During muscle contraction, individual That is, the distance between Z bands decr

Question

During muscle contraction, individual That is, the distance between Z bands decreases. Muscle contraction is divided into two phases: shorten their length. Phase 1: muscle cell is stimulated by a -Phase 2: coupling occurs Phase 1 details: AP arrives at causing voltage-gated fuse with plasma membrane channels to open, allowing vesicles containing NT to released into synapse; binds permeability of sarcolemma changes, as on sarcolemma ions flow into the muscle cell and Local AP occurs in ions flow out of the muscle cell occurs Phase 2 details: spreads across entire sarcolemma AP travels along T tubules " releases , which binds to , which removes the blocking action of

Explanation / Answer

During muscle contraction, individual sarcomere shorten their length. That is, the distance between Z bands decreases.

Muscle contraction is divided into two phases:

Phase 1: muscle cell is stimulated by a neurotransmitter

Phase 2: excitation-contraction coupling occurs.

Phase 1 details:

AP arrives at pre-synaptic knob, causing voltage-gaated calcium channels to open, allowing vesicles containing neurotransmitter to fuse with plasma membrane.

Neurotransmitter (acetylcholine) released into synapse, binds to nicotinic cholinergic receptors on sarcolemma.

Membrane permeability of sarcolemma changes, as sodium ions flow into the muscle cell and potassium ions flow out of the muscle cell.

Local positive change inside muscle fibre called end plate potential occurs.

AP occurs in sarcomere or muscle fiber.

Phase 2 details:

Action potential spreads across entire sarcolemma

AP travels along T tubules

Sarcoplasmic reticulum releases calcium, which binds to troponin c-subunit, which removes the blocking action of neurotransmitter.

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