PhysioEx Exercise 2 Activity 2
2/28/22, 8:57 PM
PhysioEx Lab Report
Exercise 2: Skeletal Muscle Physiology Activity 2: The Effect of Stimulus Voltage on Skeletal Muscle Contraction
Name: Zandria
Date: 28 February 2022
Session ID: session-1572cf45-8e58-9511-aa71-e6505aa1b7a1
Pre-Iab Quiz Results
You scored 100% by answering 4 out of 4 questions correctly
1 Skeletal muscle fibers are innervated (stimulated) by
You correctly answered: motor neurons.
You correctly answered: a single action potential and a single contractile event in the
muscle fibers it innervates.
3 In resting skeletal muscle, calcium is stored in
You correctly answered: the sarcoplasmic reticulum
4 During the latent period for an isometric contraction
occur.
Experiment Results
Predict Question
1 Predict Question: As the stimulus voltage is increased from 1.0 volt up to 10 volts, what
will happen to the amount of active force generated with each stimulus?
Your answer: The active force will first increase and then plateau at some maximal value as the stimulus voltage increases
Stop & Think Questions
https://media.pearsoncmg.com/bc/bc_0media_ap/physioex/10/ex2/act2/
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PhysioEx Exercise 2 Activity 2
2/28/22, 8:57 PM
1 What do you observe in the active force display when the stimulus voltage is set to 0.0
and why does this observation make sense?
You did not answer this question.
Correct answer: 0.oo; there was no activation of skeletal muscle fibers by this stimulus
2 What is the lowest stimulus voltage that induces active force in the skeletal muscle?
You correctly answered: threshold voltage
3 Enter the threshold voltage for this experiment.
You did not answer this question.
4 Enter the maximal voltage for this experiment.
You did not answer this question.
Experiment Data
Post-Iab Quiz Results
You scored 100% by answering 6 out of 6 questions correctly.
1 Motor unit recruitment refers to
You correctly answered: an increase in the number of active muscle fibers to increase the force developed in a muscle.
2 Active tension (or force) in a skeletal muscle fiber results from
You correctly answered: activation of cross bridge cycling via increased intracellular calcium levels.
3 The is the minimal stimulus needed to cause a depolarization of the muscle plasma membrane (sarcolemma).
You correctly answered: threshold voltage
4 By definition, the is the amount of stimulus required to successfully recruit al/the muscle fibers into developing active force.
You correctly answered: maximal voltage
https://media.pearsoncmg.com/bc/bc_0media_ap/physioex/10/ex2/act2/
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PhysioEx Exercise 2 Activity 2
2/28/22, 8:57 PM
5 Why was a maximal voltage observed in this experiment?
You correctly answered: At the maximal voltage, all the muscle fibers contained in this
muscle are depolarized and they all develop active force (that is, they were all successfully recruited).
6 A sufficiently strong electrical stimulus applied to an isolated, mounted skeletal muscle induces the development of muscle force, or muscle tension. Which of the following statements concerning this observation is true?
You correctly answered: The electrical stimulus mimics acetylcholine release at a
neuromuscular junction.
Review Sheet Results
1 Describe the effect of increasing stimulus voltage on isolated skeletal muscle. Specifically
what happened to