Saunders Comprehensive Review for the NCLEX-PN®
Examination
9th Edition
• Author(s)Linda Anne Silvestri; Angela Silvestri
ANATOMY AND PHYSIOLOGY TEST BANK
1) Cardiovascular — Cardiac output and preload
A 68-year-old client with chronic heart failure arrives for follow-
up. The nurse knows that an increase in venous return (preload)
will most directly increase which of the following?
A. Heart rate
B. Stroke volume
C. Systemic vascular resistance
D. Aortic valve opening pressure
Correct: B. Stroke volume
Rationale — Correct: According to the Frank-Starling
mechanism, increased venous return stretches myocardial
fibers, producing a stronger contraction and increasing stroke
volume (SV). SV × heart rate = cardiac output; thus preload
primarily affects SV.
Rationale — Incorrect:
A. Heart rate is regulated mainly by autonomic input and
,circulating catecholamines, not directly by preload.
C. Systemic vascular resistance is a function of arteriolar tone
(afterload), not preload.
D. Aortic valve opening depends on left ventricular systolic
pressure exceeding aortic pressure (afterload), not directly on
venous return.
2) Respiratory — V/Q matching
A client with a pulmonary embolus develops sudden shortness
of breath and hypoxemia. Which physiological change best
explains the hypoxemia in pulmonary embolism?
A. Right-to-left intracardiac shunt
B. Decreased ventilation to an area with normal perfusion (low
V/Q)
C. Decreased perfusion to an area with normal ventilation (high
V/Q)
D. Decreased alveolar diffusion capacity in all alveoli
Correct: C. Decreased perfusion to an area with normal
ventilation (high V/Q)
Rationale — Correct: A pulmonary embolus blocks blood flow
to regions of the lung, causing ventilation without perfusion
(high ventilation/perfusion ratio, V/Q). This produces
physiologic dead space and impairs oxygen uptake systemically,
causing hypoxemia.
Rationale — Incorrect:
,A. A right-to-left intracardiac shunt bypasses pulmonary
oxygenation but is not caused by PE.
B. Decreased ventilation with normal perfusion (low V/Q)
occurs in airway obstruction or pneumonia, not PE.
D. Diffusion capacity may be affected in interstitial disease but
PE causes perfusion defects rather than global alveolar diffusion
impairment.
3) Renal — Acid-base and bicarbonate reabsorption
A client with chronic diarrhea develops metabolic acidosis.
Which renal compensation would the nurse expect?
A. Increased bicarbonate reabsorption in proximal tubules
B. Decreased ammonium (NH4+) excretion
C. Increased hydrogen ion secretion and increased NH4+
production
D. Increased filtered bicarbonate load
Correct: C. Increased hydrogen ion secretion and increased
NH4+ production
Rationale — Correct: In metabolic acidosis the kidney increases
H⁺ secretion in distal nephron and generates new bicarbonate—
partly via increased ammoniagenesis (NH4+ production) in
proximal tubules—thus increasing NH4+ excretion and
reclaiming bicarbonate to correct acidosis.
Rationale — Incorrect:
A. While bicarbonate reabsorption is important, in acidosis the
, kidney generates new bicarbonate rather than simply increasing
reabsorption alone.
B. The kidney increases, not decreases, ammonium excretion
during acidosis.
D. Filtered bicarbonate depends on plasma bicarbonate
concentration; acidosis lowers plasma bicarbonate, so filtered
load is not increased.
4) Endocrine — Thyroid hormone effects
A 36-year-old woman with hyperthyroidism reports
palpitations, heat intolerance, and weight loss. Which
mechanism best explains her tachycardia?
A. Increased vagal tone from thyroid hormone stimulation
B. Upregulation of β-adrenergic receptors and increased
sensitivity to catecholamines
C. Direct blockade of AV node conduction by thyroid hormone
D. Decreased myocardial oxygen demand
Correct: B. Upregulation of β-adrenergic receptors and
increased sensitivity to catecholamines
Rationale — Correct: Thyroid hormones increase expression of
β-adrenergic receptors and enhance sympathetic sensitivity,
leading to increased heart rate and contractility (tachycardia).
Rationale — Incorrect:
A. Vagal tone decreases heart rate; thyroid hormone increases
sympathetic responsiveness rather than vagal tone.
Examination
9th Edition
• Author(s)Linda Anne Silvestri; Angela Silvestri
ANATOMY AND PHYSIOLOGY TEST BANK
1) Cardiovascular — Cardiac output and preload
A 68-year-old client with chronic heart failure arrives for follow-
up. The nurse knows that an increase in venous return (preload)
will most directly increase which of the following?
A. Heart rate
B. Stroke volume
C. Systemic vascular resistance
D. Aortic valve opening pressure
Correct: B. Stroke volume
Rationale — Correct: According to the Frank-Starling
mechanism, increased venous return stretches myocardial
fibers, producing a stronger contraction and increasing stroke
volume (SV). SV × heart rate = cardiac output; thus preload
primarily affects SV.
Rationale — Incorrect:
A. Heart rate is regulated mainly by autonomic input and
,circulating catecholamines, not directly by preload.
C. Systemic vascular resistance is a function of arteriolar tone
(afterload), not preload.
D. Aortic valve opening depends on left ventricular systolic
pressure exceeding aortic pressure (afterload), not directly on
venous return.
2) Respiratory — V/Q matching
A client with a pulmonary embolus develops sudden shortness
of breath and hypoxemia. Which physiological change best
explains the hypoxemia in pulmonary embolism?
A. Right-to-left intracardiac shunt
B. Decreased ventilation to an area with normal perfusion (low
V/Q)
C. Decreased perfusion to an area with normal ventilation (high
V/Q)
D. Decreased alveolar diffusion capacity in all alveoli
Correct: C. Decreased perfusion to an area with normal
ventilation (high V/Q)
Rationale — Correct: A pulmonary embolus blocks blood flow
to regions of the lung, causing ventilation without perfusion
(high ventilation/perfusion ratio, V/Q). This produces
physiologic dead space and impairs oxygen uptake systemically,
causing hypoxemia.
Rationale — Incorrect:
,A. A right-to-left intracardiac shunt bypasses pulmonary
oxygenation but is not caused by PE.
B. Decreased ventilation with normal perfusion (low V/Q)
occurs in airway obstruction or pneumonia, not PE.
D. Diffusion capacity may be affected in interstitial disease but
PE causes perfusion defects rather than global alveolar diffusion
impairment.
3) Renal — Acid-base and bicarbonate reabsorption
A client with chronic diarrhea develops metabolic acidosis.
Which renal compensation would the nurse expect?
A. Increased bicarbonate reabsorption in proximal tubules
B. Decreased ammonium (NH4+) excretion
C. Increased hydrogen ion secretion and increased NH4+
production
D. Increased filtered bicarbonate load
Correct: C. Increased hydrogen ion secretion and increased
NH4+ production
Rationale — Correct: In metabolic acidosis the kidney increases
H⁺ secretion in distal nephron and generates new bicarbonate—
partly via increased ammoniagenesis (NH4+ production) in
proximal tubules—thus increasing NH4+ excretion and
reclaiming bicarbonate to correct acidosis.
Rationale — Incorrect:
A. While bicarbonate reabsorption is important, in acidosis the
, kidney generates new bicarbonate rather than simply increasing
reabsorption alone.
B. The kidney increases, not decreases, ammonium excretion
during acidosis.
D. Filtered bicarbonate depends on plasma bicarbonate
concentration; acidosis lowers plasma bicarbonate, so filtered
load is not increased.
4) Endocrine — Thyroid hormone effects
A 36-year-old woman with hyperthyroidism reports
palpitations, heat intolerance, and weight loss. Which
mechanism best explains her tachycardia?
A. Increased vagal tone from thyroid hormone stimulation
B. Upregulation of β-adrenergic receptors and increased
sensitivity to catecholamines
C. Direct blockade of AV node conduction by thyroid hormone
D. Decreased myocardial oxygen demand
Correct: B. Upregulation of β-adrenergic receptors and
increased sensitivity to catecholamines
Rationale — Correct: Thyroid hormones increase expression of
β-adrenergic receptors and enhance sympathetic sensitivity,
leading to increased heart rate and contractility (tachycardia).
Rationale — Incorrect:
A. Vagal tone decreases heart rate; thyroid hormone increases
sympathetic responsiveness rather than vagal tone.
