Heart Phys yo Flashcards
Which walls are fed by the L coronary artery?
lateral wall
anterior wall
Which walls are fed by the R coronary artery?
inferior wall
posterior wall
(I’m pretty sure these are right - please tell me if I’m wrong!)
Where is the worst place to have an infarction?
anterior wall
What are the 3 types of heart cells?
myocardial
pacemakers
specialized conducting cells (e.g. bundle of his, purkinje fibers)
What happens during a normal action potential?
(there is a picture on the other side)
What happens during the action potential of the SA/AV nodes?
(another picture)
What is the term for when no stimulation will depolarize cells?
absolute refractory period
What is the term for when only a very strong stimulus will depolarize cells?
relative refractory period
What are the parasympathetic HRs for the SA node, AV node, and Purkinje fibers?
SA - 60-100
AV - 40-60
Purkinje - 20-40x/min
Does conduction velocity occur faster in the LBBB or RBBB?
LBBB
What causes ventricular myocytes to depolarize?
Na entering the cell
Which wall is opposite to the inferior wall?
Lateral wall
Which ion is primarily responsible for depolarizing the AV node?
calcium
Which system inc HR, inc conduction velocity, and inc the force of contraction?
With what neurotransmitters?
sympathetic
NE, EPI
Which system dec HR and dec conduction velocity?
With what neurotransmitter?
parasympathetic
Ach
Do you have a lower threshold at rest or exercise?
rest
how do waves of depolarization and repolarization travel across the cells?
gap junctions
What kind of a deflection do you get when a vector travels toward a + electrode?
a - electrode?
toward + electrode = + EKG
toward - electrode = - EKG
What does the EKG look like when a vector travels @ 90 degrees of it
biphasic
Starting with the AV valve closing, what is the order of events with regards to the opening and closing of the AV valve/aortic valve and the filling of the ventricles?
1) AV valve closes
2) Ventricles are filled and begin isovolumic contraction
3) Aortic valve opens
4) Ventricles eject blood into aortic valve (systole)
5) Aortic valve closes
6) Isovolumetric relaxation occurs in the ventricles
7) AV valve opens
8) Diastole occurs (blood fills the ventricles)
When the AV valve closes, what is happening:
a) to the atrial pressure?
b) to the ventricular pressure?
c) to ventricular volume?
a) atrial pressure slightly increases (due to slamming shut)
b) ventricular pressure greatly increases (isovolumic contraction occurs)
c) ventricular volume is highest
When the aortic valve opens, what is happening:
a) to the aortic pressure?
b) to the atrial pressure?
c) to the ventricular pressure?
d) to ventricular volume?
a) aortic pressure increases
b) atrial pressure starts to decrease (because the ventricles aren’t pushing up on them as they eject)
c) ventricular pressure continues to increase (as it squeezes)
d) ventricular volume greatly decreases