객관식
Which of the following steps of the crossbridge cycle occurs immediately before the power stroke?
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9. Muscle Tissue
Steps of Muscle Contraction
객관식
Which of the following correctly lists the steps of muscle fiber contraction in the proper sequence?
A
Acetylcholine is released, action potential arrives at the neuromuscular junction, myosin binds to actin, calcium ions are released from the sarcoplasmic reticulum, muscle fiber contracts.
B
Myosin binds to actin, acetylcholine is released, action potential arrives at the neuromuscular junction, calcium ions are released from the sarcoplasmic reticulum, muscle fiber contracts.
C
Action potential arrives at the neuromuscular junction, acetylcholine is released, calcium ions are released from the sarcoplasmic reticulum, myosin binds to actin, muscle fiber contracts.
D
Calcium ions are released from the sarcoplasmic reticulum, action potential arrives at the neuromuscular junction, acetylcholine is released, myosin binds to actin, muscle fiber contracts.
검증된 단계별 안내1
Step 1: Understand the sequence of events in muscle fiber contraction. Muscle contraction begins with an action potential traveling down a motor neuron to the neuromuscular junction.
Step 2: At the neuromuscular junction, the arrival of the action potential triggers the release of acetylcholine, a neurotransmitter, into the synaptic cleft.
Step 3: Acetylcholine binds to receptors on the muscle fiber's sarcolemma, leading to depolarization and the generation of an action potential in the muscle fiber.
Step 4: The action potential travels along the sarcolemma and down the T-tubules, causing the sarcoplasmic reticulum to release calcium ions into the cytoplasm of the muscle fiber.
Step 5: Calcium ions bind to troponin, causing a conformational change that moves tropomyosin away from the binding sites on actin. This allows myosin heads to bind to actin, initiating the cross-bridge cycle and muscle contraction.
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