Question

Which statements are true of summation? 1 pt O A second nerve stimulus occurs before the muscle has had time to relax (1.e., before cell Ca2+ concentration has been restored to resting values). O A second stimulus is delivered while the nerve axon is depolarized. O A second stimulus occurs while the muscle cell membrane is depolarized. More motor units are recruited. Draw the appropriate force/tension response of skeletal muscles in the images below. 4 pts Twitch Summation Incomplete tetanus Complete tetanus Tension (N) 100 200 300 400 100 200 300 400 100 200 300 400 100 200 300 400 → Time (ms) Annotate Start Over

Answer 1

Answer : a second nerve stimuli occurs before the muscle had time to relax (i.e before the calcium concentration has been restored to resting values)

Summation

The summation occurs when the second stimulus triggers the release of more calcium ions, which becomes available for the activation of additional sarcomeres, while the muscle is still contracting from the first stimulus. The summation causes a greater contraction of the unit.

The other options are not relevant answers with respect to the term summation.

Thumbs up would be really helpful. Happy Chegging!