WGU D236 Pathophysiology | Western Governors
University D236 Study Guide & Objective Assessment
Exam Prep 2026/2027 | Pathophysiology OA Review,
Disease Processes, Cellular Injury & Adaptation,
Inflammation, Immunity, Fluid & Electrolyte Balance,
Acid-Base Disorders, Cardiovascular, Respiratory, Renal,
Neurological, Endocrine, GI, Genetic & Multisystem
Conditions, Practice Questions, Answers & Detailed
Rationales
Question 1: A patient with a history of chronic hypertension develops left
ventricular hypertrophy. Which of the following best describes this cellular
adaptation?
A. An increase in the number of cells in the heart muscle
B. A decrease in the size of individual heart muscle cells
C. An increase in the size of individual heart muscle cells
D. A replacement of heart muscle cells with another cell type
CORRECT ANSWER: C. An increase in the size of individual heart muscle cells
Rationale: Hypertrophy is an increase in the size of individual cells, not an increase in
their number. In response to the increased workload from chronic hypertension, cardiac
muscle cells (which have limited mitotic capacity) undergo hypertrophy to compensate.
This is an adaptive mechanism to maintain cardiac output against increased afterload .
Question 2: A 65-year-old patient with a long history of smoking presents with
a chronic cough and shortness of breath. Pathological analysis reveals
destruction of alveolar walls and permanent enlargement of air spaces. Which
condition is most consistent with these findings?
A. Chronic bronchitis
B. Emphysema
C. Asthma
D. Pulmonary fibrosis
CORRECT ANSWER: B. Emphysema
Rationale: Emphysema, a component of COPD, is characterized by the destruction of
alveolar walls and permanent enlargement of the air spaces distal to the terminal
bronchioles. This leads to decreased elastic recoil and airflow limitation. Chronic
bronchitis is defined by a chronic productive cough, asthma by reversible airway
obstruction, and fibrosis by scarring and stiffening of the lung tissue .
Question 3: During a severe asthma attack, a patient's arterial blood gas shows
a pH of 7.28, PaCO2 of 55 mmHg, and HCO3- of 24 mEq/L. Which acid-base
disorder is present?
A. Metabolic acidosis
B. Metabolic alkalosis
,C. Respiratory acidosis
D. Respiratory alkalosis
CORRECT ANSWER: C. Respiratory acidosis
Rationale: The low pH (7.28) indicates acidosis. The elevated PaCO2 (55 mmHg) is
above the normal range (35-45 mmHg), indicating a primary respiratory problem that is
causing carbon dioxide retention. The HCO3- is normal, suggesting this is an acute
process without renal compensation. This combination is classic for acute respiratory
acidosis due to hypoventilation .
Question 4: A patient is diagnosed with pernicious anemia, which is caused by
a deficiency in intrinsic factor. What is the primary pathophysiological
consequence of this deficiency?
A. Impaired iron absorption in the duodenum
B. Impaired absorption of vitamin B12 in the ileum
C. Impaired folate metabolism
D. Increased destruction of red blood cells in the spleen
CORRECT ANSWER: B. Impaired absorption of vitamin B12 in the ileum
Rationale: Intrinsic factor, produced by gastric parietal cells, is essential for the
absorption of vitamin B12 in the terminal ileum. A deficiency in intrinsic factor (often
due to autoimmune destruction of parietal cells) leads to vitamin B12 deficiency. This
impairs DNA synthesis in rapidly dividing cells, most notably in the bone marrow,
leading to megaloblastic anemia .
Question 5: In a patient with a genetic condition causing a defect in the CFTR
protein, which physiological process is primarily disrupted?
A. Active transport of sodium and potassium across cell membranes
B. Chloride ion transport across epithelial cells
C. Production of surfactant in the alveoli
D. Secretion of insulin from pancreatic beta cells
CORRECT ANSWER: B. Chloride ion transport across epithelial cells
Rationale: The CFTR protein functions as a chloride channel on the apical surface of
epithelial cells. A defect leads to impaired chloride transport, which in turn affects water
and sodium movement across cell surfaces. This results in the production of thick,
dehydrated mucus in organs like the lungs and pancreas, leading to the clinical
manifestations of cystic fibrosis .
Question 6: A patient is diagnosed with an aggressive tumor that has cells
showing a high degree of pleomorphism and numerous mitotic figures. This is
characteristic of which of the following?
A. A benign tumor
B. A well-differentiated tumor
,C. A poorly differentiated, malignant tumor
D. A tumor of epithelial origin
CORRECT ANSWER: C. A poorly differentiated, malignant tumor
Rationale: Pleomorphism (variation in cell size and shape) and a high number of mitotic
figures are key indicators of malignancy and poor differentiation. Malignant cells often
have large, hyperchromatic nuclei and an increased nuclear-to-cytoplasmic ratio. Benign
tumors are typically well-differentiated and have few mitotic figures .
Question 7: A patient presents with fever, fatigue, and a new heart murmur.
Echocardiography reveals vegetations on the mitral valve. Which of the
following is the most likely diagnosis?
A. Pericarditis
B. Myocarditis
C. Infective endocarditis
D. Mitral valve stenosis
CORRECT ANSWER: C. Infective endocarditis
Rationale: Infective endocarditis is an infection of the endocardial surface of the heart,
most commonly the heart valves. The clinical presentation includes fever, fatigue, and a
new or changing heart murmur. The hallmark finding on echocardiography is the
presence of vegetations on the valves .
Question 8: A child is brought to the clinic with a bright red rash on the
cheeks, giving a "slapped cheek" appearance. The child had a mild fever and
upper respiratory symptoms a few days prior. Which condition is most likely?
A. Measles
B. Scarlet fever
C. Erythema infectiosum (Fifth disease)
D. Rubella
CORRECT ANSWER: C. Erythema infectiosum (Fifth disease)
Rationale: Erythema infectiosum, caused by Parvovirus B19, is characterized by a
distinct "slapped cheek" rash on the face. This is usually preceded by a mild, nonspecific
febrile illness. The rash may then spread to the trunk and extremities in a lacy pattern .
Question 9: A patient with chronic kidney disease develops hyperkalemia.
What is the primary mechanism by which the kidneys normally excrete excess
potassium?
A. Filtration of potassium at the glomerulus
B. Secretion of potassium into the distal convoluted tubule
C. Reabsorption of potassium in the proximal convoluted tubule
D. Active transport of potassium into the loop of Henle
, CORRECT ANSWER: B. Secretion of potassium into the distal convoluted
tubule
Rationale: While potassium is freely filtered at the glomerulus, the primary mechanism
for regulating potassium excretion is its active secretion into the distal convoluted tubule
and collecting duct. This process is controlled by aldosterone. In kidney disease, this
function is impaired, leading to potassium retention and hyperkalemia .
Question 10: A patient with a history of hyperthyroidism is being treated with
radioactive iodine. What is the most likely mechanism by which this treatment
controls the disease?
A. Stimulates the production of thyroid-stimulating hormone (TSH)
B. Blocks the synthesis of thyroid hormones
C. Destroys the overactive thyroid follicular cells
D. Prevents the release of preformed thyroid hormones
CORRECT ANSWER: C. Destroys the overactive thyroid follicular cells
Rationale: Radioactive iodine is selectively taken up by the overactive thyroid follicular
cells. The radiation emitted destroys these cells, thereby reducing the overall production
of thyroid hormones. This is a common definitive treatment for Graves' disease and
other forms of hyperthyroidism .
Question 11: Which of the following is a classic clinical manifestation of
hypocalcemia?
A. Positive Chvostek's sign and Trousseau's sign
B. Muscle weakness and constipation
C. Polyuria and polydipsia
D. Hypertension and tachycardia
CORRECT ANSWER: A. Positive Chvostek's sign and Trousseau's sign
Rationale: Hypocalcemia (low serum calcium) increases the excitability of
neuromuscular junctions. This leads to characteristic signs such as Chvostek's sign
(facial twitching upon tapping the facial nerve) and Trousseau's sign (carpal spasm
induced by inflating a blood pressure cuff on the arm) .
Question 12: A patient with a confirmed diagnosis of Systemic Lupus
Erythematosus (SLE) presents with joint pain and swelling. What is the
underlying pathology of this autoimmune disease?
A. Antibodies attacking the myelin sheath of nerves
B. Production of autoantibodies against nuclear antigens
C. Immune-mediated destruction of pancreatic beta cells
D. Antibodies targeting the acetylcholine receptor at the neuromuscular junction
CORRECT ANSWER: B. Production of autoantibodies against nuclear antigens
University D236 Study Guide & Objective Assessment
Exam Prep 2026/2027 | Pathophysiology OA Review,
Disease Processes, Cellular Injury & Adaptation,
Inflammation, Immunity, Fluid & Electrolyte Balance,
Acid-Base Disorders, Cardiovascular, Respiratory, Renal,
Neurological, Endocrine, GI, Genetic & Multisystem
Conditions, Practice Questions, Answers & Detailed
Rationales
Question 1: A patient with a history of chronic hypertension develops left
ventricular hypertrophy. Which of the following best describes this cellular
adaptation?
A. An increase in the number of cells in the heart muscle
B. A decrease in the size of individual heart muscle cells
C. An increase in the size of individual heart muscle cells
D. A replacement of heart muscle cells with another cell type
CORRECT ANSWER: C. An increase in the size of individual heart muscle cells
Rationale: Hypertrophy is an increase in the size of individual cells, not an increase in
their number. In response to the increased workload from chronic hypertension, cardiac
muscle cells (which have limited mitotic capacity) undergo hypertrophy to compensate.
This is an adaptive mechanism to maintain cardiac output against increased afterload .
Question 2: A 65-year-old patient with a long history of smoking presents with
a chronic cough and shortness of breath. Pathological analysis reveals
destruction of alveolar walls and permanent enlargement of air spaces. Which
condition is most consistent with these findings?
A. Chronic bronchitis
B. Emphysema
C. Asthma
D. Pulmonary fibrosis
CORRECT ANSWER: B. Emphysema
Rationale: Emphysema, a component of COPD, is characterized by the destruction of
alveolar walls and permanent enlargement of the air spaces distal to the terminal
bronchioles. This leads to decreased elastic recoil and airflow limitation. Chronic
bronchitis is defined by a chronic productive cough, asthma by reversible airway
obstruction, and fibrosis by scarring and stiffening of the lung tissue .
Question 3: During a severe asthma attack, a patient's arterial blood gas shows
a pH of 7.28, PaCO2 of 55 mmHg, and HCO3- of 24 mEq/L. Which acid-base
disorder is present?
A. Metabolic acidosis
B. Metabolic alkalosis
,C. Respiratory acidosis
D. Respiratory alkalosis
CORRECT ANSWER: C. Respiratory acidosis
Rationale: The low pH (7.28) indicates acidosis. The elevated PaCO2 (55 mmHg) is
above the normal range (35-45 mmHg), indicating a primary respiratory problem that is
causing carbon dioxide retention. The HCO3- is normal, suggesting this is an acute
process without renal compensation. This combination is classic for acute respiratory
acidosis due to hypoventilation .
Question 4: A patient is diagnosed with pernicious anemia, which is caused by
a deficiency in intrinsic factor. What is the primary pathophysiological
consequence of this deficiency?
A. Impaired iron absorption in the duodenum
B. Impaired absorption of vitamin B12 in the ileum
C. Impaired folate metabolism
D. Increased destruction of red blood cells in the spleen
CORRECT ANSWER: B. Impaired absorption of vitamin B12 in the ileum
Rationale: Intrinsic factor, produced by gastric parietal cells, is essential for the
absorption of vitamin B12 in the terminal ileum. A deficiency in intrinsic factor (often
due to autoimmune destruction of parietal cells) leads to vitamin B12 deficiency. This
impairs DNA synthesis in rapidly dividing cells, most notably in the bone marrow,
leading to megaloblastic anemia .
Question 5: In a patient with a genetic condition causing a defect in the CFTR
protein, which physiological process is primarily disrupted?
A. Active transport of sodium and potassium across cell membranes
B. Chloride ion transport across epithelial cells
C. Production of surfactant in the alveoli
D. Secretion of insulin from pancreatic beta cells
CORRECT ANSWER: B. Chloride ion transport across epithelial cells
Rationale: The CFTR protein functions as a chloride channel on the apical surface of
epithelial cells. A defect leads to impaired chloride transport, which in turn affects water
and sodium movement across cell surfaces. This results in the production of thick,
dehydrated mucus in organs like the lungs and pancreas, leading to the clinical
manifestations of cystic fibrosis .
Question 6: A patient is diagnosed with an aggressive tumor that has cells
showing a high degree of pleomorphism and numerous mitotic figures. This is
characteristic of which of the following?
A. A benign tumor
B. A well-differentiated tumor
,C. A poorly differentiated, malignant tumor
D. A tumor of epithelial origin
CORRECT ANSWER: C. A poorly differentiated, malignant tumor
Rationale: Pleomorphism (variation in cell size and shape) and a high number of mitotic
figures are key indicators of malignancy and poor differentiation. Malignant cells often
have large, hyperchromatic nuclei and an increased nuclear-to-cytoplasmic ratio. Benign
tumors are typically well-differentiated and have few mitotic figures .
Question 7: A patient presents with fever, fatigue, and a new heart murmur.
Echocardiography reveals vegetations on the mitral valve. Which of the
following is the most likely diagnosis?
A. Pericarditis
B. Myocarditis
C. Infective endocarditis
D. Mitral valve stenosis
CORRECT ANSWER: C. Infective endocarditis
Rationale: Infective endocarditis is an infection of the endocardial surface of the heart,
most commonly the heart valves. The clinical presentation includes fever, fatigue, and a
new or changing heart murmur. The hallmark finding on echocardiography is the
presence of vegetations on the valves .
Question 8: A child is brought to the clinic with a bright red rash on the
cheeks, giving a "slapped cheek" appearance. The child had a mild fever and
upper respiratory symptoms a few days prior. Which condition is most likely?
A. Measles
B. Scarlet fever
C. Erythema infectiosum (Fifth disease)
D. Rubella
CORRECT ANSWER: C. Erythema infectiosum (Fifth disease)
Rationale: Erythema infectiosum, caused by Parvovirus B19, is characterized by a
distinct "slapped cheek" rash on the face. This is usually preceded by a mild, nonspecific
febrile illness. The rash may then spread to the trunk and extremities in a lacy pattern .
Question 9: A patient with chronic kidney disease develops hyperkalemia.
What is the primary mechanism by which the kidneys normally excrete excess
potassium?
A. Filtration of potassium at the glomerulus
B. Secretion of potassium into the distal convoluted tubule
C. Reabsorption of potassium in the proximal convoluted tubule
D. Active transport of potassium into the loop of Henle
, CORRECT ANSWER: B. Secretion of potassium into the distal convoluted
tubule
Rationale: While potassium is freely filtered at the glomerulus, the primary mechanism
for regulating potassium excretion is its active secretion into the distal convoluted tubule
and collecting duct. This process is controlled by aldosterone. In kidney disease, this
function is impaired, leading to potassium retention and hyperkalemia .
Question 10: A patient with a history of hyperthyroidism is being treated with
radioactive iodine. What is the most likely mechanism by which this treatment
controls the disease?
A. Stimulates the production of thyroid-stimulating hormone (TSH)
B. Blocks the synthesis of thyroid hormones
C. Destroys the overactive thyroid follicular cells
D. Prevents the release of preformed thyroid hormones
CORRECT ANSWER: C. Destroys the overactive thyroid follicular cells
Rationale: Radioactive iodine is selectively taken up by the overactive thyroid follicular
cells. The radiation emitted destroys these cells, thereby reducing the overall production
of thyroid hormones. This is a common definitive treatment for Graves' disease and
other forms of hyperthyroidism .
Question 11: Which of the following is a classic clinical manifestation of
hypocalcemia?
A. Positive Chvostek's sign and Trousseau's sign
B. Muscle weakness and constipation
C. Polyuria and polydipsia
D. Hypertension and tachycardia
CORRECT ANSWER: A. Positive Chvostek's sign and Trousseau's sign
Rationale: Hypocalcemia (low serum calcium) increases the excitability of
neuromuscular junctions. This leads to characteristic signs such as Chvostek's sign
(facial twitching upon tapping the facial nerve) and Trousseau's sign (carpal spasm
induced by inflating a blood pressure cuff on the arm) .
Question 12: A patient with a confirmed diagnosis of Systemic Lupus
Erythematosus (SLE) presents with joint pain and swelling. What is the
underlying pathology of this autoimmune disease?
A. Antibodies attacking the myelin sheath of nerves
B. Production of autoantibodies against nuclear antigens
C. Immune-mediated destruction of pancreatic beta cells
D. Antibodies targeting the acetylcholine receptor at the neuromuscular junction
CORRECT ANSWER: B. Production of autoantibodies against nuclear antigens
