NURS 5315 Exam 3 Cardiovascular/Pulmonary Questions With Completed Solutions 2025.

NURS 5315 Exam 3
Cardiovascular/Pulmonary

phase 0 bundle of His/Purkinje fibers - ANS-depolarization from open Ca channels. Na
channels inactivated bc of less negative RMP of cells than their membrane counterparts.
slow conduction of impulse by AV node that prolongs transmission from atria to the ventricle
\Phase 0 of cardiac action potential - ANS-rapid depolarization due to rapid influx of Na
when Na channels open
- P Wave (Atrial Contraction)
\Phase 1 of cardiac action potential - ANS-Early cellular repolarization begins during this
phase as Na channels close, potassium channels open and K exits the intracellular space.
\Phase 2 of cardiac action potential - ANS-Plateau phase where in there is K+ efflux
balanced by Ca2+ influx by temporary plateau in repolarization; more calcium in
sarcoplasmic reticulum causing myocardial contraction
\Phase 3 of cardiac action potential - ANS-Rapid repolarization with massive efflux of K+
with opening of voltage gated K channels open and voltage gated Ca channels close
causing rapid repolarization
\Phase 4 of cardiac action potential - ANS-resting membrane potential -85mV; high K
permeability from the K channels.
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