Bronchiectasis

Correct Answer: B

Rationale: Bronchiectasis is sometimes caused by influenza infection (B), among pathogens like adenovirus or Staph aureus. Choice A is false; obstruction and infection together drive it, not infection alone. Choice C is incorrect; it's a feature of IBD (e.g., ulcerative colitis). Choice D is wrong; sputum is purulent, not clear. Choice E (CF from obstruction/infection) is true. Page 727 notes B's role post-influenza necrosis dilates airways, a known trigger, distinguishing it over A's sole etiology or D's sputum error.

Correct Answer: D

Rationale: All listed features of Moraxella catarrhalis (A-C) are true, making D (none true) incorrect. Choice A is correct; it causes pneumonia in elderly. Choice B is accurate; it's second to H influenzae in COPD exacerbations. Choice C is true; it's a key otitis media pathogen in kids. Choice E (all true) aligns with text. Page 748 confirms A-C's roles M catarrhalis's gram-negative diplococcus nature targets vulnerable groups, contradicting D's denial with its established pathogenicity across these conditions.

Correct Answer: C

Rationale: Fungal infections like histoplasmosis resemble tuberculosis (C), with granulomas. Choice A is false; it's not immunocompromised-specific (also immunocompetent). Choice B is incorrect; inflammation is granulomatous, not suppurative. Choice D is wrong; Histoplasma produces yeast, not hyphae (others do). Choice E (common in HIV) is true. Page 754 details C's mimicry Histoplasma's TB-like lesions confuse diagnosis, unlike A's restriction or D's morphology error.

Correct Answer: B

Rationale: The larynx separates the upper and lower respiratory tracts. The upper tract includes the nasal cavity, pharynx, and larynx, handling air intake and conditioning. The lower tract trachea, bronchi, and lungs focuses on gas exchange. The larynx, with its vocal cords and epiglottis, marks this boundary, preventing food entry into the airway during swallowing. Bronchi, within the lungs, are lower tract structures. The epiglottis, part of the larynx, aids closure but isn't the divider itself. Palatine tonsils, in the pharynx, fight infection, not division. The larynx's role as a structural and functional transition point is key, linking air passage to voice production while guarding the lower airway, essential for respiratory system organization.

Correct Answer: C

Rationale: Varicella-zoster virus (VZV) causes shingles, a reactivation of latent virus from childhood chickenpox, manifesting as painful rash along nerve paths. Rubella virus causes German measles, a milder rash illness. Measles virus leads to systemic fever and rash, not nerve-specific. Variola major virus caused smallpox, eradicated, with skin lesions, not shingles' pattern. VZV's latency in dorsal root ganglia, triggered by stress or immunity decline, distinguishes it antivirals like acyclovir manage it, unlike measles or rubella's supportive care. This specificity matters for treatment and vaccination (e.g., Zostavax), highlighting VZV's unique neurotropic behavior in respiratory-origin viruses.