ATI LPN
Exam Questions on Respiratory System Questions
Question 1 of 5
Site of most / major airway resistance is:
Correct Answer: D
Rationale: medium-sized bronchi (2-4 mm diameter) are the primary resistance site due to turbulent flow and cumulative cross-sectional area peak. Choice A (trachea) and B (main bronchi) have low resistance (large diameter). Choice C (large bronchi) contributes less. Choice E (bronchioles) has high total area, reducing resistance. Per Poiseuille's law, resistance peaks where radius narrows before area increases, making D the major site.
Question 2 of 5
Which responds quickly to chemicals injected into the pulmonary circulation?
Correct Answer: D
Rationale: J (juxtacapillary) receptors in alveolar walls respond rapidly to pulmonary capillary chemicals (e.g., edema, emboli), causing dyspnea. Choice A (central) senses CSF pH, not pulmonary blood. Choice B (carotid) and C (aortic) monitor systemic arterial changes. Choice D (stretch receptors) responds to lung inflation. J receptors, vagally innervated, detect interstitial changes instantly, unlike systemic chemoreceptors, making F the precise match.
Question 3 of 5
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.
Question 4 of 5
Which of the following is INCORRECT?
Correct Answer: A
Rationale: HbS shifts the O₂ curve right (lower affinity, P₅₀ up), not left, due to altered structure (valine for glutamic acid). Choice B is true (Bohr effect). Choice C is correct (CO affinity ≈240x O₂). Choice D is accurate; COHb left-shifts remaining Hb's curve. HbS's sickling enhances O₂ unloading, contradicting A's left shift, making it false.
Question 5 of 5
Regarding pulmonary perfusion, which statement is INCORRECT?
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.