PHYSIOLOGY
MUSCLE STRUCTURE FUNCTION
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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the action potential reaches the neuromuscular junction
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ATP binds to sarcoplasmic reticulum
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Acetylcholine enters the synaptic cleft
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Action potential travels along T tubules
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Detailed explanation-1: -As T-tubules bring the sarcolemma very close to the sarcoplasmic reticulum at all regions throughout the cell, calcium can then be released from the sarcoplasmic reticulum across the whole cell at the same time. This synchronisation of calcium release allows muscle cells to contract more forcefully.
Detailed explanation-2: -Depolarization of the sarcolemma (muscle membrane) caused by nerve stimulation causes calcium ions to be released from the sarcoplasmic reticulum.
Detailed explanation-3: -The local membrane of the fiber will depolarize as positively charged sodium ions (Na+) enter, triggering an action potential that spreads to the rest of the membrane will depolarize, including the T-tubules. This triggers the release of calcium ions (Ca++) from storage in the sarcoplasmic reticulum (SR).