BIOL-2220 Lecture Notes - Lecture 3: Myosin Light-Chain Kinase, Endoplasmic Reticulum, Neuromuscular Junction
23 Jan 2018
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Document Summary
Organized into sheets (longitudinal layer: opens up diameter of the blood vessel and circular layer: causes constriction of blood vessels) Cant store ca inside the cell, instead internal folds (caveolie) 10-15 thin myofilaments for each long thick myofilament. Myosin heads found along entire length of thick myofilament. Tropomyosin associated with thin myofilament, but no troponin actin. Sites are always open; myrosin cant bind until its charged. Attach to dense bodies (on sarcolemma of smooth muscle cells), and stretch from one to another. Smooth muscle types: viseral: contracts rhythmically as a unit (ex: stomach) Found in walls of hollow organs: multiunit: each functions separately (ex: erector pilli muscle) Calcium is released by caveoli (more importantly taken in from extracellular space) Calcium binds to calmodulin (calmodulin is a calcium binding protein inside the cell) Activated calmodulin activates myosin light chain kinase (atpase) Relaxation: neurotransmitter stops and ca gets pumped out of cell.
