NURS 231 Pathophysiology | Portage Learning /
Geneva College 2026/2027 Study Guide, Exam Prep,
Practice Questions & Answers, Detailed Rationales,
Module 1–10 Review, Cellular Adaptation,
Inflammation, Immunity, Fluid & Electrolyte
Balance, Cardiovascular, Respiratory, Neurological,
Renal, GI and Endocrine Disorders
Question 1: A 65-year-old male with a history of chronic obstructive
pulmonary disease (COPD) presents with worsening dyspnea and peripheral
edema. An arterial blood gas (ABG) reveals a pH of 7.32, PaCO2 of 68 mmHg,
and HCO3- of 36 mEq/L. Which of the following best describes his acid-base
status?
A. Acute respiratory acidosis without metabolic compensation
B. Chronic respiratory acidosis with metabolic compensation
C. Acute respiratory alkalosis with metabolic compensation
D. Chronic metabolic acidosis with respiratory compensation
CORRECT ANSWER: B. Chronic respiratory acidosis with metabolic
compensation
Rationale: The ABG shows a low pH (acidemia) and an elevated PaCO2, indicating a
respiratory acidosis. The elevated bicarbonate (HCO3-) suggests a metabolic
compensatory response. Because the bicarbonate is significantly elevated, this indicates
a chronic process where the kidneys have had time to retain bicarbonate to compensate
for the chronic hypercapnia.
Question 2: A patient with type 1 diabetes mellitus is found unconscious.
Laboratory results show a blood glucose of 650 mg/dL, arterial pH of 7.15, and
serum ketones are positive. Which of the following is the primary
pathophysiological mechanism responsible for this patient's acid-base
disturbance?
A. Increased renal excretion of bicarbonate
B. Excessive production of lactic acid due to tissue hypoxia
C. Increased production of ketoacids due to fatty acid metabolism
D. Impaired alveolar ventilation leading to CO2 retention
CORRECT ANSWER: C. Increased production of ketoacids due to fatty acid
metabolism
Rationale: In type 1 diabetes with insufficient insulin, the body cannot utilize glucose for
energy and shifts to fat metabolism. This leads to the overproduction of ketoacids
(acetoacetic acid and beta-hydroxybutyric acid), overwhelming the body's buffering
system and causing an anion gap metabolic acidosis.
Question 3: A patient is admitted with severe diarrhea for three days.
Laboratory findings reveal a serum sodium of 131 mEq/L, potassium of 2.9
,mEq/L, and chloride of 118 mEq/L. An ABG shows a pH of 7.25 and HCO3- of
15 mEq/L. Which of the following acid-base imbalances is most likely?
A. Respiratory acidosis
B. Metabolic alkalosis
C. Respiratory alkalosis
D. Metabolic acidosis
CORRECT ANSWER: D. Metabolic acidosis
Rationale: Severe diarrhea results in the loss of bicarbonate-rich intestinal fluids, leading
to a normal anion gap (hyperchloremic) metabolic acidosis. The loss of bicarbonate
directly lowers the serum HCO3- level and decreases the pH. The elevated chloride is a
compensatory response to maintain electrical neutrality as bicarbonate is lost.
Question 4: A 56-year-old female with anxiety is hyperventilating. Her ABG
results are pH 7.52, PaCO2 28 mmHg, and HCO3- 24 mEq/L. Which of the
following is the primary mechanism causing her alkalemia?
A. Increased metabolic production of bicarbonate
B. Decreased renal excretion of hydrogen ions
C. Excessive loss of CO2 via the lungs
D. Severe vomiting with loss of gastric acid
CORRECT ANSWER: C. Excessive loss of CO2 via the lungs
Rationale: Hyperventilation causes a rapid loss of CO2 from the lungs. This decreases
the PaCO2, which shifts the carbonic acid-bicarbonate equilibrium to the left, leading to
a decrease in hydrogen ion concentration and a subsequent rise in pH, resulting in
respiratory alkalosis.
Question 5: A patient with renal failure has the following lab values: pH 7.20,
PaCO2 30 mmHg, HCO3- 12 mEq/L. Which of the following best describes this
patient's acid-base condition?
A. Metabolic acidosis with partial respiratory compensation
B. Respiratory acidosis with metabolic compensation
C. Metabolic alkalosis with respiratory compensation
D. Respiratory alkalosis with metabolic compensation
CORRECT ANSWER: A. Metabolic acidosis with partial respiratory
compensation
Rationale: The primary disturbance is metabolic acidosis (low pH and low HCO3-). The
PaCO2 is also low, indicating the respiratory system is attempting to compensate by
blowing off CO2. However, the pH is still below 7.35, meaning the compensation is
partial and the primary acid-base disturbance persists.
Question 6: A patient with a history of COPD is placed on supplemental
oxygen. Following this, he becomes lethargic and confused. Which of the
,following pathophysiological mechanisms best explains this change in mental
status?
A. Oxygen-induced hyperventilation leading to respiratory alkalosis
B. Loss of the hypoxic drive to breathe, leading to CO2 narcosis
C. A sudden drop in hemoglobin oxygen saturation
D. Development of acute metabolic alkalosis due to bicarbonate retention
CORRECT ANSWER: B. Loss of the hypoxic drive to breathe, leading to CO2
narcosis
Rationale: In chronic COPD, the respiratory center becomes insensitive to high CO2
levels and relies on hypoxemia to stimulate breathing. Administering high-flow oxygen
removes this hypoxic stimulus, resulting in hypoventilation. This causes a further rise in
PaCO2 (hypercapnia), which leads to CO2 narcosis, characterized by lethargy, confusion,
and potentially coma.
Question 7: A patient is diagnosed with a condition characterized by the
destruction of the alveolar walls, leading to large, permanently inflated air
spaces. Which of the following is the most likely underlying disease process?
A. Chronic bronchitis
B. Emphysema
C. Asthma
D. Pulmonary fibrosis
CORRECT ANSWER: B. Emphysema
Rationale: Emphysema is pathologically defined by the permanent enlargement of air
spaces distal to the terminal bronchioles, accompanied by the destruction of alveolar
walls without significant fibrosis. This leads to a loss of elastic recoil and a decrease in
the surface area for gas exchange.
Question 8: A 7-year-old child presents with a barking cough, inspiratory
stridor, and hoarseness. These symptoms are most characteristic of which of
the following upper airway infections?
A. Epiglottitis
B. Laryngotracheobronchitis (Croup)
C. Bacterial tracheitis
D. Acute pharyngitis
CORRECT ANSWER: B. Laryngotracheobronchitis (Croup)
Rationale: Croup, or laryngotracheobronchitis, is a viral infection causing inflammation
and edema of the larynx, trachea, and bronchi. This subglottic swelling produces the
classic "barking" cough, inspiratory stridor, and hoarseness, most commonly seen in
children.
, Question 9: A patient with a pulmonary embolism presents with acute onset of
tachypnea, chest pain, and hypoxia. The ventilation-perfusion (V/Q)
mismatch in this condition is primarily due to which of the following?
A. Decreased ventilation with normal perfusion
B. Normal ventilation with decreased perfusion
C. Decreased ventilation and decreased perfusion
D. Increased ventilation with increased perfusion
CORRECT ANSWER: B. Normal ventilation with decreased perfusion
Rationale: A pulmonary embolism is a blockage of a pulmonary artery by a thrombus.
This obstructs blood flow to a segment of the lung. Alveoli in this area continue to be
ventilated but are not perfused, creating a high V/Q ratio (dead space) and leading to
significant hypoxemia.
Question 10: A patient with a history of asthma is experiencing an acute
exacerbation. Auscultation of the lungs reveals absent breath sounds in the left
lower lobe. This finding is most likely indicative of which of the following
complications?
A. Pneumothorax
B. Atelectasis
C. Pleural effusion
D. Mucus plugging
CORRECT ANSWER: D. Mucus plugging
Rationale: In an acute asthma exacerbation, inflammation leads to bronchospasm,
mucosal edema, and increased mucus production. A thick mucus plug can completely
obstruct a bronchus, preventing airflow and leading to absent breath sounds over the
affected area.
Question 11: A patient with heart failure develops pulmonary edema. The
underlying mechanism for the fluid accumulation in the lungs is best described
as:
A. Decreased capillary hydrostatic pressure
B. Increased capillary hydrostatic pressure
C. Decreased capillary oncotic pressure
D. Increased capillary permeability
CORRECT ANSWER: B. Increased capillary hydrostatic pressure
Rationale: Left-sided heart failure results in increased pressure in the pulmonary veins
and capillaries. This elevated hydrostatic pressure forces fluid out of the pulmonary
capillaries and into the interstitial space and alveoli, resulting in pulmonary edema.
Geneva College 2026/2027 Study Guide, Exam Prep,
Practice Questions & Answers, Detailed Rationales,
Module 1–10 Review, Cellular Adaptation,
Inflammation, Immunity, Fluid & Electrolyte
Balance, Cardiovascular, Respiratory, Neurological,
Renal, GI and Endocrine Disorders
Question 1: A 65-year-old male with a history of chronic obstructive
pulmonary disease (COPD) presents with worsening dyspnea and peripheral
edema. An arterial blood gas (ABG) reveals a pH of 7.32, PaCO2 of 68 mmHg,
and HCO3- of 36 mEq/L. Which of the following best describes his acid-base
status?
A. Acute respiratory acidosis without metabolic compensation
B. Chronic respiratory acidosis with metabolic compensation
C. Acute respiratory alkalosis with metabolic compensation
D. Chronic metabolic acidosis with respiratory compensation
CORRECT ANSWER: B. Chronic respiratory acidosis with metabolic
compensation
Rationale: The ABG shows a low pH (acidemia) and an elevated PaCO2, indicating a
respiratory acidosis. The elevated bicarbonate (HCO3-) suggests a metabolic
compensatory response. Because the bicarbonate is significantly elevated, this indicates
a chronic process where the kidneys have had time to retain bicarbonate to compensate
for the chronic hypercapnia.
Question 2: A patient with type 1 diabetes mellitus is found unconscious.
Laboratory results show a blood glucose of 650 mg/dL, arterial pH of 7.15, and
serum ketones are positive. Which of the following is the primary
pathophysiological mechanism responsible for this patient's acid-base
disturbance?
A. Increased renal excretion of bicarbonate
B. Excessive production of lactic acid due to tissue hypoxia
C. Increased production of ketoacids due to fatty acid metabolism
D. Impaired alveolar ventilation leading to CO2 retention
CORRECT ANSWER: C. Increased production of ketoacids due to fatty acid
metabolism
Rationale: In type 1 diabetes with insufficient insulin, the body cannot utilize glucose for
energy and shifts to fat metabolism. This leads to the overproduction of ketoacids
(acetoacetic acid and beta-hydroxybutyric acid), overwhelming the body's buffering
system and causing an anion gap metabolic acidosis.
Question 3: A patient is admitted with severe diarrhea for three days.
Laboratory findings reveal a serum sodium of 131 mEq/L, potassium of 2.9
,mEq/L, and chloride of 118 mEq/L. An ABG shows a pH of 7.25 and HCO3- of
15 mEq/L. Which of the following acid-base imbalances is most likely?
A. Respiratory acidosis
B. Metabolic alkalosis
C. Respiratory alkalosis
D. Metabolic acidosis
CORRECT ANSWER: D. Metabolic acidosis
Rationale: Severe diarrhea results in the loss of bicarbonate-rich intestinal fluids, leading
to a normal anion gap (hyperchloremic) metabolic acidosis. The loss of bicarbonate
directly lowers the serum HCO3- level and decreases the pH. The elevated chloride is a
compensatory response to maintain electrical neutrality as bicarbonate is lost.
Question 4: A 56-year-old female with anxiety is hyperventilating. Her ABG
results are pH 7.52, PaCO2 28 mmHg, and HCO3- 24 mEq/L. Which of the
following is the primary mechanism causing her alkalemia?
A. Increased metabolic production of bicarbonate
B. Decreased renal excretion of hydrogen ions
C. Excessive loss of CO2 via the lungs
D. Severe vomiting with loss of gastric acid
CORRECT ANSWER: C. Excessive loss of CO2 via the lungs
Rationale: Hyperventilation causes a rapid loss of CO2 from the lungs. This decreases
the PaCO2, which shifts the carbonic acid-bicarbonate equilibrium to the left, leading to
a decrease in hydrogen ion concentration and a subsequent rise in pH, resulting in
respiratory alkalosis.
Question 5: A patient with renal failure has the following lab values: pH 7.20,
PaCO2 30 mmHg, HCO3- 12 mEq/L. Which of the following best describes this
patient's acid-base condition?
A. Metabolic acidosis with partial respiratory compensation
B. Respiratory acidosis with metabolic compensation
C. Metabolic alkalosis with respiratory compensation
D. Respiratory alkalosis with metabolic compensation
CORRECT ANSWER: A. Metabolic acidosis with partial respiratory
compensation
Rationale: The primary disturbance is metabolic acidosis (low pH and low HCO3-). The
PaCO2 is also low, indicating the respiratory system is attempting to compensate by
blowing off CO2. However, the pH is still below 7.35, meaning the compensation is
partial and the primary acid-base disturbance persists.
Question 6: A patient with a history of COPD is placed on supplemental
oxygen. Following this, he becomes lethargic and confused. Which of the
,following pathophysiological mechanisms best explains this change in mental
status?
A. Oxygen-induced hyperventilation leading to respiratory alkalosis
B. Loss of the hypoxic drive to breathe, leading to CO2 narcosis
C. A sudden drop in hemoglobin oxygen saturation
D. Development of acute metabolic alkalosis due to bicarbonate retention
CORRECT ANSWER: B. Loss of the hypoxic drive to breathe, leading to CO2
narcosis
Rationale: In chronic COPD, the respiratory center becomes insensitive to high CO2
levels and relies on hypoxemia to stimulate breathing. Administering high-flow oxygen
removes this hypoxic stimulus, resulting in hypoventilation. This causes a further rise in
PaCO2 (hypercapnia), which leads to CO2 narcosis, characterized by lethargy, confusion,
and potentially coma.
Question 7: A patient is diagnosed with a condition characterized by the
destruction of the alveolar walls, leading to large, permanently inflated air
spaces. Which of the following is the most likely underlying disease process?
A. Chronic bronchitis
B. Emphysema
C. Asthma
D. Pulmonary fibrosis
CORRECT ANSWER: B. Emphysema
Rationale: Emphysema is pathologically defined by the permanent enlargement of air
spaces distal to the terminal bronchioles, accompanied by the destruction of alveolar
walls without significant fibrosis. This leads to a loss of elastic recoil and a decrease in
the surface area for gas exchange.
Question 8: A 7-year-old child presents with a barking cough, inspiratory
stridor, and hoarseness. These symptoms are most characteristic of which of
the following upper airway infections?
A. Epiglottitis
B. Laryngotracheobronchitis (Croup)
C. Bacterial tracheitis
D. Acute pharyngitis
CORRECT ANSWER: B. Laryngotracheobronchitis (Croup)
Rationale: Croup, or laryngotracheobronchitis, is a viral infection causing inflammation
and edema of the larynx, trachea, and bronchi. This subglottic swelling produces the
classic "barking" cough, inspiratory stridor, and hoarseness, most commonly seen in
children.
, Question 9: A patient with a pulmonary embolism presents with acute onset of
tachypnea, chest pain, and hypoxia. The ventilation-perfusion (V/Q)
mismatch in this condition is primarily due to which of the following?
A. Decreased ventilation with normal perfusion
B. Normal ventilation with decreased perfusion
C. Decreased ventilation and decreased perfusion
D. Increased ventilation with increased perfusion
CORRECT ANSWER: B. Normal ventilation with decreased perfusion
Rationale: A pulmonary embolism is a blockage of a pulmonary artery by a thrombus.
This obstructs blood flow to a segment of the lung. Alveoli in this area continue to be
ventilated but are not perfused, creating a high V/Q ratio (dead space) and leading to
significant hypoxemia.
Question 10: A patient with a history of asthma is experiencing an acute
exacerbation. Auscultation of the lungs reveals absent breath sounds in the left
lower lobe. This finding is most likely indicative of which of the following
complications?
A. Pneumothorax
B. Atelectasis
C. Pleural effusion
D. Mucus plugging
CORRECT ANSWER: D. Mucus plugging
Rationale: In an acute asthma exacerbation, inflammation leads to bronchospasm,
mucosal edema, and increased mucus production. A thick mucus plug can completely
obstruct a bronchus, preventing airflow and leading to absent breath sounds over the
affected area.
Question 11: A patient with heart failure develops pulmonary edema. The
underlying mechanism for the fluid accumulation in the lungs is best described
as:
A. Decreased capillary hydrostatic pressure
B. Increased capillary hydrostatic pressure
C. Decreased capillary oncotic pressure
D. Increased capillary permeability
CORRECT ANSWER: B. Increased capillary hydrostatic pressure
Rationale: Left-sided heart failure results in increased pressure in the pulmonary veins
and capillaries. This elevated hydrostatic pressure forces fluid out of the pulmonary
capillaries and into the interstitial space and alveoli, resulting in pulmonary edema.
