NUR 612 CHAPTER 28 NOTEBOOK FLASHCARDS
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QUESTIONS &ANSWERS. EXCELLENCE GUARANTEED.
Primary Pacemaker of the Heart Answer: Sinoatrial (SA) node, with an intrinsic rate of 60 to
100 beats/min.
Purpose of AV Node Delay Answer: Allows atria to complete ejection of blood before
ventricular contraction begins.
Intrinsic Rate of Purkinje Fibers Answer: 15 to 40 beats/min.
Automaticity Answer: Ability of cardiac cells to spontaneously initiate an action potential
without external stimulation.
Phase 0 of Fast-Response Cardiac Action Potential Answer: Characterized by rapid influx of
sodium (Na⁺) ions.
Ion Channel Responsible for Phase 2 (Plateau Phase) Answer: L-type calcium (Ca⁺⁺) channels.
Phase 3 of Cardiac Action Potential Answer: Rapid repolarization caused primarily by efflux of
potassium (K⁺) ions.
Phase 4 Spontaneous Depolarization (SA Node) Answer: Largely attributed to the funny (If)
current.
Absolute Refractory Period Answer: Period (Phases 0-3) when the cell cannot depolarize under
any circumstances.
Supernormal Excitatory Period Answer: End of Phase 3 where weak stimulus can evoke
abnormal responses/arrhythmias.
P Wave Answer: Represents atrial depolarization on a surface ECG.
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, Normal PR Interval Duration Answer: 0.12 to 0.20 seconds.
QRS Complex Answer: Represents ventricular depolarization on an ECG.
ST Segment Answer: ECG segment coinciding with Phase 2 (plateau phase) of ventricular
action potential.
T Wave Answer: Represents ventricular repolarization on an ECG.
Clinical Significance of Prolonged QT Interval Answer: Increases the risk for Torsade de
pointes.
Reentry Mechanism Answer: Electrical impulse continuously circulates through slow
conduction and unidirectional block.
Sinus Bradycardia Answer: Heart rate less than 60 beats/min originating from the SA node.
Sinus Tachycardia Answer: Heart rate greater than 100 beats/min originating from the SA node.
Sick Sinus Syndrome (SSS) Hallmark Answer: Alternating periods of bradycardia and various
tachyarrhythmias.
Premature Atrial Contractions (PACs) Answer: Early atrial contractions interrupting normal
sinus rhythm; caused by stress, caffeine, tobacco.
Atrial Flutter ECG Pattern Answer: Regular 'sawtooth' pattern with atrial rate typically around
300 beats/min.
Atrial Fibrillation Ventricular Response Answer: Described as irregularly irregular.
Atrial Fibrillation Clinical Concern Answer: Thrombus formation in left atrial appendage
leading to embolic stroke.
Pulse Deficit Answer: Difference between apical heart rate and palpable peripheral pulse rate.
2
APPHIA - Crafted with Care and Precision for Academic Excellence.
|COMPLETE STUDY GUIDE WITH 100% ACCURATE
QUESTIONS &ANSWERS. EXCELLENCE GUARANTEED.
Primary Pacemaker of the Heart Answer: Sinoatrial (SA) node, with an intrinsic rate of 60 to
100 beats/min.
Purpose of AV Node Delay Answer: Allows atria to complete ejection of blood before
ventricular contraction begins.
Intrinsic Rate of Purkinje Fibers Answer: 15 to 40 beats/min.
Automaticity Answer: Ability of cardiac cells to spontaneously initiate an action potential
without external stimulation.
Phase 0 of Fast-Response Cardiac Action Potential Answer: Characterized by rapid influx of
sodium (Na⁺) ions.
Ion Channel Responsible for Phase 2 (Plateau Phase) Answer: L-type calcium (Ca⁺⁺) channels.
Phase 3 of Cardiac Action Potential Answer: Rapid repolarization caused primarily by efflux of
potassium (K⁺) ions.
Phase 4 Spontaneous Depolarization (SA Node) Answer: Largely attributed to the funny (If)
current.
Absolute Refractory Period Answer: Period (Phases 0-3) when the cell cannot depolarize under
any circumstances.
Supernormal Excitatory Period Answer: End of Phase 3 where weak stimulus can evoke
abnormal responses/arrhythmias.
P Wave Answer: Represents atrial depolarization on a surface ECG.
1
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, Normal PR Interval Duration Answer: 0.12 to 0.20 seconds.
QRS Complex Answer: Represents ventricular depolarization on an ECG.
ST Segment Answer: ECG segment coinciding with Phase 2 (plateau phase) of ventricular
action potential.
T Wave Answer: Represents ventricular repolarization on an ECG.
Clinical Significance of Prolonged QT Interval Answer: Increases the risk for Torsade de
pointes.
Reentry Mechanism Answer: Electrical impulse continuously circulates through slow
conduction and unidirectional block.
Sinus Bradycardia Answer: Heart rate less than 60 beats/min originating from the SA node.
Sinus Tachycardia Answer: Heart rate greater than 100 beats/min originating from the SA node.
Sick Sinus Syndrome (SSS) Hallmark Answer: Alternating periods of bradycardia and various
tachyarrhythmias.
Premature Atrial Contractions (PACs) Answer: Early atrial contractions interrupting normal
sinus rhythm; caused by stress, caffeine, tobacco.
Atrial Flutter ECG Pattern Answer: Regular 'sawtooth' pattern with atrial rate typically around
300 beats/min.
Atrial Fibrillation Ventricular Response Answer: Described as irregularly irregular.
Atrial Fibrillation Clinical Concern Answer: Thrombus formation in left atrial appendage
leading to embolic stroke.
Pulse Deficit Answer: Difference between apical heart rate and palpable peripheral pulse rate.
2
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