NUR 555 Quiz 5: Cardiovascular System | Questions
and Correct Answers plus Rationale | New Update
2026-2027 | SNHU
Question 1: In systolic heart failure, what effect does the renin-angiotensin-aldosterone
system (RAAS) have on stroke volume?
A. Decreases preload and decreases afterload
B. Decreases preload and increases afterload
C. Increases preload and decreases afterload
D. Increases preload and increases afterload
Correct Answer: D. Increases preload and increases afterload
Rationale: Activation of the RAAS in systolic heart failure increases preload through the effects
of aldosterone secretion, which promotes sodium and water retention, increasing blood volume
and venous return. RAAS also increases afterload through vasoconstriction mediated by
angiotensin II. Both of these effects worsen heart failure by increasing the workload on an
already failing heart. Option A is incorrect because RAAS increases both preload and afterload,
not decreases. Option B is incorrect because preload is increased. Option C is incorrect because
afterload is increased. The RAAS is a compensatory mechanism that initially helps maintain
cardiac output but ultimately contributes to the progression of heart failure. Blocking RAAS with
ACE inhibitors, ARBs, or aldosterone antagonists is a key treatment strategy in heart failure
management.
Question 2: A healthcare provider is assessing a patient who has a pericardial effusion and
notes a pulsus paradoxus. A student is studying how this occurs. What description by the
professional is best?
A. Blood ejected from the left atrium and reduction of blood volume in the left ventricle.
B. Blood ejected from the right atrium and reduction of blood volume in the right ventricle.
C. Diastolic filling pressures of the right ventricle and reduction of blood volume in both
ventricles.
D. Diastolic filling pressures of the left ventricle and reduction of blood volume in all four
cardiac chambers.
Correct Answer: D. Diastolic filling pressures of the left ventricle and reduction of blood
volume in all four cardiac chambers.
, Rationale: Pulsus paradoxus means that the arterial blood pressure during expiration exceeds
arterial pressure during inspiration by more than 10 mmHg. This clinical finding reflects
impairment of diastolic filling of the left ventricle plus a reduction of blood volume within all
four cardiac chambers. In pericardial effusion, the increased pressure in the pericardial sac
restricts filling of all four chambers during diastole, leading to decreased stroke volume and the
characteristic pulsus paradoxus. Option A is incorrect; it is not limited to the left atrium and
ventricle. Option B is incorrect; it is not limited to the right side. Option C is incorrect; it affects
all four chambers, not just both ventricles.
Question 3: What is the major determinant of the resistance that blood encounters as it
flows through the systemic circulation?
A. Force of ventricular contraction
B. Volume of blood in the systemic circulation
C. Muscle layer of the metarterioles
D. Muscle layer of the arterioles
Correct Answer: D. Muscle layer of the arterioles
Rationale: The major determinant of peripheral resistance is the muscle layer of the arterioles.
Arterioles are the primary site of resistance in the circulatory system. Contraction or relaxation
of the smooth muscle in the arteriolar walls changes their diameter, which directly affects
resistance. According to Poiseuille's law, resistance is inversely proportional to the fourth power
of the vessel radius, meaning small changes in arteriolar diameter have significant effects on
resistance. Option A is incorrect; the force of ventricular contraction affects cardiac output, not
resistance. Option B is incorrect; blood volume affects pressure but not resistance directly.
Option C is incorrect; metarterioles are not the primary site of resistance.
Question 4: The healthcare professional reviews an ECG of a patient with a conduction
problem. What finding would be consistent with problems with ventricular muscle cell
depolarization?
A. QT interval variability
B. Absence of P waves
C. Shortened PR interval
D. Prolonged QRS interval
Correct Answer: D. Prolonged QRS interval
Rationale: The QRS complex represents the sum of all ventricular muscle cell depolarizations.
If a patient has a conduction problem, the ECG would show a prolonged QRS interval. The
normal QRS duration is 0.08-0.12 seconds (80-120 ms). Prolongation indicates delayed
ventricular depolarization, which can occur in bundle branch blocks or other conduction
abnormalities. Option A is incorrect; QT interval variability is not specific for depolarization
and Correct Answers plus Rationale | New Update
2026-2027 | SNHU
Question 1: In systolic heart failure, what effect does the renin-angiotensin-aldosterone
system (RAAS) have on stroke volume?
A. Decreases preload and decreases afterload
B. Decreases preload and increases afterload
C. Increases preload and decreases afterload
D. Increases preload and increases afterload
Correct Answer: D. Increases preload and increases afterload
Rationale: Activation of the RAAS in systolic heart failure increases preload through the effects
of aldosterone secretion, which promotes sodium and water retention, increasing blood volume
and venous return. RAAS also increases afterload through vasoconstriction mediated by
angiotensin II. Both of these effects worsen heart failure by increasing the workload on an
already failing heart. Option A is incorrect because RAAS increases both preload and afterload,
not decreases. Option B is incorrect because preload is increased. Option C is incorrect because
afterload is increased. The RAAS is a compensatory mechanism that initially helps maintain
cardiac output but ultimately contributes to the progression of heart failure. Blocking RAAS with
ACE inhibitors, ARBs, or aldosterone antagonists is a key treatment strategy in heart failure
management.
Question 2: A healthcare provider is assessing a patient who has a pericardial effusion and
notes a pulsus paradoxus. A student is studying how this occurs. What description by the
professional is best?
A. Blood ejected from the left atrium and reduction of blood volume in the left ventricle.
B. Blood ejected from the right atrium and reduction of blood volume in the right ventricle.
C. Diastolic filling pressures of the right ventricle and reduction of blood volume in both
ventricles.
D. Diastolic filling pressures of the left ventricle and reduction of blood volume in all four
cardiac chambers.
Correct Answer: D. Diastolic filling pressures of the left ventricle and reduction of blood
volume in all four cardiac chambers.
, Rationale: Pulsus paradoxus means that the arterial blood pressure during expiration exceeds
arterial pressure during inspiration by more than 10 mmHg. This clinical finding reflects
impairment of diastolic filling of the left ventricle plus a reduction of blood volume within all
four cardiac chambers. In pericardial effusion, the increased pressure in the pericardial sac
restricts filling of all four chambers during diastole, leading to decreased stroke volume and the
characteristic pulsus paradoxus. Option A is incorrect; it is not limited to the left atrium and
ventricle. Option B is incorrect; it is not limited to the right side. Option C is incorrect; it affects
all four chambers, not just both ventricles.
Question 3: What is the major determinant of the resistance that blood encounters as it
flows through the systemic circulation?
A. Force of ventricular contraction
B. Volume of blood in the systemic circulation
C. Muscle layer of the metarterioles
D. Muscle layer of the arterioles
Correct Answer: D. Muscle layer of the arterioles
Rationale: The major determinant of peripheral resistance is the muscle layer of the arterioles.
Arterioles are the primary site of resistance in the circulatory system. Contraction or relaxation
of the smooth muscle in the arteriolar walls changes their diameter, which directly affects
resistance. According to Poiseuille's law, resistance is inversely proportional to the fourth power
of the vessel radius, meaning small changes in arteriolar diameter have significant effects on
resistance. Option A is incorrect; the force of ventricular contraction affects cardiac output, not
resistance. Option B is incorrect; blood volume affects pressure but not resistance directly.
Option C is incorrect; metarterioles are not the primary site of resistance.
Question 4: The healthcare professional reviews an ECG of a patient with a conduction
problem. What finding would be consistent with problems with ventricular muscle cell
depolarization?
A. QT interval variability
B. Absence of P waves
C. Shortened PR interval
D. Prolonged QRS interval
Correct Answer: D. Prolonged QRS interval
Rationale: The QRS complex represents the sum of all ventricular muscle cell depolarizations.
If a patient has a conduction problem, the ECG would show a prolonged QRS interval. The
normal QRS duration is 0.08-0.12 seconds (80-120 ms). Prolongation indicates delayed
ventricular depolarization, which can occur in bundle branch blocks or other conduction
abnormalities. Option A is incorrect; QT interval variability is not specific for depolarization
