Sequence the events that take place when a motor neuron\'s action potential trig
ID: 146177 • Letter: S
Question
Sequence the events that take place when a motor neuron's action potential triggers a muscle contraction. The motor neuron action potential arrives at the neuromuscular junction Sarcomeres within the muscle fibers contract. transverse (T) tubules carry the action potential throughout the muscle fiber. en the tropomyosin shifts position as calcium ions bind to troponin, actin binding sites are exposed Acetylcholine arrives at the muscle fibers plasma membrane, which causes the membrane to depolarize. The sarcoplasmic reticulum becomes more permeable in response to the action potential, causing a release of calcium ions. Myosin cross-bridges attach to actin fibers.Explanation / Answer
The motor neuron action potential arrives at the neuromuscular junction.
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Acetylcholine arrives at the muscle fiber's plasma membrane, which causes the membrane to depolarize.
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The transverse (T) tubules carry the action potential throughout the muscle fiber.
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The sarcoplasmic reticulum becomes more permeable in response to the action potential, causing a release of Calcium ions.
(Action potential in T tubules causes this release of calcium ions
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When the tropomyosin shifts position as calcium ions bind to troponin, actin binding sites are exposed.
(The tropomyosin was blocking the actin binding sites)
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Myosin cross-bridges attach to actin fibers.
(ATP bound to myosin gets hydrolysed. The myosin cross bridges produce sliding movement of thin filaments against thick filaments).
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Sarcomeres within the muscle fibers contract.
(The contraction continues until calcium is removed from troponin and transported back into the sarcoplasmic reticulum. Removal of calcium causes tropomyosin back to its position blocking actin)
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