cardio 2 Flashcards
describe the order from impulse at SA to ventricular contracttion
SA -> ATRIA -> AV NODE -> boh -> purkinje -> ventricles
what is desirable for the treatment of supraventricular arrhythmias
AV block
where are the fast cardiac APs
purkinje, atria, ventricles
describe the phases of a fast AP
0 = Na goes in
I = Na goes in to a lesser extent
II = Na and Ca through channels, Na/Ca exchange
III = K goes out (final repolarization(
IV = pacemaker depolarization, Na/K dependent, HCN channels, ionic gradients
desrcibe the phases of a slow AP
0 = Na and Ca in
III = K out
IV = Ca dependent pacemaker
What is described by
P
QRS
T
P-R
Q-T
atrial depol
ventricular depol
ventricular repol
av conduction time
duration of ventricular AP
what is chronotropy
frequency of impulse formation
what is inotropy
strength of contraction
how do sympathetic affects change the slope of Phase IV in SA
positive chronotropic
what phase does a inotropic effect affect
Phase II
how does a positive inotropic effect affect the APs`
increase Ca through L-type
how do sympathetics affect AV conduction, how does this affect the P-R
increase AV conduction
decrease P-R
how do sympathetics affect ventricular AP duration
shortens, higher heart rate
how does sympathetic affect Purkinje fibres?
increase rhythmicitty, increasing slope, quicker threshold
what is the consequence of calcium overload
EADs DADs
what nerve is most significant in parasympathetic signalling to the heart
vagus
what receptors are responsible for parasympathetic activity on the heart
M2
what is the mechanism behind M2
Gi
do parasympathetic signaling have an inotropic effect `
nah
what affect does parasympathetic signaling have on the heart
negative chronotropic
atria
AV node
which node is responsible for the chronotopics effect of parasympathetic signaling
SA node
