BIOL 382 Lecture 23: Anatomy 1 - lecture 23
Document Summary
End of axon innervates muscles or glands. Ligand can bring depolarization of postsynaptic membrane. Calcium ions kept within lateral sacs - t tubules. When impulse goes down t-tubule -- destroys lateral sacs. Allows ca+ ions to leave and flood area. 1) when impulse travels down t tubules. 2) when released in high concentrations, attaches to t-t complex and pushes it aside. Exposes myosin crossbridge binding site on actin myofilament. Crossbridges attach and leads to am1 complex (powerstroke) uncouples actins and detachment ---- am2 complex. 2) action potential goes down terminal branches. 4) ach diffuses across synaptic cleft and attach to receptors on mep, depolarizes mep. 8) depolarize lateral sacs and release sequestered ca+ ions into lateral sacs. Time b/w ap generation on motor neuron of sarcolemma and beginning of actual mechanical activities if muscle cell shortening as result of sliding filament. The time duration b/w application of stimulus and response.
