1. Acetylcholine is released at    neuromuscular junction 2. AP is propagated along    membrane & down T-tubule 3. Ca released from SR via a     voltage gated Ca channel 4. Ca binds to Troponin-C -     conformation changes     favor tropomyosin opening     actin myosin binding sites. 5. myosin cross-bridges    attach-detach from     actins... pulls filament     toward M-line. 6. Ca is removed by Ca-pump        (uptake by SR) 7. tropomyosin blocks actin    sites and muscle relaxes.