Which of the following places the events in the correct orde

Which of the following places the events in the correct order they occur during excitation and contraction?

Solution

(A) Action potential travels down T-tubule --> Calcium released into sarcoplasmic reticulum --> Troponin binds to calcium --> Myosin interacts with actin -->Active sites of actin are exposed

Sequence of events in excitation-contraction coupling

1

As the first event, the action potential is seen getting propagated along sarcolemma and down t tubules

2

Now this action potential will trigger the release of calcium from terminal cisternae of sarcoplasmic reticulum

3

Now the released calcium will go and bind to troponin c, the troponin changes shape, and then removes the blocking action of tropomyosin, which causes the exposure of the actin active sites.

5

This will result in contraction

6

When the action potential ends, the calcium will be removed by re-uptake into the sarcoplasmic reticulum.

7

Now again the tropomyosin blockage will be restored, the contraction phase will end and the muscle fiber relaxes.