LAB ONE: Skeletal Muscle Physiology
Your assignment is to answer the following questions after completing the lab. Submit your assignment to the Week 1 Dropbox by no later than Sunday, end of week 1, 11:59 P.M. (MT).
1. Define tetanus (6 points)
• Tetanus is a continuous contraction of muscle. In complete tetanus, higher stimulation frequency eliminates the relaxation phase. Incomplete tetanus occurs when the muscle is at almost peak tension during rapid cycles between contraction and relaxation.
• It’s also a disease where sustained and powerful contractions of skeletal muscles are stimulated by the action of a bacterial toxin.
2. Define fatigue (6 points)
• When active skeletal muscle can no longer continue to perform at the required level of activity.
3. Define isometric contractions (6 points)
• A contraction where the muscle doesn’t shorten, but its internal tension increases.
4. Define isotonic contractions (6 points)
• A contraction in which muscle tension remains constant at a given joint angle and load and the muscle shortens.
5. What could be a chemical cause of fatigue? (6 points)
• A decline in pH within the muscle, decreasing calcium ion binding to troponin and altering enzyme activities.
6. What is the key variable in an isometric contraction? (6 points)
• Muscle length; it doesn’t change in isometric contraction and it does in isotonic contractions.
7. Define the term maximal stimulus. (6 points)
• The stimulus where going beyond will not further increase in force.
8. What has happened in the muscle when maximal stimulus is achieved? (6 points)
• All the individual nerve fibers have been stimulated and responding all or none.
9. What is the difference between stimulus intensity and stimulus frequency? (6 points)
• Frequency refers to how often stimulus is applied where intensity increases the force of a stimulus
10. At the threshold stimulus, sodium ions start to move into the cell or out of cell to...