ANA300Y1 Lecture Notes - Lecture 12: Endoplasmic Reticulum, Extracellular Fluid, Myocyte
Document Summary
With change vm of sarcolemma (which occurs with neurotransmission), & t-tubules ,triggers. Increased [ca+2] initiates contraction: change in molecular shape of troponin & mvt. When action potentials cease running down the motor neurons no more acetylcholine release. Any remaining is degraded by acetylcholinesterase without it binding to receptors on postsynaptic membrane thus no more action potential go back to rest for muscle membrane. Ca+2 channels on sarcoplasmic reticulum will close then with channels closed, there are those. Ca+2 pumps cell works hard to sequester ca+2, got ca+2 pumps in cell membrane pumping. Ca+2 into the interstitial fluid ca+2 pumps in membrane of sr pumping ca+2 into the sr. Always working in the background when those ca+2 close on sr, then they will sequester the. Ca+2 again and intercellular ca+2 levels go back to normal and conformational changes in tropomyosin and troponin will get active site covered contraction ends.
