What is the correct sequence for the following events of muscle contraction?
1)Calcium ions are released from the sarcoplasmic reticulum.
2)Power stroke pulls actin toward center of A band.
3)Impulse travels into the T-tubules.
4)Energized myosin heads attach to actin.
5)Calcium reacts with troponin and exposes binding sites on actin.
A) 1, 3, 5, 2, 4
B) 3, 1, 5, 4, 2
C) 1, 5, 4, 2, 3
D) 3, 5, 4, 2, 1
E) 2, 4, 5, 3, 1

Question

Quizplus · Accepted Answer

The correct sequence for muscle contraction is: 
1) Impulse travels into the T-tubules to stimulate the release of calcium ions from the sarcoplasmic reticulum.
2) Calcium ions react with troponin, exposing the binding sites on actin.
3) Energized myosin heads attach to the binding sites on actin.
4) Power stroke pulls actin toward the center of the A band, shortening the sarcomere.
5) The muscle relaxes when calcium ions are pumped back into the sarcoplasmic reticulum.

Therefore, the correct sequence is: 3, 1, 5, 4, 2 which corresponds to choice B.

What Is the Correct Sequence for the Following Events of Muscle