MUSCLE
SKELETAL MUSCLE
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Ca++
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AChE
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Na+
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ATP
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Detailed explanation-1: -Upon depolarization, an action potential travels down the axon, causing voltage-gated calcium channels to open, resulting in an influx of calcium ions into the nerve terminal. This causes the vesicles to migrate towards the nerve terminal membrane and fuse with the active zones.
Detailed explanation-2: -The acetylcholine binds to the nicotinic receptors concentrated on the motor end plate, a specialized area of the muscle fibre’s post-synaptic membrane. This binding causes the nicotinic receptor channels to open and let sodium ions enter the muscle fibre.
Detailed explanation-3: -The muscle fiber action potential, which sweeps along the sarcolemma as a wave, is “coupled” to the actual contraction through the release of calcium ions (Ca++) from the SR.
Detailed explanation-4: -Binding of the receptors cause sodium ions (Na+) to enter the muscle cell and potassium ions (K+) to exit the cell; this process causes a local depolarization of the muscle cell = end plate potential (EPP).