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22 Cards in this Set
- Front
- Back
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Smooth muscle properties
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short, single nucleus, non striated, NO myofibrils, NO sarcomeres, have actin and myosin, electrically coupled by gap jxns, involuntary, ANS control and local control
layers in tubes and organs |
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smooth muscle capillaries contract the tunica...
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media; capillaries and some smaller venues do not have SMCs
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SMC contraction
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AP--> MB depol--> VG Ca2+ channels--> increase Ca2+ in ICF--> Ca2+ binds calmodulin--> activates MLCK--> P-Myosin + actin--> contract
(MLC phosphatase--> myosin deP--> relaxation) |
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Myosin light chain phosphorylation
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allows myosin-actin binding and contraction in SMCs
myosin heavy chain = contractile myosin light chain = regulatory |
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Sources of Ca2+ in SMC
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L type VG, ligand gated ca2+ channels, SR has RyR Ca2+ gated, SERCA pumps (puts ca2_ away), NCX (na+/ca2+ exchanger), ca2+ atpase pumps (pumps ca2+ out)
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explain how contraction and tension development can occur when intracellular ca2+ levels decrease
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b/c of phosphorylation
SMC unique cause it can stay contracted even after put ca2+ away because of the phosphorylation |
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can change contractile state of SMC at any given ca2+ level
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SMC contracts b/c of other ca2+ independent signaling pathways can affect MLCK and MLCP
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mechanism that endothelial derived hyperpolarizing factors (H2O2) causes VSMC relaxation
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H2O2--> K+ hyperpol--> relax
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amlodipine
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DHPYR ca2+ antagonist--I influx of ca2+ (binds more SMC vs. cardiac cells)--> peripheral arterial vasodilator--> reduces peripheral vascular resistance and decrease BP
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Nitroglycerine
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dilate veins--> returns less blood to the heart--> heart works less
targets mostly the veins NO--> guanylate cyclase--> increase cGMP in SMC--> dephospho rylation of MLC--> regulate contractile state in SMC--> vasodilation |
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nitroglycerine mech
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nitroglycerine--> NO--> guanylate cyclase--> cGMP--> PKG--> MLCP--> myosin dephosphorylates--> relaxation
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Tadalafil (--------> creates more cGMP)
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NO from parasympathetic nerves and endothelial cells--> cGMP--> SMC relaxation--> increased blood flow into corpus cavernoum
tadalafil + sex stimulation--I PDE5--> enhances erectile fan by increasing cGMP |
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nitroglycerine mech
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nitroglycerine--> NO--> guanylate cyclase--> cGMP--> PKG--> MLCP--> myosin dephosphorylates--> relaxation
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PDE5
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changes cGMP--> GMP
need sexual activity b/c need NO to be active gotta turn on NO to have any effect on GC to make cGMP, which then PDE5 can work on to create GMP |
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Tadalafil (--------> creates more cGMP)
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NO from parasympathetic nerves and endothelial cells--> cGMP--> SMC relaxation--> increased blood flow into corpus cavernoum
tadalafil + sex stimulation--I PDE5--> enhances erectile fan by increasing cGMP |
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can't give NO and tadalafil together
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b/c target same pathways so will extremely vasodilator
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PDE5
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changes cGMP--> GMP
need sexual activity b/c need NO to be active gotta turn on NO to have any effect on GC to make cGMP, which then PDE5 can work on to create GMP |
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epinephrine
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SKM blood flow increases, skin blood flow decreases, airways in lungs increase in diameter
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can't give NO and tadalafil together
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b/c target same pathways so will extremely vasodilator
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epinephrine
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SKM blood flow increases, skin blood flow decreases, airways in lungs increase in diameter
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3 ways to reduce blood pressure by targeting and II pathway
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ACE--> angiotensin II--> AT1R--> rhoa and rhoK
1. inhibit AT1R 2. ACE inhibitors 3. rhoa and rhoK inhibit |
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Control of vascular tone local, metabolic, hormonal, and neural control
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Hormonal--> EPI, ANGII
Neural control--> Ach, NO, NEPI Local--> ENDO, NO, H2O2, hitamine Metabolic--> CO2 build up, K, O2 decreases, adenosine, ATP |
