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 perfusion
A postoperative client has a heart rate of 110 beats/min and a
blood pressure of 90/56 mm Hg. Which physiologic change
most directly explains the client's cool, clammy skin?
A. Increased cardiac contractility causing peripheral vasodilation
B. Reduced stroke volume leading to decreased cardiac output
and peripheral vasoconstriction
C. Failure of baroreceptor reflex resulting in peripheral pooling
of blood
D. Increased metabolic demand causing local skin vasodilation
Correct answer: B
Rationale:
• Correct (B): Cardiac output = HR × stroke volume. A
tachycardia with low BP suggests reduced stroke volume →
decreased cardiac output. The body compensates by
sympathetic activation, causing peripheral vasoconstriction
, to maintain central perfusion. Vasoconstriction reduces
skin blood flow → cool, clammy skin.
• A (incorrect): Increased contractility would usually
increase cardiac output and often improve skin perfusion;
it would not cause cool, clammy skin via vasodilation.
• C (incorrect): Baroreceptor failure typically causes unstable
BP but does not explain sympathetic-mediated cutaneous
vasoconstriction causing cool skin in the context of low BP.
• D (incorrect): Increased metabolic demand causes local
vasodilation (warm skin), not cool, clammy skin.
2 — Respiratory: V/Q mismatch and hypoxemia
A client with chronic bronchitis develops hypoxemia. Which
mechanism best describes why supplemental oxygen corrects
hypoxemia in most patients with chronic bronchitis?
A. Increases diffusion distance across alveolar membrane
B. Raises alveolar oxygen partial pressure to improve diffusion
into poorly ventilated alveoli
C. Lowers hemoglobin affinity for oxygen so more oxygen
unloads to tissues
D. Decreases ventilation–perfusion ratio globally to improve
matching
Correct answer: B
Rationale:
, • Correct (B): Supplemental oxygen increases the alveolar
partial pressure of oxygen (PAO₂), improving the diffusion
gradient from alveoli into pulmonary capillary blood —
especially important when alveoli are under-ventilated but
still have some ventilation.
• A (incorrect): Oxygen therapy does not increase diffusion
distance; increased diffusion distance would impair
oxygenation.
• C (incorrect): Lowering hemoglobin affinity (right shift)
promotes unloading to tissues but does not correct arterial
hypoxemia; oxygen therapy increases arterial oxygen
content by increasing PaO₂.
• D (incorrect): Oxygen administration does not centrally
decrease the V/Q ratio; it can improve oxygenation despite
V/Q mismatch but does not correct underlying mismatch.
3 — Renal: Glomerular filtration and lab findings
A patient with low renal perfusion has an elevated
BUN:creatinine ratio (>20:1). Which physiologic process
explains this ratio?
A. Increased glomerular filtration rate causing disproportionate
creatinine excretion
B. Reduced renal perfusion causing increased tubular
reabsorption of urea while creatinine remains filtered
C. Tubular necrosis causing increased creatinine reabsorption
, and decreased urea excretion
D. Hepatic failure causing decreased urea synthesis and lower
BUN
Correct answer: B
Rationale:
• Correct (B): In hypoperfusion (prerenal azotemia), the
kidney increases water and urea reabsorption to conserve
volume; creatinine is not reabsorbed, so BUN rises
disproportionately versus creatinine → high BUN:Cr ratio.
• A (incorrect): Increased GFR would lower both BUN and
creatinine, not raise BUN:Cr.
• C (incorrect): Acute tubular necrosis (intrinsic renal)
typically causes decreased reabsorption and a lower
BUN:Cr ratio (~10–15:1), not >20:1.
• D (incorrect): Hepatic failure lowers urea production,
leading to low BUN, not an elevated BUN:Cr ratio.
4 — Endocrine: Thyroid hormone and metabolism
A client reports heat intolerance, weight loss despite increased
appetite, and a bounding pulse. Which physiologic action of
excess thyroid hormone best explains these findings?
A. Decreased beta-adrenergic receptor expression causing
sympathetic hypoactivity
B. Increased basal metabolic rate via upregulation of Na⁺/K⁺-
Examination
9th Edition
• Author(s)Linda Anne Silvestri; Angela Silvestri
ANATOMY AND PHYSIOLOGY TEST BANK
1 — Cardiovascular: Cardiac output and perfusion
A postoperative client has a heart rate of 110 beats/min and a
blood pressure of 90/56 mm Hg. Which physiologic change
most directly explains the client's cool, clammy skin?
A. Increased cardiac contractility causing peripheral vasodilation
B. Reduced stroke volume leading to decreased cardiac output
and peripheral vasoconstriction
C. Failure of baroreceptor reflex resulting in peripheral pooling
of blood
D. Increased metabolic demand causing local skin vasodilation
Correct answer: B
Rationale:
• Correct (B): Cardiac output = HR × stroke volume. A
tachycardia with low BP suggests reduced stroke volume →
decreased cardiac output. The body compensates by
sympathetic activation, causing peripheral vasoconstriction
, to maintain central perfusion. Vasoconstriction reduces
skin blood flow → cool, clammy skin.
• A (incorrect): Increased contractility would usually
increase cardiac output and often improve skin perfusion;
it would not cause cool, clammy skin via vasodilation.
• C (incorrect): Baroreceptor failure typically causes unstable
BP but does not explain sympathetic-mediated cutaneous
vasoconstriction causing cool skin in the context of low BP.
• D (incorrect): Increased metabolic demand causes local
vasodilation (warm skin), not cool, clammy skin.
2 — Respiratory: V/Q mismatch and hypoxemia
A client with chronic bronchitis develops hypoxemia. Which
mechanism best describes why supplemental oxygen corrects
hypoxemia in most patients with chronic bronchitis?
A. Increases diffusion distance across alveolar membrane
B. Raises alveolar oxygen partial pressure to improve diffusion
into poorly ventilated alveoli
C. Lowers hemoglobin affinity for oxygen so more oxygen
unloads to tissues
D. Decreases ventilation–perfusion ratio globally to improve
matching
Correct answer: B
Rationale:
, • Correct (B): Supplemental oxygen increases the alveolar
partial pressure of oxygen (PAO₂), improving the diffusion
gradient from alveoli into pulmonary capillary blood —
especially important when alveoli are under-ventilated but
still have some ventilation.
• A (incorrect): Oxygen therapy does not increase diffusion
distance; increased diffusion distance would impair
oxygenation.
• C (incorrect): Lowering hemoglobin affinity (right shift)
promotes unloading to tissues but does not correct arterial
hypoxemia; oxygen therapy increases arterial oxygen
content by increasing PaO₂.
• D (incorrect): Oxygen administration does not centrally
decrease the V/Q ratio; it can improve oxygenation despite
V/Q mismatch but does not correct underlying mismatch.
3 — Renal: Glomerular filtration and lab findings
A patient with low renal perfusion has an elevated
BUN:creatinine ratio (>20:1). Which physiologic process
explains this ratio?
A. Increased glomerular filtration rate causing disproportionate
creatinine excretion
B. Reduced renal perfusion causing increased tubular
reabsorption of urea while creatinine remains filtered
C. Tubular necrosis causing increased creatinine reabsorption
, and decreased urea excretion
D. Hepatic failure causing decreased urea synthesis and lower
BUN
Correct answer: B
Rationale:
• Correct (B): In hypoperfusion (prerenal azotemia), the
kidney increases water and urea reabsorption to conserve
volume; creatinine is not reabsorbed, so BUN rises
disproportionately versus creatinine → high BUN:Cr ratio.
• A (incorrect): Increased GFR would lower both BUN and
creatinine, not raise BUN:Cr.
• C (incorrect): Acute tubular necrosis (intrinsic renal)
typically causes decreased reabsorption and a lower
BUN:Cr ratio (~10–15:1), not >20:1.
• D (incorrect): Hepatic failure lowers urea production,
leading to low BUN, not an elevated BUN:Cr ratio.
4 — Endocrine: Thyroid hormone and metabolism
A client reports heat intolerance, weight loss despite increased
appetite, and a bounding pulse. Which physiologic action of
excess thyroid hormone best explains these findings?
A. Decreased beta-adrenergic receptor expression causing
sympathetic hypoactivity
B. Increased basal metabolic rate via upregulation of Na⁺/K⁺-
