WGU D236 Pathophysiology QUESTION Bank |
Complete Practice Test with Verified Answers &
Expert Rationales newest updated 2026/2027
QUESTION 1
What is the primary cellular consequence of ATP depletion resulting
from acute hypoxia?
• A. Failure of the Na+/K+ ATPase pump, leading to intracellular
accumulation of sodium and water (cellular swelling)
• B. Massive influx of extracellular potassium into the cytoplasm
• C. Uncontrolled replication of mitochondrial DNA
• D. Permanent activation of intracellular protein synthesis
Correct Answer: A. Failure of the Na+/K+ ATPase pump, leading to
intracellular accumulation of sodium and water (cellular swelling)
Detailed Rationale: Hypoxia halts oxidative phosphorylation, causing a
rapid drop in cellular ATP. Without ATP, the Na+/K+ ATPase membrane
pump fails, allowing sodium and water to rush into the cell, resulting in
acute cellular swelling and hydropic degeneration.
QUESTION 2
Which physiological response occurs in response to acute extracellular
fluid volume deficit (hypovolemia)?
• A. Secretion of atrial natriuretic peptide (ANP)
, • B. Activation of the renin-angiotensin-aldosterone system (RAAS)
and release of ADH
• C. Suppression of sympathetic nervous system activity
• D. Decreased reabsorption of sodium and water in the proximal
tubules
Correct Answer: B. Activation of the renin-angiotensin-aldosterone
system (RAAS) and release of ADH
Detailed Rationale: A drop in blood volume is sensed by renal
baroreceptors, triggering renin release. This activates the RAAS cascade
to retain sodium and water, while osmoreceptors stimulate ADH release
from the posterior pituitary to promote free water reabsorption and
restore blood volume.
QUESTION 3
What is the characteristic genetic transmission pattern of Marfan
syndrome?
• A. X-linked recessive
• B. Autosomal recessive
• C. Autosomal dominant
• D. Mitochondrial inheritance
Correct Answer: C. Autosomal dominant
Detailed Rationale: Marfan syndrome is caused by mutations in the
fibrillin-1 gene (𝐹𝐵𝑁1) and follows an autosomal dominant inheritance
pattern, meaning a single copy of the mutant gene from either parent is
enough to manifest the disorder.
,QUESTION 4
Which type of hypersensitivity reaction is mediated by T-lymphocytes
(cell-mediated) rather than antibodies, as seen in a positive tuberculin
skin test?
• A. Type I
• B. Type II
• C. Type III
• D. Type IV
Correct Answer: D. Type IV
Detailed Rationale: Type IV hypersensitivity is a delayed-type, cell-
mediated reaction. Instead of involving circulating antibodies, sensitized
T-lymphocytes react with antigens to release cytokines, recruiting
macrophages and causing localized inflammation (e.g., contact
dermatitis, TB skin tests).
QUESTION 5
A patient with chronic obstructive pulmonary disease (COPD) retains
carbon dioxide due to alveolar hypoventilation. Which primary acid-
base imbalance develops?
• A. Metabolic acidosis
• B. Metabolic alkalosis
• C. Respiratory acidosis
• D. Respiratory alkalosis
Correct Answer: C. Respiratory acidosis
, Detailed Rationale: Alveolar hypoventilation prevents the efficient
removal of carbon dioxide (CO2). As CO2 accumulates in the blood, it
combines with water to form carbonic acid, lowering blood pH and
causing respiratory acidosis.
QUESTION 6
What is the initial event in the pathogenesis of atherosclerosis?
• A. Formation of a calcified fibrous cap over the medial layer
• B. Endothelial injury and dysfunction caused by cardiovascular risk
factors
• C. Rupture of a deep vein thrombosis into the coronary bed
• D. Massive proliferation of osteoblasts within the arterial intima
Correct Answer: B. Endothelial injury and dysfunction caused by
cardiovascular risk factors
Detailed Rationale: Atherosclerosis begins with endothelial injury
caused by factors like hypertension, smoking, or hyperlipidemia. This
dysfunction increases permeability, allows monocytes and LDL
cholesterol to enter the arterial wall, and initiates the inflammatory
plaque cascade.
QUESTION 7
What is the primary pathophysiological mechanism of left-sided heart
failure leading to pulmonary congestion and dyspnea?
• A. Backflow of blood into the systemic venous circulation
• B. Inability of the left ventricle to eject blood effectively, causing a
backup of blood into the pulmonary veins and capillaries
Complete Practice Test with Verified Answers &
Expert Rationales newest updated 2026/2027
QUESTION 1
What is the primary cellular consequence of ATP depletion resulting
from acute hypoxia?
• A. Failure of the Na+/K+ ATPase pump, leading to intracellular
accumulation of sodium and water (cellular swelling)
• B. Massive influx of extracellular potassium into the cytoplasm
• C. Uncontrolled replication of mitochondrial DNA
• D. Permanent activation of intracellular protein synthesis
Correct Answer: A. Failure of the Na+/K+ ATPase pump, leading to
intracellular accumulation of sodium and water (cellular swelling)
Detailed Rationale: Hypoxia halts oxidative phosphorylation, causing a
rapid drop in cellular ATP. Without ATP, the Na+/K+ ATPase membrane
pump fails, allowing sodium and water to rush into the cell, resulting in
acute cellular swelling and hydropic degeneration.
QUESTION 2
Which physiological response occurs in response to acute extracellular
fluid volume deficit (hypovolemia)?
• A. Secretion of atrial natriuretic peptide (ANP)
, • B. Activation of the renin-angiotensin-aldosterone system (RAAS)
and release of ADH
• C. Suppression of sympathetic nervous system activity
• D. Decreased reabsorption of sodium and water in the proximal
tubules
Correct Answer: B. Activation of the renin-angiotensin-aldosterone
system (RAAS) and release of ADH
Detailed Rationale: A drop in blood volume is sensed by renal
baroreceptors, triggering renin release. This activates the RAAS cascade
to retain sodium and water, while osmoreceptors stimulate ADH release
from the posterior pituitary to promote free water reabsorption and
restore blood volume.
QUESTION 3
What is the characteristic genetic transmission pattern of Marfan
syndrome?
• A. X-linked recessive
• B. Autosomal recessive
• C. Autosomal dominant
• D. Mitochondrial inheritance
Correct Answer: C. Autosomal dominant
Detailed Rationale: Marfan syndrome is caused by mutations in the
fibrillin-1 gene (𝐹𝐵𝑁1) and follows an autosomal dominant inheritance
pattern, meaning a single copy of the mutant gene from either parent is
enough to manifest the disorder.
,QUESTION 4
Which type of hypersensitivity reaction is mediated by T-lymphocytes
(cell-mediated) rather than antibodies, as seen in a positive tuberculin
skin test?
• A. Type I
• B. Type II
• C. Type III
• D. Type IV
Correct Answer: D. Type IV
Detailed Rationale: Type IV hypersensitivity is a delayed-type, cell-
mediated reaction. Instead of involving circulating antibodies, sensitized
T-lymphocytes react with antigens to release cytokines, recruiting
macrophages and causing localized inflammation (e.g., contact
dermatitis, TB skin tests).
QUESTION 5
A patient with chronic obstructive pulmonary disease (COPD) retains
carbon dioxide due to alveolar hypoventilation. Which primary acid-
base imbalance develops?
• A. Metabolic acidosis
• B. Metabolic alkalosis
• C. Respiratory acidosis
• D. Respiratory alkalosis
Correct Answer: C. Respiratory acidosis
, Detailed Rationale: Alveolar hypoventilation prevents the efficient
removal of carbon dioxide (CO2). As CO2 accumulates in the blood, it
combines with water to form carbonic acid, lowering blood pH and
causing respiratory acidosis.
QUESTION 6
What is the initial event in the pathogenesis of atherosclerosis?
• A. Formation of a calcified fibrous cap over the medial layer
• B. Endothelial injury and dysfunction caused by cardiovascular risk
factors
• C. Rupture of a deep vein thrombosis into the coronary bed
• D. Massive proliferation of osteoblasts within the arterial intima
Correct Answer: B. Endothelial injury and dysfunction caused by
cardiovascular risk factors
Detailed Rationale: Atherosclerosis begins with endothelial injury
caused by factors like hypertension, smoking, or hyperlipidemia. This
dysfunction increases permeability, allows monocytes and LDL
cholesterol to enter the arterial wall, and initiates the inflammatory
plaque cascade.
QUESTION 7
What is the primary pathophysiological mechanism of left-sided heart
failure leading to pulmonary congestion and dyspnea?
• A. Backflow of blood into the systemic venous circulation
• B. Inability of the left ventricle to eject blood effectively, causing a
backup of blood into the pulmonary veins and capillaries
