PHYSIOLOGY
MUSCLE CONTRACTION
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Capacity
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Threshold
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Ionization
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Critical
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Detailed explanation-1: -Propagation of an action potential along the sarcolemma is the excitation portion of excitation-contraction coupling. Recall that this excitation actually triggers the release of calcium ions (Ca++) from its storage in the cell’s SR.
Detailed explanation-2: -Through the DHPR, the action potential in the sarcolemma triggers the opening of RyR, allowing Ca++ to diffuse out of the SR and into the sarcoplasm. It is the arrival of Ca++ in the sarcoplasm that allows for the binding of actin and myosin and thus initiates contraction and shortening of sarcomeres.
Detailed explanation-3: -Excitation–Contraction Coupling. Excitation–contraction coupling is the link (transduction) between the action potential generated in the sarcolemma and the start of a muscle contraction.