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PA3.1-4,PA4.1 | Inflammation & Healing — Practice Quiz
Practice
12 questions · Untimed · Unlimited attempts
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A 28-year-old construction worker sustains a nail-puncture wound to the palm. Within 10 minutes the wound site shows redness, warmth, swelling, and pain. Which vascular event is FIRST responsible for the redness and warmth?
A
Arteriolar dilation increasing blood flow (hyperaemia)
✓
B
Increased vascular permeability with protein exudation
C
Emigration of neutrophils through venular endothelium
D
Platelet aggregation at the site of endothelial injury
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During the early phase of acute inflammation, histamine is released from mast cells. What is the PRIMARY mechanism by which histamine increases vascular permeability?
A
Direct endothelial cytotoxicity causing necrosis of venular walls
B
Activation of the complement cascade producing C3a and C5a
C
Endothelial cell contraction creating intercellular gaps in postcapillary venules
✓
D
Leucocyte-mediated proteolytic digestion of the basement membrane
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A pleural fluid sample is sent to the lab. Results show: protein 18 g/L (serum 68 g/L), LDH 80 U/L (serum 200 U/L), specific gravity 1.010, and few mesothelial cells. Which type of fluid is this, and what is the most likely underlying mechanism?
A
Exudate — increased vascular permeability due to inflammation
B
Transudate — increased hydrostatic pressure or decreased oncotic pressure
✓
C
Exudate — lymphatic obstruction with chyle accumulation
D
Transudate — direct endothelial necrosis from bacterial toxins
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A medical student is studying the neutrophil recruitment cascade. She notes that neutrophils roll along the endothelium before firm adhesion. Which molecules mediate the ROLLING step?
A
ICAM-1 on endothelium binding CD11/CD18 (β2-integrins) on neutrophils
B
P-selectin and E-selectin on endothelium binding sialyl-Lewis X on neutrophils
C
P-selectin on endothelium binding PSGL-1 on neutrophils, and E-selectin binding sialyl-Lewis X
✓
D
PECAM-1 (CD31) on both neutrophils and endothelium mediating homophilic binding
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A neutrophil has engulfed a bacterium into a phagosome. Which sequence CORRECTLY describes the killing of the bacterium by the respiratory burst?
A
NADPH oxidase → superoxide (O₂⁻) → hydrogen peroxide (H₂O₂) → hypochlorous acid (HOCl) via myeloperoxidase
B
Myeloperoxidase → superoxide (O₂⁻) → NADPH oxidase → hydrogen peroxide (H₂O₂) → HOCl
C
NADPH oxidase → superoxide → H₂O₂; myeloperoxidase uses H₂O₂ + Cl⁻ to generate HOCl
✓
D
iNOS → nitric oxide (NO) → peroxynitrite (ONOO⁻) → myeloperoxidase → HOCl
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A 45-year-old patient with rheumatoid arthritis is started on a COX-2 selective inhibitor (celecoxib). Which pair of inflammatory mediators will be MOST directly reduced by this drug?
A
Prostaglandin E₂ and prostacyclin (PGI₂)
✓
B
TNF-α and IL-1β
C
Prostaglandin E₂ and thromboxane A₂
D
Histamine and serotonin
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A 22-year-old medical student develops lobar pneumonia. CXR shows right lower lobe consolidation; sputum is rusty-coloured. Which morphologic pattern of acute inflammation does this BEST represent?
A
Serous inflammation with watery, low-protein transudate
B
Fibrinous inflammation lining a body cavity surface
C
Suppurative (purulent) inflammation with abscess formation
D
Fibrinous inflammation filling the alveolar spaces (lobar pneumonia)
✓
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A 35-year-old HIV-negative immunocompetent patient is diagnosed with pulmonary tuberculosis. Bronchoscopic biopsy shows granulomas with central caseous necrosis and giant cells with nuclei arranged in a horseshoe pattern at the periphery. Which giant-cell type is this, and what distinguishes it from a foreign-body giant cell?
A
Langhans giant cell — nuclei at periphery in a horseshoe/arc; associated with TB, sarcoid, and foreign-body reactions equally
B
Langhans giant cell — nuclei peripherally arranged in a horseshoe/arc; found in hypersensitivity (type IV) granulomas; foreign-body GC has randomly scattered central nuclei and no caseous necrosis
✓
C
Foreign-body giant cell — nuclei randomly scattered; foreign-body GC is diagnostic of TB when caseous necrosis is present
D
Touton giant cell — central nuclei with peripheral foamy cytoplasm; diagnostic of granulomatous infection
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A 52-year-old patient presents with fever, malaise, anorexia, and night sweats. Laboratory findings: Hb 9.8 g/dL, WBC 14,000/μL, ESR 98 mm/hr, CRP 87 mg/L. Which statement BEST explains the elevated ESR in this setting?
A
ESR rises because the WBC count increases, causing blood to become more viscous
B
CRP directly agglutinates red cells by binding phosphocholine on their surface, increasing sedimentation
C
Acute-phase proteins (fibrinogen, α₁-antitrypsin, CRP) coat RBCs, reducing the zeta potential and promoting rouleaux formation
D
Acute-phase proteins — principally fibrinogen — coat RBCs, reducing their surface charge (zeta potential) and accelerating rouleaux formation and sedimentation
✓
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A 65-year-old diabetic woman undergoes a laparotomy for a perforated appendix. Post-operatively her wound dehisces. Histology of the wound edge at day 10 shows abundant new capillaries (angiogenesis), proliferating fibroblasts, and loose collagen in an oedematous matrix. Which tissue type does this REPRESENT, and what is its clinical significance?
A
Fibrous scar — indicates completed healing with maximal tensile strength
B
Granulation tissue — provisional scaffold for healing; its formation is a prerequisite before re-epithelialisation and scar maturation
C
Granulation tissue — provisional scaffold of new capillaries, fibroblasts, and loose collagen that fills wounds before scar maturation; characteristic of secondary-intention healing
✓
D
Chronic granulomatous inflammation — giant cells forming in response to the suture material
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A clinical vignette: A 70-year-old malnourished patient with a Hb of 7 g/dL and serum albumin of 22 g/L undergoes elective inguinal hernia repair. Six weeks post-op the wound breaks down. Which combination of factors MOST comprehensively explains the impaired healing in this patient?
A
Anaemia alone — tissue hypoxia reduces collagen synthesis by prolyl hydroxylase
B
Hypoalbuminaemia alone — reduced oncotic pressure causes wound oedema impairing oxygen delivery
C
Advanced age alone — reduced fibroblast proliferative capacity and growth factor signalling
D
Malnutrition (protein deficiency reducing collagen substrate + vitamin C deficiency impairing hydroxylation), anaemia (tissue hypoxia), and hypoalbuminaemia (wound oedema + immune deficiency)
✓
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A 25-year-old woman notices a raised, firm, itchy scar on her shoulder 8 months after a minor surgical excision. The scar extends beyond the original wound margins. A dermatologist diagnoses a keloid. Which statement BEST distinguishes a keloid from a hypertrophic scar?
A
A keloid remains within the original wound boundaries; a hypertrophic scar extends beyond them
B
A keloid extends beyond original wound margins and does NOT regress spontaneously; a hypertrophic scar stays within wound limits and may regress
✓
C
A keloid consists of excessive Type I collagen but normal fibroblast number; a hypertrophic scar has excess fibroblasts with normal collagen
D
Both keloid and hypertrophic scar regress with time, but keloid recurs after excision while hypertrophic scar does not
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