SCI 225 Pathophysiology Midterm Examination
Nightingale College | Latest 2026/2027 Advanced
Comprehensive Version Total Questions: 150 | Format:
Multiple Choice | Difficulty: Advanced/Hard | Time
Allowed: 180 Minutes
EXAMINATION INSTRUCTIONS:
1. Select the single best answer for each question.
2. Read each question carefully, paying attention to clinical clues and pathophysiological
mechanisms.
3. Consider the underlying disease processes, compensatory mechanisms, and systemic
effects.
4. Mark your answers on the provided answer sheet.
5. This examination contains 150 questions covering all major pathophysiological systems.
6. You have 180 minutes to complete the examination.
SECTION A: CELLULAR INJURY, ADAPTATION, AND DEATH (Questions 1-15)
1. A 72-year-old patient with chronic obstructive pulmonary disease and right-sided heart
failure presents with muscle wasting, generalized weakness, and a 15-pound unintentional
weight loss over 3 months. Physical examination reveals bilateral pitting edema, jugular
venous distention, and diminished breath sounds with prolonged expiration. The muscle
wasting observed is most directly attributable to which cellular adaptive response?
• A. Physiologic hypertrophy of skeletal muscle fibers
• B. Pathologic hyperplasia of connective tissue elements
, • C. Cellular atrophy resulting from decreased protein synthesis and increased proteolysis
• D. Metaplastic transformation of muscle cells to adipose tissue
• E. Dysplastic changes in muscle cell nuclei
Correct Answer: C. Cellular atrophy resulting from decreased protein synthesis and increased
proteolysis
Rationale: This patient exhibits chronic disease-induced muscle wasting (cachexia) secondary to
heart failure and COPD. Cellular atrophy is characterized by decreased protein synthesis and
increased proteolysis via the ubiquitin-proteasome pathway. In chronic disease states,
inflammatory cytokines (TNF-α, IL-6) and glucocorticoids promote muscle catabolism. This is not
hypertrophy (A), which is increased cell size; hyperplasia (B) is increased cell number;
metaplasia (D) is cell type replacement; dysplasia (E) is abnormal cellular growth with nuclear
atypia. The correct answer reflects the fundamental mechanism of atrophy in chronic disease.
2. A 58-year-old man with a 30-year history of hypertension and type 2 diabetes mellitus
presents with progressive exertional dyspnea, orthopnea, and paroxysmal nocturnal dyspnea.
Echocardiography reveals concentric left ventricular hypertrophy with an ejection fraction of
55%. A myocardial biopsy shows myocyte enlargement with increased sarcomere organization
and interstitial fibrosis. Which of the following best describes the molecular mechanism
underlying this patient's cardiac adaptation?
• A. Activation of the PI3K/AKT/mTOR pathway leading to physiologic hypertrophy
• B. Activation of the Gq/PLC-β pathway leading to pathologic hypertrophy with fetal gene
reactivation
• C. Increased apoptosis of cardiac myocytes with compensatory hyperplasia
• D. Metaplastic transformation of cardiac fibroblasts to contractile elements
• E. Loss of mitochondrial oxidative capacity with anaerobic adaptation
Correct Answer: B. Activation of the Gq/PLC-β pathway leading to pathologic hypertrophy
with fetal gene reactivation
Rationale: This patient demonstrates pathologic hypertrophy secondary to chronic pressure
overload from hypertension. Pathologic hypertrophy is mediated by Gq protein-coupled
receptor activation, leading to PLC-β activation, increased intracellular calcium, and activation of
calcineurin and NFAT, resulting in fetal gene program reactivation (ANF, BNP, β-MHC). This differs
from physiologic hypertrophy (A), which is mediated by PI3K/AKT/mTOR and maintains normal
,gene expression. Fibrosis is a hallmark of pathologic hypertrophy, absent in physiologic
adaptations. Apoptosis with hyperplasia (C) is incorrect; metaplasia (D) is cell type conversion;
mitochondrial loss (E) occurs in late stages but is not the primary mechanism.
3. A 45-year-old woman with chronic gastroesophageal reflux disease presents with
worsening heartburn, regurgitation, and a sensation of a lump in her throat. Endoscopic
biopsy of the distal esophagus reveals replacement of stratified squamous epithelium with
intestinal-type columnar epithelium containing goblet cells. The pathologist documents the
presence of Barrett's esophagus. Which of the following statements BEST describes the
pathophysiological significance of this finding?
• A. This represents a reversible adaptive change that will resolve with acid suppression
therapy
• B. This is a premalignant condition associated with an increased risk of esophageal
adenocarcinoma
• C. This demonstrates squamous metaplasia, which is a protective response to chronic
irritation
• D. This indicates acute inflammatory injury that will heal with scarring
• E. This represents normal embryologic remnant tissue in the esophagus
Correct Answer: B. This is a premalignant condition associated with an increased risk of
esophageal adenocarcinoma
Rationale: Barrett's esophagus is a metaplastic change from squamous to intestinal-type
columnar epithelium in response to chronic GERD. This is not a reversible, protective change
(A,C); it represents a premalignant condition with a 30-125 fold increased risk of esophageal
adenocarcinoma. While metaplasia is theoretically reversible if the stimulus is removed, once
specialized intestinal metaplasia develops, the risk of malignancy persists. It is not acute
inflammation with scarring (D) nor embryonic remnant tissue (E). The presence of goblet cells
(intestinal metaplasia) is the key diagnostic feature and carries significant malignant potential.
4. A 65-year-old patient with severe atherosclerosis and peripheral vascular disease presents
with acute-onset severe pain, pallor, and pulselessness in the right lower extremity. Emergent
surgical revascularization is performed, but the patient develops reperfusion injury. Which of
the following mechanisms is PRIMARILY responsible for reperfusion injury following ischemic
tissue injury?
, • A. Restoration of ATP synthesis leading to mitochondrial swelling
• B. Generation of reactive oxygen species from xanthine oxidase and mitochondrial
dysfunction
• C. Activation of the complement cascade
• D. Release of histamine from mast cells
• E. Apoptosis mediated by caspase activation
Correct Answer: B. Generation of reactive oxygen species from xanthine oxidase and
mitochondrial dysfunction
Rationale: Reperfusion injury is primarily caused by oxidative stress from reactive oxygen
species (ROS) generation. During ischemia, ATP degradation produces hypoxanthine, and
xanthine dehydrogenase is converted to xanthine oxidase. Upon reperfusion, oxygen is
reintroduced, and xanthine oxidase converts hypoxanthine to xanthine, generating superoxide
and hydrogen peroxide. Additionally, mitochondrial dysfunction during ischemia leads to
electron transport chain damage, causing further ROS production upon reperfusion. While ATP
restoration (A) occurs, it paradoxically contributes to calcium overload and oxidative injury.
Complement activation (C), histamine release (D), and apoptosis (E) play roles but are
secondary to the primary oxidative mechanism.
5. A 52-year-old patient with chronic alcoholism and malnutrition is admitted with confusion,
nystagmus, and ataxia. MRI reveals bilateral hyperintensities in the mammillary bodies. The
patient's history is significant for Wernicke-Korsakoff syndrome. At the cellular level, which of
the following biochemical processes is MOST directly impaired in this condition?
• A. Oxidative phosphorylation due to mitochondrial DNA mutations
• B. Thiamine-dependent enzymatic reactions in glucose metabolism
• C. Protein folding and trafficking due to endoplasmic reticulum stress
• D. DNA repair mechanisms due to nucleotide depletion
• E. Fatty acid oxidation due to carnitine deficiency
Correct Answer: B. Thiamine-dependent enzymatic reactions in glucose metabolism
Rationale: Wernicke-Korsakoff syndrome results from thiamine (vitamin B1) deficiency, which is
critical for several enzymes in glucose metabolism: pyruvate dehydrogenase (PDH), α-
ketoglutarate dehydrogenase (α-KGDH), and transketolase. These enzymes are essential for ATP
Nightingale College | Latest 2026/2027 Advanced
Comprehensive Version Total Questions: 150 | Format:
Multiple Choice | Difficulty: Advanced/Hard | Time
Allowed: 180 Minutes
EXAMINATION INSTRUCTIONS:
1. Select the single best answer for each question.
2. Read each question carefully, paying attention to clinical clues and pathophysiological
mechanisms.
3. Consider the underlying disease processes, compensatory mechanisms, and systemic
effects.
4. Mark your answers on the provided answer sheet.
5. This examination contains 150 questions covering all major pathophysiological systems.
6. You have 180 minutes to complete the examination.
SECTION A: CELLULAR INJURY, ADAPTATION, AND DEATH (Questions 1-15)
1. A 72-year-old patient with chronic obstructive pulmonary disease and right-sided heart
failure presents with muscle wasting, generalized weakness, and a 15-pound unintentional
weight loss over 3 months. Physical examination reveals bilateral pitting edema, jugular
venous distention, and diminished breath sounds with prolonged expiration. The muscle
wasting observed is most directly attributable to which cellular adaptive response?
• A. Physiologic hypertrophy of skeletal muscle fibers
• B. Pathologic hyperplasia of connective tissue elements
, • C. Cellular atrophy resulting from decreased protein synthesis and increased proteolysis
• D. Metaplastic transformation of muscle cells to adipose tissue
• E. Dysplastic changes in muscle cell nuclei
Correct Answer: C. Cellular atrophy resulting from decreased protein synthesis and increased
proteolysis
Rationale: This patient exhibits chronic disease-induced muscle wasting (cachexia) secondary to
heart failure and COPD. Cellular atrophy is characterized by decreased protein synthesis and
increased proteolysis via the ubiquitin-proteasome pathway. In chronic disease states,
inflammatory cytokines (TNF-α, IL-6) and glucocorticoids promote muscle catabolism. This is not
hypertrophy (A), which is increased cell size; hyperplasia (B) is increased cell number;
metaplasia (D) is cell type replacement; dysplasia (E) is abnormal cellular growth with nuclear
atypia. The correct answer reflects the fundamental mechanism of atrophy in chronic disease.
2. A 58-year-old man with a 30-year history of hypertension and type 2 diabetes mellitus
presents with progressive exertional dyspnea, orthopnea, and paroxysmal nocturnal dyspnea.
Echocardiography reveals concentric left ventricular hypertrophy with an ejection fraction of
55%. A myocardial biopsy shows myocyte enlargement with increased sarcomere organization
and interstitial fibrosis. Which of the following best describes the molecular mechanism
underlying this patient's cardiac adaptation?
• A. Activation of the PI3K/AKT/mTOR pathway leading to physiologic hypertrophy
• B. Activation of the Gq/PLC-β pathway leading to pathologic hypertrophy with fetal gene
reactivation
• C. Increased apoptosis of cardiac myocytes with compensatory hyperplasia
• D. Metaplastic transformation of cardiac fibroblasts to contractile elements
• E. Loss of mitochondrial oxidative capacity with anaerobic adaptation
Correct Answer: B. Activation of the Gq/PLC-β pathway leading to pathologic hypertrophy
with fetal gene reactivation
Rationale: This patient demonstrates pathologic hypertrophy secondary to chronic pressure
overload from hypertension. Pathologic hypertrophy is mediated by Gq protein-coupled
receptor activation, leading to PLC-β activation, increased intracellular calcium, and activation of
calcineurin and NFAT, resulting in fetal gene program reactivation (ANF, BNP, β-MHC). This differs
from physiologic hypertrophy (A), which is mediated by PI3K/AKT/mTOR and maintains normal
,gene expression. Fibrosis is a hallmark of pathologic hypertrophy, absent in physiologic
adaptations. Apoptosis with hyperplasia (C) is incorrect; metaplasia (D) is cell type conversion;
mitochondrial loss (E) occurs in late stages but is not the primary mechanism.
3. A 45-year-old woman with chronic gastroesophageal reflux disease presents with
worsening heartburn, regurgitation, and a sensation of a lump in her throat. Endoscopic
biopsy of the distal esophagus reveals replacement of stratified squamous epithelium with
intestinal-type columnar epithelium containing goblet cells. The pathologist documents the
presence of Barrett's esophagus. Which of the following statements BEST describes the
pathophysiological significance of this finding?
• A. This represents a reversible adaptive change that will resolve with acid suppression
therapy
• B. This is a premalignant condition associated with an increased risk of esophageal
adenocarcinoma
• C. This demonstrates squamous metaplasia, which is a protective response to chronic
irritation
• D. This indicates acute inflammatory injury that will heal with scarring
• E. This represents normal embryologic remnant tissue in the esophagus
Correct Answer: B. This is a premalignant condition associated with an increased risk of
esophageal adenocarcinoma
Rationale: Barrett's esophagus is a metaplastic change from squamous to intestinal-type
columnar epithelium in response to chronic GERD. This is not a reversible, protective change
(A,C); it represents a premalignant condition with a 30-125 fold increased risk of esophageal
adenocarcinoma. While metaplasia is theoretically reversible if the stimulus is removed, once
specialized intestinal metaplasia develops, the risk of malignancy persists. It is not acute
inflammation with scarring (D) nor embryonic remnant tissue (E). The presence of goblet cells
(intestinal metaplasia) is the key diagnostic feature and carries significant malignant potential.
4. A 65-year-old patient with severe atherosclerosis and peripheral vascular disease presents
with acute-onset severe pain, pallor, and pulselessness in the right lower extremity. Emergent
surgical revascularization is performed, but the patient develops reperfusion injury. Which of
the following mechanisms is PRIMARILY responsible for reperfusion injury following ischemic
tissue injury?
, • A. Restoration of ATP synthesis leading to mitochondrial swelling
• B. Generation of reactive oxygen species from xanthine oxidase and mitochondrial
dysfunction
• C. Activation of the complement cascade
• D. Release of histamine from mast cells
• E. Apoptosis mediated by caspase activation
Correct Answer: B. Generation of reactive oxygen species from xanthine oxidase and
mitochondrial dysfunction
Rationale: Reperfusion injury is primarily caused by oxidative stress from reactive oxygen
species (ROS) generation. During ischemia, ATP degradation produces hypoxanthine, and
xanthine dehydrogenase is converted to xanthine oxidase. Upon reperfusion, oxygen is
reintroduced, and xanthine oxidase converts hypoxanthine to xanthine, generating superoxide
and hydrogen peroxide. Additionally, mitochondrial dysfunction during ischemia leads to
electron transport chain damage, causing further ROS production upon reperfusion. While ATP
restoration (A) occurs, it paradoxically contributes to calcium overload and oxidative injury.
Complement activation (C), histamine release (D), and apoptosis (E) play roles but are
secondary to the primary oxidative mechanism.
5. A 52-year-old patient with chronic alcoholism and malnutrition is admitted with confusion,
nystagmus, and ataxia. MRI reveals bilateral hyperintensities in the mammillary bodies. The
patient's history is significant for Wernicke-Korsakoff syndrome. At the cellular level, which of
the following biochemical processes is MOST directly impaired in this condition?
• A. Oxidative phosphorylation due to mitochondrial DNA mutations
• B. Thiamine-dependent enzymatic reactions in glucose metabolism
• C. Protein folding and trafficking due to endoplasmic reticulum stress
• D. DNA repair mechanisms due to nucleotide depletion
• E. Fatty acid oxidation due to carnitine deficiency
Correct Answer: B. Thiamine-dependent enzymatic reactions in glucose metabolism
Rationale: Wernicke-Korsakoff syndrome results from thiamine (vitamin B1) deficiency, which is
critical for several enzymes in glucose metabolism: pyruvate dehydrogenase (PDH), α-
ketoglutarate dehydrogenase (α-KGDH), and transketolase. These enzymes are essential for ATP
