Title | Physio Ex Exercise 2 Activity 1 |
---|---|
Author | Kaley Rose |
Course | Anatomy And Physiology |
Institution | Community College of Rhode Island |
Pages | 6 |
File Size | 368 KB |
File Type | |
Total Downloads | 92 |
Total Views | 142 |
Pearson PhysioEx Lab ...
PhysioEx Lab Report Exercise 2: Skeletal Muscle Physiology Activity 1: The Muscle Twitch and the Latent Period Name: Kaley Faucher Date: 15 September 2020 Session ID: session-844701bb-5a94-7dfd-3390-346ae72b409e
Pre-lab Quiz Results You scored 100% by answering 5 out of 5 questions correctly. 1 Skeletal muscles are connected to bones by You correctly answered: tendons. 2 Skeletal muscles are composed of hundreds to thousands of individual cells called You correctly answered: fibers. 3 The term motor unit refers to You correctly answered: one motor neuron and all of the skeletal muscle fibers it innervates. 4 The motor neuron and muscle fiber intersect at what is called You correctly answered: the neuromuscular junction. 5 A twitch is You correctly answered: one contractile response to a single action potential.
Experiment Results Predict Question 1 Predict Question: Will changes to the stimulus voltage alter the duration of the latent period? Your answer: Yes, changing the stimulus voltage will change the latent period duration proportionately. Stop & Think Questions 1 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: The latent period.
2 What occurs during the latent period of these isometric contractions? You correctly answered: All the steps of excitation-contraction coupling occur. Experiment Data Voltage (v)
Length (mm)
Active Force Passive Force
Total Force
Latent Period (msec)
0
75
0
0
0
----
3
75
1.04
0
1.04
----
4
75
1.32
0
1.32
4.00
2
75
0.66
0
0.66
3.20
4
75
1.32
0
1.32
3.20
6
75
1.65
0
1.65
3.20
8
75
1.81
0
1.81
3.20
10
75
1.82
0
1.82
3.20
Voltage = 0 V
Voltage = 3 V
Voltage = 4 V
Voltage = 2 V
Voltage = 4 V
Voltage = 6 V
Voltage = 8 V
Voltage = 10 V
Post-lab Quiz Results You scored 100% by answering 6 out of 6 questions correctly. 1 An action potential in a motor neuron triggers the release of which neurotransmitter?
You correctly answered: acetylcholine. 2 The term skeletal muscle fiber refers to You correctly answered: 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: an EPP (end-plate potential). 4 Which of the following is not a phase of a skeletal muscle twitch? You correctly answered: hyperpolarization phase. 5 A skeletal muscle twitch is You correctly answered: one contractile response to a single action potential. 6 Which of the following correctly matches the twitch phase with its definition? You correctly answered: the contraction phase: the time between the end of the latent period and peak muscle tension.
Review Sheet Results 1 Define the terms skeletal muscle fiber, motor unit, skeletal muscle twitch, electrical stimulus, and latent period. Your answer: Skeletal muscle fiber: the mechanical response to a single action potential motor unit: one motor neuron and all the muscle fibers skeletal muscle twist:mechanical response to a single action potential. electrical stimulus: stimulus that activates the end plate potential latent period: the time period between a action in a muscle cell and when the muscle starts to contract. 2 What is the role of acetylcholine in a skeletal muscle contraction? Your answer: Acetylcholine is released in the end plate potential. It binds receptors to the motor and initiates the change in ion permeability. 3 Describe the process of excitation-contraction coupling in skeletal muscle fibers. Your answer:
Converts an electrical stimulus to a mechanical response. It is the link between action potential and the start of muscle contraction. 4 Describe the three phases of a skeletal muscle twitch. Your answer: latent period: the time between action potential and the start of muscle contraction contraction phase: starts at the muscle contraction (end of latent period) and ends when the muscle tension peaks relaxation phase: the time elapsed between muscle tension peak and the end of the muscle contraction. 5 Does the duration of the latent period change with different stimulus voltages? How well did the results compare with your prediction? Your answer: Stimulus voltage increases while the active force of muscle increases. The latent period is the time between the potential and the muscle contraction, and I found that the latent period changed (increased) in time when the stimulus voltage was increased. 6 At the threshold stimulus, do sodium ions start to move into or out of the cell to bring about the membrane depolarization? Your answer: At the threshold stimulus, sodium ions start to move into the cell....