes were much less than that of the initial maximal force resulting in the very high percentage of decline in force. Question 15 A possible mechanism that attempt to explain fatigue is the depletion of substrate an the accumulation of product. Limiting Ca2+ and ATP is why the muscle is unable to maintain prolong contraction. ATP is a limiting factor as when there is a decrease in ATP it becomes unavailable to the cross bridges. Ca2+ is responsible for the rate of myosin and actin binding. With limited Ca2+ there is a limited amount of myosin and actin binding therefore there will be a decrease in the force and ultimately the muscle will not be able to contract. Question 16 Yes, as the characteristics of smooth muscle contractions include strong, prolonged contractile activity and low energy requirements. That is to say that the smooth muscle will not undergo
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