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39 Cards in this Set
- Front
- Back
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Location of the Sa node
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Junction if the superior vena cava and right atrium
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Sa node is supplied by the
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60% right coronary and 40% left circumflex
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Connexins
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Proteins that isolate the Sa node electrically from the atrium and allow current passage out
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Location of the av node
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Wall of right atrium endocardium, anterior to r coronary sinus, above septal leaflet of the tricuspid valve, triangle of Koch
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What supplies the av node
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85% RCA
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Av node cell structure
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Small spherical cells that interweave in whorls of fasciculi
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What is the only normal communication between the atria and ventricles?
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Bundle of his
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Blood supply for bundle of his
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RCA and left circumflex
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Left anterior fascicle
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Anterior and superior aspects of lv, single stranded fiber easily blocked
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Left posterior fascicle
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Posterior and inferior parts of lv, fan of fibers, more difficult to block
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Fastest fiber
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Purkinje
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Slow response action potentials found in
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Sa and av node and junction all tissue
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Fast response action potentials
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Atrial tissue, atrial intermodal tracts, ventricles, ventricular contraction tissue
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Most important molecule for resting membrane potential
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K
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Equilibrium potential
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The potential difference across the membrane required to maintain the concentration gradient
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What is the equilibrium potential with k
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-96
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What is the equilibrium potential for na
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52
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What is resting membrane potential for most cardiac cells
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-90
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What ion is most permeable during resting conditions
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K
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Na is _____ impermeable at the cell membrane
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Relatively
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ATP na/k pump
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3 na out and 2 k in, located in thebsacrolemma, inhibits by digitalis
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ATP dependent na/ca pump
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3 na in and 1 ca out
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Hypoxia effect in pump
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Decreased ATP and disables pump leads to increased intracellular calcium
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Phase 4 rests at what equilibrium potential
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K
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Phase 0
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Fast na channel inward current, com slow ca
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Phase 1
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Transient k out channel, slow ca channels, flats sodium channels close, occurs only in non pacemaker cells
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Long lasting ca channel
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L type
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Pacemaker cells
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Spontaneous action potentials, no true resting potential, it is current change that is the result if slow l type ca channels that is key to pacemaker function
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Pacemaker cells depolarization from -55 to -40 occurs via
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Funny na channels
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Kach channels
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Leak k out of cell, hyper polarization
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Acetylcholinesterase acts on
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Atria, Sa and av nodes
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Fatal stimulation decreases the slope of what phase
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4, hyperpolarization
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Norepinephrine binds to
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Beta1adenorecptirs increasing camp
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Carotid sinuses send messages to the brain via
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9
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What binds to ca
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Troponin c, inhibited by troponin I
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Is atrial or ventricular refractory rates faster
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Atrial
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Increased k does what to the resting potential
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Raises it
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Hypokalimia results in prolonged what wave
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U
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The 6 leads analyze along what type of cut
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Coronal
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