Cardiac Electrophysiology Exam
Questions and Answers Graded A+
Contractile cells - Correct answer-majority cells of atria and ventricle; generate
force or pressure (cardiac working cells)
Conducting cells - Correct answer-sinoatrial (SA) node; atrial internodal tracts;
atrioventricular (AV) node; bundle of HIS; Purkinje system
Conducting cells have the intrinsic - Correct answer-capacity to spontaneously
generate action potentials
Sinoatrial (SA) node - Correct answer-normal pacemaker of the heart; origin of
each normal heartbeat.
Atrial internodal tracts and atria - Correct answer-internodal pathways that spread
the action potential of the SA node to the left and right atria
Atrioventricular (AV) node - Correct answer-only electrical communication
between atria and ventricles; slow conduction; ensures complete atrial contraction
before ventricle activation
, The atrioventricular (AV) node is continuous with - Correct answer-the ventricular
conducting system
Ventricular conducting system - Correct answer-bundle of His (atrioventricular
bundle); left and right bundle branches; Purkinje fibers
Increasing the conduction velocity of the AV node - Correct answer-decreases
ventricular filling, stroke volume, and cardiac output
Normal sinus rhythm - Correct answer-action potential originates in SA node; SA
nodal impules ~60-80/min; myocardium activation sequentially timed
Compared to skeletal muscle, cardiac muscle has - Correct answer-longer
refractory periods; sustained periods of depolarization (plateaus)
Longer refractory periods - Correct answer-maintain normal sinus rhythm; prevent
arrhythmias
Responsiveness relationship - Correct answer-relationship between the rate of rise
of upstroke and resting membrane potential
Responsiveness relationship is greatest when - Correct answer-the membrane is
hyperpolarized; fewer inactivation gates closed
Questions and Answers Graded A+
Contractile cells - Correct answer-majority cells of atria and ventricle; generate
force or pressure (cardiac working cells)
Conducting cells - Correct answer-sinoatrial (SA) node; atrial internodal tracts;
atrioventricular (AV) node; bundle of HIS; Purkinje system
Conducting cells have the intrinsic - Correct answer-capacity to spontaneously
generate action potentials
Sinoatrial (SA) node - Correct answer-normal pacemaker of the heart; origin of
each normal heartbeat.
Atrial internodal tracts and atria - Correct answer-internodal pathways that spread
the action potential of the SA node to the left and right atria
Atrioventricular (AV) node - Correct answer-only electrical communication
between atria and ventricles; slow conduction; ensures complete atrial contraction
before ventricle activation
, The atrioventricular (AV) node is continuous with - Correct answer-the ventricular
conducting system
Ventricular conducting system - Correct answer-bundle of His (atrioventricular
bundle); left and right bundle branches; Purkinje fibers
Increasing the conduction velocity of the AV node - Correct answer-decreases
ventricular filling, stroke volume, and cardiac output
Normal sinus rhythm - Correct answer-action potential originates in SA node; SA
nodal impules ~60-80/min; myocardium activation sequentially timed
Compared to skeletal muscle, cardiac muscle has - Correct answer-longer
refractory periods; sustained periods of depolarization (plateaus)
Longer refractory periods - Correct answer-maintain normal sinus rhythm; prevent
arrhythmias
Responsiveness relationship - Correct answer-relationship between the rate of rise
of upstroke and resting membrane potential
Responsiveness relationship is greatest when - Correct answer-the membrane is
hyperpolarized; fewer inactivation gates closed
