biol 253 midterm SG Exam with precise
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detailed answers 5
1. What are the main causes of fatigue addressed for each of the variables
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tested? (brief periods of rest, encouragement and visual feedback) - Correct
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answer ✔Encouragement: change in motivation/ central drive
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Visual Feedback: sense of effort
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Rest: build-up of lactic acid and a reduction in blood flow
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Encouragement - Correct answer ✔change in motivation/ central drive 5 5 5 5 5 5 5 5
Visual Feedback - Correct answer ✔sense of effort
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Rest - Correct answer ✔build-up of lactic acid and a reduction in blood flow
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What would you expect from a person's EMG who has Muscular Dystrophy
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who is asked to lift a weight? How would that differ from a person with
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Myasthenia Gravis? - Correct answer ✔Muscular Dystrophy: EMG would look
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5the same as a normal individual despite the muscle cell dying, the nerve
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signal is unaffected. 5 5
Myasthenia Gravis: EMG would look weaker and fatigue faster than a normal
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individual.
, Muscular Dystrophy - Correct answer ✔EMG would look the same as a
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normal individual despite the muscle cell dying, the nerve signal is
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unaffected.
Myasthenia Gravis - Correct answer ✔EMG would look weaker and fatigue
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faster than a normal individual.
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The muscle cell doesn't stockpile large quantities of ATP. How does the
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muscle ensure enough ATP is available for intense exercise? - Correct answer
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✔At rest, some ATP transfers a phosphate to creatine and creates
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phosphocreatine. This can be used to resynthesize ATP during intense 5 5 5 5 5 5 5 5 5 5
exercise for the contraction to continue.
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During repeated skeletal muscle contraction, what happens to calcium within
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a single motor unit that may lead to fatigue? What is its overall effect? -
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Correct answer ✔A reduction in Ca2+ ion release (due to depletion of Ca2+
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ions from intracellular stores: the sarcoplasmic reticulum) inhibits excitation-
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contraction coupling. 5
If EMG electrodes were placed on the flexor digitorum superficialis (one of
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the muscles involved in maintaining grip) while applying sustained max force,
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5what would the EMG trace look like as you encounter fatigue for both the
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raw data and the RMS data? - Correct answer ✔
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detailed answers 5
1. What are the main causes of fatigue addressed for each of the variables
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tested? (brief periods of rest, encouragement and visual feedback) - Correct
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answer ✔Encouragement: change in motivation/ central drive
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Visual Feedback: sense of effort
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Rest: build-up of lactic acid and a reduction in blood flow
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Encouragement - Correct answer ✔change in motivation/ central drive 5 5 5 5 5 5 5 5
Visual Feedback - Correct answer ✔sense of effort
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Rest - Correct answer ✔build-up of lactic acid and a reduction in blood flow
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What would you expect from a person's EMG who has Muscular Dystrophy
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who is asked to lift a weight? How would that differ from a person with
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Myasthenia Gravis? - Correct answer ✔Muscular Dystrophy: EMG would look
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5the same as a normal individual despite the muscle cell dying, the nerve
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signal is unaffected. 5 5
Myasthenia Gravis: EMG would look weaker and fatigue faster than a normal
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individual.
, Muscular Dystrophy - Correct answer ✔EMG would look the same as a
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normal individual despite the muscle cell dying, the nerve signal is
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unaffected.
Myasthenia Gravis - Correct answer ✔EMG would look weaker and fatigue
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faster than a normal individual.
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The muscle cell doesn't stockpile large quantities of ATP. How does the
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muscle ensure enough ATP is available for intense exercise? - Correct answer
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✔At rest, some ATP transfers a phosphate to creatine and creates
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phosphocreatine. This can be used to resynthesize ATP during intense 5 5 5 5 5 5 5 5 5 5
exercise for the contraction to continue.
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During repeated skeletal muscle contraction, what happens to calcium within
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a single motor unit that may lead to fatigue? What is its overall effect? -
5 5 5 5 5 5 5 5 5 5 5 5 5 5 5
Correct answer ✔A reduction in Ca2+ ion release (due to depletion of Ca2+
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ions from intracellular stores: the sarcoplasmic reticulum) inhibits excitation-
5 5 5 5 5 5 5 5
contraction coupling. 5
If EMG electrodes were placed on the flexor digitorum superficialis (one of
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the muscles involved in maintaining grip) while applying sustained max force,
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5what would the EMG trace look like as you encounter fatigue for both the
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raw data and the RMS data? - Correct answer ✔
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