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10 Cards in this Set

  • Front
  • Back
membrane pot of sinus node
-55 to -60mV
sinus node has slow leak of _____ at rest pot of -55mV
Na ions
why is the SA node at a more positive resting pot than ventricular muscle?
leaky to Na and Ca ions
conduction velocity of atrial and ventricular muscle?
0.3 to 0.5 m/s
conduction velocity of purkinje fibers?
2 to 4 m/s
the cardiac pacemaker
SA node
autorhythmicity is due to _______
leakiness to ions (sodium)
depolarization of the SA node is due to_________
opening of the slow calcium channels (h gates closed)
Each time A-V conduction ceases, the ventricles often do not start their own beating until after a delay of 5 to 30 seconds. This results from the phenomenon called ___________
overdrive suppression
stokes-adams syndrome
periodic fainting spells cuased by intermittant A-V block. (Overdrive suppression causes fainting, ventricular escape causes recovery)