Inflammation and repair Practice Questions
22 free Inflammation and repair 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.
Which of the following is one of the cardinal signs of acute inflammation?
- A Metaplasia
- B Hyperplasia
- C Rubor (redness)
- D Dysplasia
Correct answer: Rubor (redness)
Rubor (redness) is one of the classic cardinal signs of acute inflammation, resulting from vasodilation and increased blood flow to the affected area.
During the vascular phase of acute inflammation, which change occurs first?
- A Leukocyte chemotaxis
- B Vasodilation
- C Fibrosis
- D Granulation tissue formation
Correct answer: Vasodilation
The vascular phase begins with vasodilation and increased blood flow, which is the earliest change in acute inflammation.
Which cell type is the predominant leukocyte in the first 24 hours of acute inflammation?
- A Lymphocytes
- B Eosinophils
- C Neutrophils
- D Plasma cells
Correct answer: Neutrophils
Neutrophils are the first responders and predominate in the initial phase of acute inflammation, especially within the first 24–48 hours.
What is the main function of macrophages during the wound-healing process after acute inflammation?
- A Trigger the initial vasodilation
- B Phagocytose debris and release growth factors
- C Form fibrin blood clots
- D Produce new keratinocytes
Correct answer: Phagocytose debris and release growth factors
Macrophages phagocytose debris and dead cells and secrete growth factors and cytokines that promote granulation tissue formation and progression to the proliferative phase.
Which of the following describes the correct sequence of wound healing phases under normal circumstances?
- A Inflammation → Hemostasis → Remodeling → Proliferation
- B Hemostasis → Inflammation → Proliferation → Remodeling
- C Proliferation → Hemostasis → Inflammation → Remodeling
- D Inflammation → Proliferation → Hemostasis → Remodeling
Correct answer: Hemostasis → Inflammation → Proliferation → Remodeling
The classic sequence is hemostasis (clot formation), then inflammation, followed by proliferation (granulation tissue, angiogenesis, epithelialization), and finally remodeling (maturation of scar).
Which extracellular matrix component helps form the initial scaffold for migrating cells during early wound healing?
- A Type I collagen
- B Elastin
- C Fibronectin
- D Keratin
Correct answer: Fibronectin
Fibronectin binds to fibrin and forms a provisional matrix that supports cell migration and organization early in wound healing.
Which outcome of acute inflammation is most likely when the injurious agent is effectively removed and tissue architecture is intact?
- A Chronic inflammation
- B Abscess formation
- C Complete resolution
- D Fibrosis
Correct answer: Complete resolution
If the offending stimulus is removed and tissue structure is preserved, acute inflammation can resolve completely with restoration of normal tissue.
In chronic inflammation, which cell type becomes more predominant than neutrophils?
- A Basophils and mast cells
- B Macrophages and lymphocytes
- C Eosinophils predominantly
- D Neutrophils and platelets
Correct answer: Macrophages and lymphocytes
Chronic inflammation is characterized by infiltration of macrophages, lymphocytes (and often plasma cells) rather than neutrophils.
Which mediator released during acute inflammation increases vascular permeability and contributes to swelling (tumor)?
- A Epidermal growth factor
- B Histamine
- C Insulin
- D Dopamine
Correct answer: Histamine
Histamine (and other vasoactive mediators) causes endothelial cell contraction, increasing vascular permeability and leading to exudation of fluid, causing swelling.
What characterizes ‘granulation tissue’ during the proliferative phase of tissue repair?
- A Dense collagen bundles with few cells
- B New capillaries, fibroblasts, and loose ECM
- C Keratinized stratified epithelium
- D Necrotic debris and fibrin clot
Correct answer: New capillaries, fibroblasts, and loose ECM
Granulation tissue is composed of newly formed capillaries (angiogenesis), proliferating fibroblasts, and a loose ECM — preparing the wound for scar formation.
Which factor is least likely to impair normal wound healing?
- A Tissue hypoxia and ischemia
- B Protein-calorie malnutrition
- C Chronic glucocorticoid therapy
- D Good oxygenation and nutrition
Correct answer: Good oxygenation and nutrition
Optimal oxygenation and nutrition support normal wound healing; in contrast, hypoxia, malnutrition, and immunosuppressive therapy impair the process.
Which type of inflammation is characterized by formation of epithelioid macrophages and multinucleated giant cells often surrounded by lymphocytes?
- A Acute serous inflammation
- B Suppurative inflammation
- C Granulomatous inflammation
- D Fibrinous inflammation
Correct answer: Granulomatous inflammation
Granulomatous inflammation is a form of chronic inflammation marked by aggregates of epithelioid macrophages and giant cells, typically accompanied by lymphocytes.
Which event signals the beginning of the remodeling (maturation) phase of wound repair?
- A Initial fibrin clot formation
- B Neutrophil infiltration of the wound
- C Granulation tissue formation
- D Type III collagen replaced by type I
Correct answer: Type III collagen replaced by type I
During remodeling, the provisional ECM is reorganized — type III collagen is replaced by stronger type I collagen, and collagen fibers are reoriented to increase tissue strength.
What is the significance of Damage-Associated Molecular Patterns (DAMPs) in sterile inflammation?
- A Bacterial cell-wall products recognized by TLR4
- B Signals that inhibit leukocyte migration to tissue
- C Endogenous molecules released by injured cells
- D Plasma proteins that form the fibrin clot
Correct answer: Endogenous molecules released by injured cells
DAMPs such as HMGB1, ATP, uric acid and mitochondrial DNA are host molecules released by necrotic or stressed cells. They bind the same pattern-recognition receptors that sense microbial PAMPs, which is how tissue injury alone can drive a full inflammatory response with no infection present.
Which cytokines released by macrophages help drive the proliferative phase of wound healing by recruiting fibroblasts and promoting angiogenesis?
- A IL-10 and IL-4
- B TGF-β, PDGF, FGF
- C Insulin and glucagon
- D Erythropoietin
Correct answer: TGF-β, PDGF, FGF
Macrophages secrete growth factors like TGF-β, PDGF, and FGF which recruit fibroblasts and stimulate angiogenesis — essential for granulation tissue formation.
When inflammation fails to resolve and persists, leading to tissue damage and attempts at repair concurrently, what is this condition called?
- A Acute inflammation
- B Granulation
- C Chronic inflammation
- D Immediate healing
Correct answer: Chronic inflammation
Chronic inflammation represents persistent inflammatory stimulus where tissue damage and repair coexist over long periods, often leading to fibrosis or granuloma formation.
Which mediator group derived from arachidonic acid plays a major role in inflammation (vasodilation, increased permeability, leukocyte chemotaxis)?
- A Platelet-derived growth factors
- B Thromboxanes, prostaglandins, leukotrienes
- C Collagens and elastin fibers
- D Keratinocyte growth factors
Correct answer: Thromboxanes, prostaglandins, leukotrienes
Arachidonic acid metabolites — prostaglandins, thromboxanes and leukotrienes — are key inflammatory mediators that regulate vascular changes and leukocyte activity during inflammation.
Which of the following is a possible complication of wound healing when there is excessive fibroblast activity and collagen deposition beyond normal repair?
- A Delayed wound dehiscence
- B Keloid or scar contracture
- C Excessive angiogenesis
- D Enhanced epithelial regeneration
Correct answer: Keloid or scar contracture
Excessive fibroblast proliferation and collagen deposition can result in hypertrophic scars or keloids, which are pathological forms of repair.
Which statement best describes the difference between exudate and transudate in inflammation-related fluid accumulation?
- A Exudate is protein-poor; transudate is protein-rich
- B Exudate arises from vascular permeability; transudate from pressure imbalance
- C Transudate is purulent; exudate is clear serous
- D They are identical fluids with different names
Correct answer: Exudate arises from vascular permeability; transudate from pressure imbalance
Exudate forms when increased vascular permeability allows protein-rich fluid to leak; transudate results from hydrostatic or oncotic pressure changes, producing relatively protein-poor fluid.
In an acute inflammatory exudate dominated by neutrophils and dead cell debris, what is the correct term for this type of inflammation?
- A Serous inflammation
- B Fibrinous inflammation
- C Suppurative inflammation
- D Granulomatous inflammation
Correct answer: Suppurative inflammation
Suppurative or purulent inflammation is characterized by neutrophil-rich exudate, liquefactive necrosis, and pus formation.
Which factor is most critical in determining whether injured tissue regenerates completely or scars by fibrosis during repair?
- A Number of infiltrating neutrophils
- B Intact stem cells and basement membrane
- C Amount of leukotriene produced
- D Local rate of blood flow
Correct answer: Intact stem cells and basement membrane
Tissue regeneration requires viable parenchymal/regenerative cells and an intact basement membrane/ECM framework; if these are lost, repair proceeds via scar formation/fibrosis.
During which phase of wound healing does neovascularization (angiogenesis) primarily occur?
- A Hemostasis
- B Inflammation
- C Proliferation
- D Remodeling
Correct answer: Proliferation
Neovascularization and formation of granulation tissue occur during the proliferative phase, restoring blood supply to the healing tissue.