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15 Cards in this Set
- Front
- Back
where is cardiac muscles
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myocardium of heart
functional syncytium vs true syncytium |
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Autonomic NS regulates but does NOT generate cardiac rhythm
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cardiac rhythm is by SA AV AV nodes purkinjke fibers
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Cardiac in light microscope
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branch
intercalated discs capillaries mono-bi nucleate, centrally located fiber sizes vary but not as much as smooth muscle |
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Cardiac Electron microscope
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greatest amounts of mito
glycogen, but less than skeletal sarcomeres SR not as extensive, dyad intercalated discs step like |
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telling the difference between atria and ventricle
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atria: narrower
ventricle: large diam, wider T tubule at Z band |
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Intercalated discs
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where Z line would normally be
step like b/c not all myofibrils in a cardiac myocyte are equal length -longitudinal(gap junxns) -transverse(Fascia adherens-thin filaments (desomosomes-macula adherenns intermediate filaments) |
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Components of the conduction system
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SA -> AV -> purkinje fibers in bundle of his
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characteristics of
SA/AV Purkinje |
SA/AV - smaller in diam, sep by CT, but attached in certain places by gap, oscillating mem pot
purkinje - larger diam, more glycogen(paler), branching bundles run under endocardium and make gap junxns with ventricular myocytes |
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SMOOTH MUSCLE
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the most recently evolved contractile tissue
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Smooth muscle structure
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spindle
central elongated nucleus CORKSCREW en passant boutan of autonomic NS axons SMALL diam |
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smooth muscle ultrastructure
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gap junxns(some sm muscle is innervated individually like iris for maximal control)
caveolae(t tubule) dense bodies(Z lines)alpha actinin and vimentin |
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smooth muscle myosin II arrangement
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sidepolar instead of bipolar
tail to tail but with heads pointing in opposite directiong |
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describe ca influc in smooth muscle
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main source is extracellular Ca
binds calmodulin(not tnC), activates MLCK --> P-myosin regulatory light chain deP'd by myosin phosphatase |
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Thick filament smooth muscle
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no bare zone
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Smooth muscle oddities
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can divide, makes collagen and elastin
Tubular - layers Sac like - interlacing bundles |