Physio EX-02-01 PDF

Preview

Summary

Moore...

Description

Name: Lily Rosenblum Exercise 2: Skeletal Muscle Physiology: Activity 1: The Muscle Twitch and the Latent Period Lab Report 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: b. tendons. 2. Skeletal muscles are composed of hundreds to thousands of individual cells called You correctly answered: c. fibers. 3. The term motor unit refers to You correctly answered: c. 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: d. the neuromuscular junction. 5. A twitch is You correctly answered: a. one contractile response to a single action potential.

10/07/18

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 4.0 6.0

Length 75 75 75 75 75

Active Force 0.0 1.04 1.32 1.32 1.65

8.0 10.0

75 75

1.81 1.82

Passive Force 0.0 0.0 0.0 0.0 0.0 0.0 0.0

10/07/18

page 2

Total Force 0.0 1.04 1.32 1.32 1.65 1.81 1.82

Latent Period ---------3.20 2.80 3.20 2.80

10/07/18

page 3

10/07/18

page 4

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: 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 of the latent period and peak muscle tension

10/07/18

page 5

Review Sheet Results 1. Define the terms skeletal muscle fiber, motor unit, skeletal muscle twitch, electrical stimulus, and latent period. Your answer: A skeletal muscle fiber is where a cell from a single muscle made up of skeletal muscle. A motor neuron with the muscle fiber it innervates is reffered to as a motor unit. The skeletal muscle twitch is response to a single action potential. An electrical stimulus maks the muscle contract. The period between stimulating and start of contraction is called the Latent Period. 2. What is the role of acetylcholine in a skeletal muscle contraction? Your answer: Acetylcholine is primarily responsible for when it diffuses through the muscle fiber's membrane and binds to receptors in the motor endplate. It then results in making the electric potential. 3. Describe the process of excitation-contraction coupling in skeletal muscle fibers. Your answer: The neutromusclular juction progresses to the end plate potential (EPP) and the EPP triggers a process resulting in the contraction of a muscle cell. 4. Describe the three phases of a skeletal muscle twitch. Your answer: There are three phases: Latent Period, Contraction, and Relaxation. The latent period is between the generation of an acttion potential and the start of a contraction in a muscle. The contraction period is between the end of the latent period and ends when the muscle tension peaks. The relaxation period is the last phase and is the period from peak tension until 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: During the whole experiment, the latent period remained the same as I predicted. 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: The sodium ions will move into the cell during the threshold stimulus to make the membrane depolarize overtime.

10/07/18

page 6...