In extrinsic asthma

Correct Answer: C

Rationale: Inhaled allergens elicit a T_H2-dominated response favoring IgE production (C) in extrinsic asthma. Choice A is true; IgE cross-linking releases mediators (e.g., histamine) opening tight junctions. Choice B is false; it's Type I hypersensitivity (IgE-mediated), not Type II (antibody-cell). Choice D is incorrect; major basic protein (eosinophil-derived) damages epithelium, not inhibits. Choice E (antigen penetration) follows A. Page 725 (Fig 15-11) confirms C's T_H2 role IL-4/IL-13 drive IgE, distinguishing it over B's type error or D's protective claim.

Correct Answer: A

Rationale: Normal pulmonary blood pressure is 1/8 of systemic pressure (A), ≈15 mmHg vs. 120 mmHg. Choice B is false; pulmonary hypertension is usually secondary (e.g., lung disease). Choice C is incorrect; emphysema increases resistance via capillary loss, not vasoconstriction. Choice D is wrong; it's defined as mean pressure ≥25 mmHg, not tied to systemic. Choice E (sudden death from PE) is distinct. Page 743 confirms A's ratio low-pressure pulmonary circuit contrasts with B's primary claim or C's mechanism.

Correct Answer: A

Rationale: Community-acquired pneumonitis can mimic ARDS's alveolar damage pattern (A), e.g., diffuse injury. Choice B is false; involvement varies (patchy or lobar). Choice C is incorrect; pleural effusions are uncommon. Choice D is wrong; white cell count is mildly elevated. Choice E (no fibrosis) is true. Page 751 notes A's similarity organisms like Mycoplasma cause ARDS-like exudates in epidemics (schools/prisons), unlike B's uniformity or C's effusion claim.

Correct Answer: A

Rationale: Normally, 15 mL of serous acellular fluid lubricates pleura (A), maintaining low friction. Choice B is false; most effusions are secondary (e.g., CHF), not primary. Choice C is incorrect; hemorrhagic pleuritis is tumor-related. Choice D is wrong; hemothorax is from trauma/aortic rupture. Choice E (empyema from lung infection) is true. Page 766 (Table 15-14) confirms A's physiology small volume prevents adhesion, distinguishing it over B's primary claim or C's etiology error.

Correct Answer: D

Rationale: The common cold is typically caused by rhinoviruses (most frequent), coronaviruses (e.g., pre-COVID strains), and adenoviruses, all targeting upper respiratory epithelium, leading to sniffles and cough. Varicella-zoster virus (VZV) causes chickenpox and shingles, not colds it's a herpesvirus affecting skin and nerves, not primarily respiratory mucosa. While cold viruses spread via droplets and self-resolve, VZV involves systemic rash and latency, requiring antivirals like acyclovir in severe cases. This distinction matters: cold management is supportive, but VZV has vaccination (e.g., Zostavax) and different transmission dynamics, emphasizing accurate viral identification in respiratory versus systemic infections.