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15 Cards in this Set

  • Front
  • Back
where is cardiac muscles
myocardium of heart

functional syncytium vs true syncytium
Autonomic NS regulates but does NOT generate cardiac rhythm
cardiac rhythm is by SA AV AV nodes purkinjke fibers
Cardiac in light microscope
intercalated discs
mono-bi nucleate, centrally located
fiber sizes vary but not as much as smooth muscle
Cardiac Electron microscope
greatest amounts of mito
glycogen, but less than skeletal
SR not as extensive, dyad
intercalated discs step like
telling the difference between atria and ventricle
atria: narrower
ventricle: large diam,
wider T tubule at Z band
Intercalated discs
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)
Components of the conduction system
SA -> AV -> purkinje fibers in bundle of his
characteristics of
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
the most recently evolved contractile tissue
Smooth muscle structure
central elongated nucleus CORKSCREW
en passant boutan of autonomic NS axons
SMALL diam
smooth muscle ultrastructure
gap junxns(some sm muscle is innervated individually like iris for maximal control)

caveolae(t tubule)
dense bodies(Z lines)alpha actinin and vimentin
smooth muscle myosin II arrangement
sidepolar instead of bipolar
tail to tail but with heads pointing in opposite directiong
describe ca influc in smooth muscle
main source is extracellular Ca
binds calmodulin(not tnC), activates MLCK --> P-myosin regulatory light chain

deP'd by myosin phosphatase
Thick filament smooth muscle
no bare zone
Smooth muscle oddities
can divide, makes collagen and elastin

Tubular - layers
Sac like - interlacing bundles