The calibre of extra-alveolar vessels is primarily determined by:

Correct Answer: C

Rationale: extra-alveolar vessel caliber (e.g., arterioles, venules) is primarily determined by lung volume, expanding with inflation (radial traction). Choice A affects alveolar capillaries (Zone 2/3). Choice B (artery pressure) influences flow, not caliber directly. Choice D (output) and E (fluid) are secondary. As volume rises (e.g., FRC to TLC), vessel resistance drops, distinguishing C as the mechanical driver.

Correct Answer: B

Rationale: E. coli endotoxin causes pulmonary vasoconstriction (e.g., sepsis-induced hypertension), not venodilatation. Choice A is true; apex perfusion is lower (gravity). ' flow rises 3-6x (5 to 15-30 L/min). Choice D is accurate; resistance increases at low volumes (vessel collapse). Choice E (Zone 2) is true. Endotoxin triggers thromboxane/prostaglandins, constricting vessels, contradicting B's dilation, making it the error.

Correct Answer: A

Rationale: exercise does not increase PaCO₂ it remains ≈40 mmHg as ventilation matches CO₂ production (e.g., 0.2 to 4 L/min). Choice B is true; PAO₂ rises slightly (e.g., 100 to 110 mmHg) with hyperventilation. ' PaCO₂ stays stable. Choice D is accurate; PaO₂ holds at ≈95-100 mmHg in healthy lungs. Choice E (increased PvCO₂) is true (e.g., 46 to 50 mmHg). Exercise boosts V̇E (e.g., 6 to 120 L/min), preventing PaCO₂ rise, making A the exception in normal physiology.

Correct Answer: A

Rationale: Pneumonia secondary to influenza often leads to ineffective breathing patterns due to lung inflammation, mucus buildup, and impaired gas exchange, making it a primary nursing diagnosis. The client may experience shortness of breath or rapid, shallow breathing as the body struggles to oxygenate properly, a direct result of flu-related respiratory complications. Disturbed sleep pattern is plausible, as coughing and discomfort disrupt rest, supporting recovery challenges. Self-care deficit: bathing could apply if fatigue or weakness prevents personal hygiene, common in severe illness. Chronic pain, however, implies a long-term condition unrelated to acute pneumonia or flu, which typically cause temporary discomfort like myalgia or pleuritic pain. The nurse prioritizes ineffective breathing pattern because it addresses the life-threatening respiratory impact of pneumonia, requiring interventions like oxygen therapy or positioning. This diagnosis aligns with the clinical presentation of flu complications, guiding care to stabilize the client's respiratory status and prevent further deterioration.

Correct Answer: D

Rationale: The 2009 H1N1 influenza virus was a reassortant strain with genes from pig (swine flu viruses), bird (avian influenza), and human sources, reflecting its zoonotic origins. Pigs act as ‘mixing vessels,' allowing genetic exchange between flu strains from different species, which occurred here, creating a novel virus that jumped to humans. Bird genes contributed via prior avian flu strains, while human genes enabled efficient human-to-human transmission, fueling the pandemic. Cat-derived flu genes aren't documented in H1N1's makeup felines aren't typical influenza reservoirs. Pig genes alone don't tell the full story; it's the combination that matters. The nurse educates on this multi-species origin to highlight how influenza evolves, emphasizing vigilance for zoonotic threats, a key infection control lesson from H1N1's global spread, informing strategies like surveillance and vaccination.