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what layer of the heart contains the main coronary arteries
what are the three layers of the heart (inner to outer)
endocardium, myocardium, pericardium
what are the names and locations of the 2 AV valves
tricuspid on right, bicuspid (mitral) on left
what are the names and locations of the 2 semi lunar valves
pulmonic on right side, aortic on left side
during what phase of the cardiac cycle do the coronary arteries fill with blood
what is a chronotropic effect
change in heart rate
what is an inotropic effect
change in contractility
what is a dromotropic effect
speed of conduction through the AV junction
what parts of the hear are supplied by parasympatheic nerve fibers
SA node, AV node, and atrial muscle
what parts of the heart are supplied by sympathetic nerves
parts of electrical system, atrial muscle, and ventricular myocardium
what 3 factors determine stroke volume
preload (ventricular filling), afterload, myocardium's contractile state
what 3 factors influence afterload
arterial blood pressure, arterial distensibility, arterial resistance
what is the Frank-Starling law of the heart
preload causes stretching of muscle fiber which causes increased contractility
what ion leaks out of the cell at rest
which type of cardiac cell has more Na channels, conduction cells or SA and AV nodes
conduction cells
on the ECG what indicates the absolute refractory period
QRS to mid T
on the ECG what indicates the relative refractory period
middle T to end of T
on the ECG when does the supernormal period occur
end of phase 3 to the beginning of phase 4; the END of the T wave
what is the normal progression of the electrical impulse
SA node, atrial muscle, intraatrial septum, Bachmans bundle, left atrium, AV node, bundle of His, Bundle branches, Purkinje fibers
what is the AV junction
AV node and the non branching portion of the bundle of His
what is it called when the AV junctin is bypassed
accessory pathway
what artery supplies the AV node in 85-90% of the population
how is blood supplied to the bundle of His
branches of the left anterior and posterior descending coronary arteries
what is the firing rate of the AV junction
what is the rate of the purkinje fibers
what 3 conditions must be present for reentry to occur
a potential conduction circuit or circular conduction pathway, a block within part of the circuit, delayed conduction with the remainder of the circuit
what term describes when the SA node slows or fails to initiate depolarization or spontaneously produces electrical imulses
x of y cards