Download PreLab Questions PreLab Questions Score: List the structures of the

PreLab Questions
PreLab Questions
Score:
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1. List the structures of the cardiac conduction system starting with the SA node:
SA node
AV node
AV bundle of His
Rt and Lt bundle branches
purkinje fibers
2. Match the following with its description:
a.
b.
3.
P wave
P-R interval
c.
d.
T wave
QRS complex
e.
f.
S-T segment
Q-T interval
c
represents ventricular repolarization
b
time from the onset of atrial depolarization to the onset of ventricular depolarization
a
represents atrial depolarization
e
time from the end of ventricular depolarization to the onset of ventricular repolarization
d
represents ventricular depolarization
f
time from the onset of ventricular depolarization to the end of ventricular repolarization
How many small blocks on the horizontal axis ECG tracing represent 1 second (assume that
the chart speed is 25 mm/second)?
25
4.
Why is it important to remain still while ECG recordings are made? Because skeletal muscle also
generates action potential, these can be detected by the EKG machine
5.
Why isn’t there a wave on a normal ECG tracing that represents atrial repolarization?
Because atria repolarize at the same time as the ventricles depolarize. So it is masked by the
ventricular depolarization
6.
What might a longer than normal P-R interval indicate? Indicates a delay or abnormality in the
conduction pathway
7.
What variable does a plethysmograph measure?
heart rate