PHYSL212 Lecture Notes - Lecture 27: Smooth Muscle Tissue, Endoplasmic Reticulum, Fundamental Interaction
4 Dec 2016
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Physl 212 - lecture #27 - smooth muscle cell organization and contraction. Smooth muscle cell (smc) organization: unitary: like cardiac = one motor unit innervates many. Efflux of calcium from the sarcoplasmic reticulum. Know that a g protein is then activated, and that it [ip3: don"t need to know about epinephrine, norepinephrine, etc. Smooth muscle contraction: force production in all muscle types depends on the same fundamental interaction between actin-myosin, force regulation varies substantively between smooth and striated muscle. In smooth muscle, there is no troponin complex. Which means there is no calcium binding sites. Calcium activates calmodulin-dependent protein kinases [myosin light chain. Kinase (mlck): ca2+ must bind with calmodulin (protein) to activate it, calmodulin binds with mlck and increases the activity of the kinase, phosphorylating the regulatory light chain creates a crossbridge. Atpase activity of the myosin head. Essential for crossbridge cycling in smooth muscle cells. This increase must happen for get the cycling.
