Physiolab 9.0 Exercise 2
NAME Rachel Brockhuis
LAB TIME/DATE _______________________
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. Motor unit- single α-motor neuron and all of the corresponding muscle fibers it innervates; all of these fibers will be of the same type
Skeletal muscle fiber- long and narrow cells that often span the entire length of a muscle
Skeletal muscle twitch- an activation of a muscle by firing a motor neuron
Electrical stimulus- the application of an electric current by means of a prosthesis to stimulate and restore partial function to a muscle disabled by neurologic lesions
Latent period-a seemingly inactive period, as that between exposure to an infection and subsequent illness, or that between the instant of stimulation and the beginning of response.
2. What is the role of acetylcholine in a skeletal muscle contraction? Acetylcholine is the chemical signal the nerve sends to the muscle to cause contraction
3. Describe the process of excitation-contraction coupling in skeletal muscle fibers. ACH is released at the end-plate potential. ACH diffuses into the sarcolemma, attaches to the receptors in the motor end plate and causes a change in the ions permeability that creates graded depolarization of the end-plate potential. Basically, it attaches to the receptors in the motor-end plate and creates the beginning process of triggering muscle contractions.
4. Describe the three phases of a skeletal muscle twitch.
Latent Phase: During this phase there is no muscle contraction. This phase is the period of time prior to muscle contractions. The latent phase, chemical changes in the cells occur in preparation for muscle contractions.
Contraction Phase: Is the period in which the muscle tension is at it's highest. This is the time where the greatest amount of muscle force is generated. It begins at the end of the latent
LAB TIME/DATE _______________________
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. Motor unit- single α-motor neuron and all of the corresponding muscle fibers it innervates; all of these fibers will be of the same type
Skeletal muscle fiber- long and narrow cells that often span the entire length of a muscle
Skeletal muscle twitch- an activation of a muscle by firing a motor neuron
Electrical stimulus- the application of an electric current by means of a prosthesis to stimulate and restore partial function to a muscle disabled by neurologic lesions
Latent period-a seemingly inactive period, as that between exposure to an infection and subsequent illness, or that between the instant of stimulation and the beginning of response.
2. What is the role of acetylcholine in a skeletal muscle contraction? Acetylcholine is the chemical signal the nerve sends to the muscle to cause contraction
3. Describe the process of excitation-contraction coupling in skeletal muscle fibers. ACH is released at the end-plate potential. ACH diffuses into the sarcolemma, attaches to the receptors in the motor end plate and causes a change in the ions permeability that creates graded depolarization of the end-plate potential. Basically, it attaches to the receptors in the motor-end plate and creates the beginning process of triggering muscle contractions.
4. Describe the three phases of a skeletal muscle twitch.
Latent Phase: During this phase there is no muscle contraction. This phase is the period of time prior to muscle contractions. The latent phase, chemical changes in the cells occur in preparation for muscle contractions.
Contraction Phase: Is the period in which the muscle tension is at it's highest. This is the time where the greatest amount of muscle force is generated. It begins at the end of the latent