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PEX 02 01
Exercise 2: Skeletal Muscle Physiology: Activity 1: The Muscle Twitch and the Latent Period Lab Report
Pre-lab Quiz Results
You have not completed the Pre-lab Quiz.

03/21/15

page 1

Experiment Results
Predict Question:
Predict Question: Will changes to the stimulus voltage alter the duration of the latent period?
Your answer : b. No, changing the stimulus voltage will not change the latent period duration.
Stop & Think Questions:
What is the period of time that elapses between the generation of an action potential and the start of muscle tension development in a muscle fiber?
You correctly answered: c. the latent period
What occurs during the latent period of these isometric contractions?
You correctly answered: b. All the steps of excitation-contraction coupling occur.
Experiment Data:
Voltage
0.0
3.0
4.0
6.0
8.0
10.0

Length
75
75
75
75
75
75

Active Force
0.00
1.04
1.32
1.65
1.81
1.82

Passive Force
0.00
0.00
0.00
0.00
0.00
0.00

03/21/15

page 2

Total Force
0.00
1.04
1.32
1.65
1.81
1.82

Latent Period
----2.80
2.40
2.40
2.40

03/21/15

page 3

03/21/15

page 4

Post-lab Quiz Results
You scored 100% by answering 7 out of 7 questions correctly.
1. An action potential in a motor neuron triggers the release of which neurotransmitter?
You correctly answered: b. acetylcholine
2. The term skeletal muscle fiber refers to
You correctly answered: a. an individual skeletal muscle cell.
3. The graded depolarization in the skeletal muscle fiber that is elicited in response to one action potential from the motor neuron is called
You correctly answered: c. an EPP (end-plate potential).
4. Which of the following is not a phase of a skeletal muscle twitch?
You correctly answered: b. hyperpolarization phase
5. A skeletal muscle twitch is
You correctly answered: a. one contractile response to a single action potential.
6. Which of the following correctly matches the twitch phase with its definition?
You correctly answered: d. the contraction phase: the time between the end

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