Biology Forums - Study Force

Pre-lab Quiz Results

1. Skeletal muscle fibers are innervated (stimulated) by
c. motor neurons.
2. A single action potential propagating down a motor axon results in
d. a single action potential and a single contractile event in the muscle fibers it innervates.
3. In resting skeletal muscle, calcium is stored in
c. the sarcoplasmic reticulum.
4. During the latent period for an isometric contraction
c. the cellular events involved in excitation-contraction coupling occur.

Stop & Think Questions:

What do you see in the active force display when the stimulus voltage is set to 0.0, and why does this observation make sense?
a. 0.00 g; there was no activation of skeletal muscle fibers by this stimulus.
What is the lowest stimulus voltage that induces active force in the skeletal muscle?
b. threshold voltage

Post Lab Quiz:

1. Motor unit recruitment refers to
a. an increase in the number of active muscle fibers to increase the force developed in a muscle.
2. Active tension (or force) in a skeletal muscle fiber results from
a. activation of cross bridge cycling via increased intracellular calcium levels.
3. The ________ is the minimal stimulus needed to cause a depolarization of the muscle plasma membrane (sarcolemma).
d. threshold voltage
4. By definition, the ________ is the amount of stimulus required to successfully recruit all the muscle fibers into developing active force.
c. maximal voltage
5. Why was a maximal voltage observed in this experiment?
b. At the maximal voltage, all the muscle fibers contained in this muscle are depolarized and they
all develop active force (that is, they were all successfully recruited).
6. A sufficiently strong electrical stimulus applied to an isolated, mounted skeletal muscle induces the development of muscle force, or muscle tension. Which of the following statements concerning this observation is true?
c. The electrical stimulus mimics acetylcholine release at a neuromuscular junction

Thanks for sharing...

We appreciate your post :) It helps a lot!