anatomy
NAME __Molly Manning__
LAB TIME/DATE ___10/24/13__
Exercise 2
Skeletal Muscle Physiology
The Muscle Twitch and the Latent Period
1. Define the terms skeletal muscle fiber, motor unit, skeletal muscle twitch, electrical stimulus, and latent period. Skeletal muscle fiber-fibers attached to the skeleton that produce muscle tension. Motor unit-consists of the motor neuron and all of the muscle fibers. Skeletal muscle twitch-mechanical response to a single action potential. Electrical stimulus-muscle contractions. Latent period- during a contraction there is a rise in muscle tension.
2. What is the role of acetylcholine in a skeletal muscle contraction? -Trigger action potential.
3. Describe the process of excitation-contraction coupling in skeletal muscle fibers. –The motor end plate produces potential and results in contraction of a single cell.
4. Describe the three phases of a skeletal muscle twitch. 1) Latent period-time lapse between action potential and muscle contraction. 2) Contraction phase-starts at end of latent period and ends when muscle tension peaks. 3) Relaxation phase-starts at peak of 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? – Yes, the results varied in different time amounts.
6. At the threshold stimulus, do sodium ions start to move into or out of the cell to bring about the membrane depolarization? –They start to move out of the cell.
A C T I V I T Y 2 The Effect of Stimulus Voltage on Skeletal Muscle Contraction
1. Describe the effect of increasing stimulus voltage on isolated skeletal muscle. Specifically, what happened to the muscle force generated with stronger electrical stimulations and why did this change occur? How well did the results compare with your prediction?
-Contraction occurred with increasing voltage in skeletal muscle. These results matched my
LAB TIME/DATE ___10/24/13__
Exercise 2
Skeletal Muscle Physiology
The Muscle Twitch and the Latent Period
1. Define the terms skeletal muscle fiber, motor unit, skeletal muscle twitch, electrical stimulus, and latent period. Skeletal muscle fiber-fibers attached to the skeleton that produce muscle tension. Motor unit-consists of the motor neuron and all of the muscle fibers. Skeletal muscle twitch-mechanical response to a single action potential. Electrical stimulus-muscle contractions. Latent period- during a contraction there is a rise in muscle tension.
2. What is the role of acetylcholine in a skeletal muscle contraction? -Trigger action potential.
3. Describe the process of excitation-contraction coupling in skeletal muscle fibers. –The motor end plate produces potential and results in contraction of a single cell.
4. Describe the three phases of a skeletal muscle twitch. 1) Latent period-time lapse between action potential and muscle contraction. 2) Contraction phase-starts at end of latent period and ends when muscle tension peaks. 3) Relaxation phase-starts at peak of 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? – Yes, the results varied in different time amounts.
6. At the threshold stimulus, do sodium ions start to move into or out of the cell to bring about the membrane depolarization? –They start to move out of the cell.
A C T I V I T Y 2 The Effect of Stimulus Voltage on Skeletal Muscle Contraction
1. Describe the effect of increasing stimulus voltage on isolated skeletal muscle. Specifically, what happened to the muscle force generated with stronger electrical stimulations and why did this change occur? How well did the results compare with your prediction?
-Contraction occurred with increasing voltage in skeletal muscle. These results matched my