NURS 6501N WEEK 7 QUIZ (NEW-2024): ADVANCED
PATHOPHYSIOLOGY: WALDEN UNIVERSITY
The cardiac electrical impulse normally begins spontaneously in the sinoatrial (SA) node
because of what reason? a. It has a superior location in the right atrium.
b. It is the only area of the heart capable of spontaneous depolarization.
c. It has rich sympathetic innervation via the vagus nerve.
d. It depolarizes more rapidly than other automatic cells of the heart. -
✔✔ANSW✔✔..ANS: D
The electrical impulse normally begins in the SA node because its cells depolarize more
rapidly than other automatic cells at a rate of 60 to 100 beats/min. The SA node's
location does not influence this activity. Other areas of the heart include the AV node
and the Purkinje fibers. The vagus nerve causes the heart rate to slow as part of the
parasympathetic nervous system.
1. What period follows depolarization of the myocardium and represents a period during
which no new cardiac potential can be propagated?
a. Refractory
b. Hyperpolarization
c. Threshold
d. Sinoatrial (SA) - ✔✔ANSW✔✔..ANS: A
During the absolute refractory period, no new cardiac action potential can be initiated by
a stimulus. The other options do not reflect the time period in which no stimulation will
produce a new cardiac potential.
1. A patient has a disorder affecting ventricular depolarization. What ECG finding would
the healthcare professional associate with this condition?
a. Shortened PR interval
b. Prolonged QRS interval
c. QT interval variability
d. Absence of P waves - ✔✔ANSW✔✔..ANS: B
The QRS complex represents the sum of all ventricular muscle cell depolarizations. If a
patient had ECG findings suggestive of problems with this activity, there would be
prolongation of the QRS interval. The PR interval reflects the amount of time needed for
the action potential to travel from the atrium to the ventricle. QT interval variability is
normal. An absence of P waves would indicate a problem with the SA node.
, 1. What can shorten the conduction time of action potential through the atrioventricular
(AV) node?
a. Parasympathetic nervous system
b. Catecholamines
c. Vagal stimulation
d. Sinoatrial node (SA) - ✔✔ANSW✔✔..ANS: B
Catecholamines speed the heart rate, shorten the conduction time through the AV node,
and increase the rhythmicity of the AV pacemaker fibers. The vagal nerve is part of the
sympathetic nervous system and stimulation will decrease heart rate. The SA node is
responsible for generating the electrical activity of the heart, but is not responsible for
the time it takes for it to travel through the AV node.
1. A patient had a myocardial infarction that damaged the SA node, which is no longer
functioning as the pacemaker of the heart. What heart rate would the healthcare
provider expect the patient to have? a. 60 to 70 beats/min
b. 40 to 60 beats/min
c. 30 to 40 beats/min
d. 10 to 20 beats/min - ✔✔ANSW✔✔..ANS: B
If the SA node is damaged, then the AV node will become the heart's pacemaker at a
rate of approximately 40 to 60 spontaneous depolarizations per minute. The SA node
normally fires at a rate of 60 to 100 beats/min. The Purkinje fibers can function as the
heart's pacemaker and will fire at a rate of around 40 beats/min.
1. What is the effect of epinephrine on β3 receptors on the heart?
a. Decreases coronary blood flow
b. Supplements the effects of both β1 and β2 receptors
c. Increases the strength of myocardial contraction
d. Prevents overstimulation of the heart by the sympathetic nervous system -
✔✔ANSW✔✔..ANS: D
β3 receptors are found in the myocardium and coronary vessels. In the heart,
stimulation of these receptors opposes the effects of β1- and β2-receptor stimulation
and negative inotropic effect. Thus β3 receptors may provide a safety mechanism that
decreases myocardial contractility to prevent overstimulation of the heart by the
sympathetic nervous system.
1. Where in the heart are the receptors for neurotransmitters located?
a. Semilunar and atrioventricular (AV) valves
b. Endocardium and sinoatrial (SA) node
c. Myocardium and coronary vessels
d. Epicardium and AV node - ✔✔ANSW✔✔..ANS: C
1. Which statement made by a student indicates the healthcare professional needs to
describe the pericardium again?
PATHOPHYSIOLOGY: WALDEN UNIVERSITY
The cardiac electrical impulse normally begins spontaneously in the sinoatrial (SA) node
because of what reason? a. It has a superior location in the right atrium.
b. It is the only area of the heart capable of spontaneous depolarization.
c. It has rich sympathetic innervation via the vagus nerve.
d. It depolarizes more rapidly than other automatic cells of the heart. -
✔✔ANSW✔✔..ANS: D
The electrical impulse normally begins in the SA node because its cells depolarize more
rapidly than other automatic cells at a rate of 60 to 100 beats/min. The SA node's
location does not influence this activity. Other areas of the heart include the AV node
and the Purkinje fibers. The vagus nerve causes the heart rate to slow as part of the
parasympathetic nervous system.
1. What period follows depolarization of the myocardium and represents a period during
which no new cardiac potential can be propagated?
a. Refractory
b. Hyperpolarization
c. Threshold
d. Sinoatrial (SA) - ✔✔ANSW✔✔..ANS: A
During the absolute refractory period, no new cardiac action potential can be initiated by
a stimulus. The other options do not reflect the time period in which no stimulation will
produce a new cardiac potential.
1. A patient has a disorder affecting ventricular depolarization. What ECG finding would
the healthcare professional associate with this condition?
a. Shortened PR interval
b. Prolonged QRS interval
c. QT interval variability
d. Absence of P waves - ✔✔ANSW✔✔..ANS: B
The QRS complex represents the sum of all ventricular muscle cell depolarizations. If a
patient had ECG findings suggestive of problems with this activity, there would be
prolongation of the QRS interval. The PR interval reflects the amount of time needed for
the action potential to travel from the atrium to the ventricle. QT interval variability is
normal. An absence of P waves would indicate a problem with the SA node.
, 1. What can shorten the conduction time of action potential through the atrioventricular
(AV) node?
a. Parasympathetic nervous system
b. Catecholamines
c. Vagal stimulation
d. Sinoatrial node (SA) - ✔✔ANSW✔✔..ANS: B
Catecholamines speed the heart rate, shorten the conduction time through the AV node,
and increase the rhythmicity of the AV pacemaker fibers. The vagal nerve is part of the
sympathetic nervous system and stimulation will decrease heart rate. The SA node is
responsible for generating the electrical activity of the heart, but is not responsible for
the time it takes for it to travel through the AV node.
1. A patient had a myocardial infarction that damaged the SA node, which is no longer
functioning as the pacemaker of the heart. What heart rate would the healthcare
provider expect the patient to have? a. 60 to 70 beats/min
b. 40 to 60 beats/min
c. 30 to 40 beats/min
d. 10 to 20 beats/min - ✔✔ANSW✔✔..ANS: B
If the SA node is damaged, then the AV node will become the heart's pacemaker at a
rate of approximately 40 to 60 spontaneous depolarizations per minute. The SA node
normally fires at a rate of 60 to 100 beats/min. The Purkinje fibers can function as the
heart's pacemaker and will fire at a rate of around 40 beats/min.
1. What is the effect of epinephrine on β3 receptors on the heart?
a. Decreases coronary blood flow
b. Supplements the effects of both β1 and β2 receptors
c. Increases the strength of myocardial contraction
d. Prevents overstimulation of the heart by the sympathetic nervous system -
✔✔ANSW✔✔..ANS: D
β3 receptors are found in the myocardium and coronary vessels. In the heart,
stimulation of these receptors opposes the effects of β1- and β2-receptor stimulation
and negative inotropic effect. Thus β3 receptors may provide a safety mechanism that
decreases myocardial contractility to prevent overstimulation of the heart by the
sympathetic nervous system.
1. Where in the heart are the receptors for neurotransmitters located?
a. Semilunar and atrioventricular (AV) valves
b. Endocardium and sinoatrial (SA) node
c. Myocardium and coronary vessels
d. Epicardium and AV node - ✔✔ANSW✔✔..ANS: C
1. Which statement made by a student indicates the healthcare professional needs to
describe the pericardium again?
