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24 Cards in this Set
- Front
- Back
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nerve signal arrives at synaptic knob, causing calcium channels to open & Ca2+ to enter
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excitation
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Ca2+ trigger exocytosis of synaptic vesicles which release ACh into synaptic cleft
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excitation
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ACh binds to receptors on motor end plate, allowing Na+ to enter muscle fiber & K+ to leave muscle fiber
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excitation
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movement of ions across the sarcolemma creates a muscle action potential
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excitation
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muscle action potential spreads throughthe T-tubules into the sarcoplasm
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excitation-contraction coupling
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calcium release channels into sarcoplasmic reticulum and Ca2+ diffuse into sarcoplasm
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excitation-contraction coupling
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calcium ions bind to troponin molecules on thin filaments causing them to change shape
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excitation-contraction coupling
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troponin-tropomyosin complex shifts to a new position exposing myosin binding sites on actin filament so cross bridges can form
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excitation-contraction coupling
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the sliding filament mechanism
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contraction
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thin actin filaments slide inward past thick myosin filaments causing sarcomere to shorten
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contraction
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ATP attaches to ATP binding site on myosin head
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contraction
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ATP is split my myosin ATPase to energize myosin head
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contraction
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cross bridge formed by myosin head attaching to actin
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contraction
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power stroke
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contraction
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myosin head shrivels towar center of sarcomere drawing thin filament past thick filament
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contraction
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2nd ATP attaches to ATP binding site on myosin head, allowing it to detatch from actin filament
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contraction
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myosin head forms new cross bridge further along thin filament to produce another power stroke
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contraction
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repeated over & over to shorten sarcomere as long as ATP and calcium are present
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contraction
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when nerve signals no longer arrive at NMJ, synaptic know stops releasing ACh so nerve signals aren't transferred to motor end plate and calcium channels close
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relaxation
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ACh broken into fragments by acetylcholinesterase
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relaxation
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CA2+ are actively transported out of sarcoplasm & back into scarcoplasmic reticulum where they bind to calsequestrin
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relaxation
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troponin-tropomyosin complex moves back into position to block myosin binding sites on actin
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relaxation
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riger mortis
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relaxation
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CA+ leaks into sarcoplasm & bind to troponin to initiate cross bridge formation
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relaxation
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