Cell injury and death Practice Questions
20 free Cell injury and death practice questions for the USMLE Step 1. Tap an option to answer — you get instant feedback, the correct answer, and a detailed explanation for every question.
A patient suffers from prolonged ischemia to the heart leading to irreversible injury. Which of the following is the earliest sign of irreversible cell injury?
- A Cellular swelling
- B Loss of membrane integrity
- C Nuclear chromatin clumping
- D Decreased oxidative phosphorylation
Correct answer: Loss of membrane integrity
Loss of membrane integrity is the hallmark of irreversible injury, allowing leakage of intracellular enzymes and ions.
A biopsy shows eosinophilic cytoplasm and pyknosis. These findings are characteristic of which process?
- A Reversible injury
- B Coagulative necrosis
- C Liquefactive necrosis
- D Fat necrosis
Correct answer: Coagulative necrosis
Coagulative necrosis displays preserved cell outlines, intense eosinophilia, and nuclear changes including pyknosis.
A child ingests acetaminophen in toxic amounts, leading to centrilobular liver necrosis. Which mechanism underlies this injury?
- A ATP depletion
- B Free radical formation
- C Calcium influx
- D Lysosomal enzyme leakage
Correct answer: Free radical formation
Acetaminophen overdose generates toxic free radicals via CYP450 metabolism, damaging hepatocytes.
An elderly man with chronic hypertension develops enlargement of the individual cardiac muscle cells. This is an example of:
- A Hyperplasia
- B Hypertrophy
- C Metaplasia
- D Dysplasia
Correct answer: Hypertrophy
Hypertension increases cardiac workload, leading to enlargement of myocytes rather than increased cell number.
A smoker develops squamous metaplasia in the bronchial epithelium. Which statement is true?
- A It is an irreversible change
- B It increases mucus production
- C It predisposes to dysplasia
- D It is a form of cell necrosis
Correct answer: It predisposes to dysplasia
Squamous metaplasia is reversible but increases susceptibility to dysplasia and cancer.
A patient exposed to ionizing radiation shows DNA fragmentation. Which process is most characteristic?
- A Apoptosis
- B Coagulative necrosis
- C Liquefactive necrosis
- D Fat necrosis
Correct answer: Apoptosis
Radiation activates intrinsic apoptotic pathways, causing DNA fragmentation and cell shrinkage.
A patient with pancreatitis shows chalky white deposits in the abdominal cavity. What process explains this finding?
- A Caseous necrosis
- B Fat necrosis
- C Fibrinoid necrosis
- D Liquefactive necrosis
Correct answer: Fat necrosis
Pancreatic lipases cause fat necrosis, producing saponification and chalky deposits.
Atherosclerotic plaques rupture due to cellular injury from oxidized LDL. What type of cellular accumulation is present?
- A Lipofuscin
- B Hemosiderin
- C Fatty change
- D Glycogen
Correct answer: Fatty change
Fatty change occurs in conditions like atherosclerosis where lipid-laden macrophages accumulate.
A patient has dystrophic calcification in an area of caseous necrosis. What serum calcium level is expected?
- A Low
- B Normal
- C High
- D Critically high
Correct answer: Normal
Dystrophic calcification occurs despite normal serum calcium, as calcium deposits in necrotic tissues.
A patient undergoing apoptosis displays cell shrinkage, membrane blebbing, and intact membranes. Which enzyme family mediates this?
- A Proteases
- B Caspases
- C Phospholipases
- D Lysozymes
Correct answer: Caspases
Caspases are central executors of apoptosis, leading to controlled cell dismantling.
A man with chronic passive congestion of the liver develops hemosiderin-laden macrophages. What pigment is responsible?
- A Lipofuscin
- B Bilirubin
- C Iron
- D Melanin
Correct answer: Iron
Hemosiderin results from iron accumulation, seen in chronic venous congestion.
A patient with hypoxic injury shows cellular swelling. What is the primary cause of this change?
- A Increased anaerobic glycolysis
- B Failure of Na+/K+ pump
- C Protein leakage
- D DNA fragmentation
Correct answer: Failure of Na+/K+ pump
ATP depletion impairs the Na+/K+ pump, causing intracellular sodium and water accumulation.
A man with tuberculosis has granulomas with caseous necrosis. Which characteristic describes this necrosis?
- A Preserved cell outlines
- B Cheese-like appearance
- C Liquefied tissue
- D Fat saponification
Correct answer: Cheese-like appearance
Caseous necrosis appears cheese-like and is typical of granulomatous infections such as TB.
A patient with autoimmune vasculitis shows fibrinoid necrosis in the vessel walls. What causes this appearance?
- A Lipid accumulation in the wall
- B Immune complex deposition
- C Calcium salt precipitation
- D Fat saponification by lipase
Correct answer: Immune complex deposition
Fibrinoid necrosis results from immune complex deposition and plasma protein leakage into vessel walls.
Cells undergoing apoptosis release cytochrome c. Which cellular structure releases it?
- A Nucleus
- B Endoplasmic reticulum
- C Mitochondria
- D Lysosomes
Correct answer: Mitochondria
Mitochondria release cytochrome c, initiating the caspase cascade in apoptosis.
A patient with severe ischemia to the brain develops liquefactive necrosis. What causes this pattern?
- A High brain lipid content
- B Calcium influx into cells
- C Excessive collagen deposition
- D Complete loss of blood supply
Correct answer: High brain lipid content
Brain tissue is rich in lipids and undergoes enzymatic digestion, leading to liquefactive necrosis.
A patient with chronic inflammation demonstrates lipofuscin accumulation. What does this pigment represent?
- A Oxidized lipid residues
- B Iron overload in tissue
- C Abnormal protein accumulation
- D Excess glycogen storage
Correct answer: Oxidized lipid residues
Lipofuscin accumulates due to wear-and-tear oxidation of lipids and is seen in aging cells.
A patient exposed to carbon tetrachloride (CCl4) develops hepatocyte swelling. What mechanism explains this?
- A CCl3 free radical formation
- B Cytosolic calcium overload
- C Nuclear DNA fragmentation
- D Lysosomal membrane rupture
Correct answer: CCl3 free radical formation
CCl4 is metabolized into CCl3 free radicals, causing membrane damage and cell swelling.
Cells undergoing necrosis release inflammatory signals. Which feature distinguishes necrosis from apoptosis?
- A Cell shrinkage
- B Formation of apoptotic bodies
- C Loss of membrane integrity
- D DNA laddering
Correct answer: Loss of membrane integrity
Necrotic cells lose membrane integrity, causing inflammation, unlike apoptosis which preserves membranes.
A patient with reperfusion injury shows increased free radical production. Which enzyme system contributes to this?
- A Xanthine oxidase
- B Cytochrome oxidase
- C Hexokinase
- D Na+/K+ ATPase
Correct answer: Xanthine oxidase
Reperfusion activates xanthine oxidase, generating reactive oxygen species that damage tissues.