Skeletal Muscle Physiology
LAB TIME/DATE:9pm.. 4.8.11
1. Name each phase of a typical muscle twitch, and, on the following line, describe what is happening in each phase. a. Latent-stage from rest to muscle tension begins
b. Contraction-At this stage the muscle reaches its peak in contraction
c. Relaxation- muscle is shortened, returns to zero and back initial length.
2. In Activity 2, how long was the latent period? ___2.2_______ msec Describe the chemical changes that are occurring during this period. Calicum levels are low since muscle contaction is not at its peak. Preparing for the the contraction Ca begin the process of sending Acetychlorine binding to the Sacroplasma
The Graded Muscle Response to Increased Stimulus Intensity
3. From Activity 3, describe the effect of increasing the voltage. What happened to the force generated and why did this change occur? Higher voltage results in higher force and a higher contractile force
4. How does this change occur in vivo?Tthe more stimulus of muscle require more work on the cells which requires more Ca+2 to facilitate this stimulus increase.
5. In Activity 4, you looked at the effect of stimulating the muscle multiple times in a short period with complete relaxation between the stimuli. Describe the force of contraction with each subsequent stimulus. The force of contraction is higher with each subsequent stimulus.
6. Describe the chemical changes that are thought to correlate to this change in vivo. this requires more Ca+2 in the sacroplasm and more activity on the thin filament for cross-bridge attachments.
7. In Activity 5, what was the effect of increasing the frequency of stimulation? Increase frequency of stimuli result in increased muscle tension.
8. Compare and contrast wave summation with recruitment (multiple motor unit summation). How are they similar? How was each achieved in the simulation? They are...
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