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Filaments PowerPoint Presentation

Filaments

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Filaments

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Presentation Transcript

  1. Filaments

  2. Resting state

  3. Electrical impulse (Action Potential) reaches axon terminal

  4. Impulse opens Calcium Channels, rapid influx of Calcium into terminal

  5. Vesicles with acetylcholine (Ach)bind to cell membrane & releases Ach into synaptic cleft

  6. Vesicles with acetylcholine (Ach) bind to cell membrane & releases Ach into synaptic cleft Ach

  7. Ach binds to receptors on motor end plate

  8. Ach receptors opens Na+ channels, causes an influx of sodium into muscle

  9. Sodium influx triggers a muscle impulse (electrical signal) in all directions of muscle fiber.

  10. Electrical impulse travels across Sarcolemma, down t-tubules, and across cisternae Sarcolemma

  11. Electrical impulse travels across Sarcolemma, down t-tubules, and across cisternae

  12. Sarcoplasmic Reticulum releases Calcium into Sarcoplasm Sarcoplasmic Reticulum

  13. Ca2+ (Calcium) Triggers muscle contraction by binding to troponin

  14. Tropomyosin moves and exposes actin filaments to cross bridges

  15. Cross bridges bind to actin & pulls actin forward (ADP is released from cross bridge)

  16. Cross bridges bind to actin & pulls actin forward (ADP is released from cross bridge)

  17. Videos • Breakdown of ATP • Synapse Transmission • Action Potential Across Sarcolemma • Shortening Sarcomere

  18. Relaxation • Calcium pumps return Calcium to Sarcoplasmic reticulum • Acetylcholinesterase clears ACh from synaptic cleft • ATP binds to cross bridge & myosin is released from actin * • ATPase converts ATP to ADP using energy to cock cross bridge* • Tropomyosin cover actin filaments • * Note: ATP is required for both muscle contraction & relaxation

  19. Myofibrils • Actin Filaments “thin” • Anchored to z-lines (filament proteins) • I bands (light color) = actin + z-lines • Myosin Filaments “thick” • A-band (dark color) = Myosin filaments + overlapping Actin filaments • H-zone (slightly lighter) = Myosin filaments between overlapping actin • Sarcomere • Area between 2 z-lines • Functional unit of skeletal muscle • During contraction adjacent z-lines approach each other