Question

Flag question "All or none" applies to Select one: a. individual muscle fibers O b. muscle bundles Clear my choice

Answer 1

1. All or none applies to individual muscle fibers in which the strength with which they respond to stimulus is independent of strength of stimulus.

2. Slow twitch muscle fibers which are efficient for longer periods of time are found in postural muscles.

3. Skeletal muscle relaxation occurs when Ca+2 transported to SR and when this happens actin and myosin move back to their unbound phase.

7. True. The length remains same and thin filaments slide over one another during contraction.

8. True. The length of A bands do not change during contraction.

9. During contraction the width of sarcomere decreases as the A band remains the same but the I band decreases.

10. Fast twitch muscle have enhanced glycogen deposition  and used in high intensity short duration activities as they fatigue faster.

11. Slow twitch muscle have higher concentration of mitochondria and myoglobin and better vascularization.

12. Sustained muscle contraction describes tetanus.  

13. Power stroke is release of cross bridge returning myosin head to original position.