Place in the right sequence of events resulting in excitation-contraction coupling. !! !!! The neurotransmitter travels

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Place In The Right Sequence Of Events Resulting In Excitation Contraction Coupling The Neurotransmitter Travels 1 (240.47 KiB) Viewed 138 times

Place in the right sequence of events resulting in excitation-contraction coupling. !! !!! The neurotransmitter travels across the synaptic cleft where it binds to its receptor causing depolarization of the muscle cell membrane (sarcolemma) and sends a(n) action potential along the sarcolemma and the t-tubules (extensions of sarcolemma that help send the signal deep into the muscle fibre). For force generation, the cross-bridge must move into a 'power stroke' which requires the hydrolysis of ATP. As the depolarization reaches the sarcoplasmic reticulum, it causes opening of voltage-gated channels allowing the release of calcium. It then moves tropomyosin out of the myosin binding site on the actin filament. After completing the power stroke, the myosin head must detach from actin - this requires a new ATP to bind to myosin, allowing the detachment. The myosin head will re-attach to actin provided ATP is still present which keeps tropomyosin out of the myosin binding site on actin. To initiate skeletal muscle contraction, a(n) action potential travels from the central nervous system down a motor neuron where it reaches an axon terminal. A myosin head is able to bind to actin, which is called a cross-bridge. Calcium is released inside the axon terminal which triggers the release of acetylcholine by exocytosis into the synaptic cleft. Calcium then binds to troponin, a protein located actin (thin filament).