ATI LPN
Questions for the Respiratory System Questions
Question 1 of 5
Ventilatory response to COâ‚‚ is reduced by all EXCEPT:
Correct Answer: D
Rationale: decreasing breathing work (e.g., assisted ventilation) doesn't reduce COâ‚‚ response it may enhance it by easing effort. Choice A (sleep), B (barbiturates), C (age), and E (athletes/divers) depress sensitivity via CNS suppression or adaptation. COâ‚‚ drives ventilation via central chemoreceptors; reduced work lowers resistance, not chemosensitivity. D stands out as the exception.
Question 2 of 5
The major site of resistance in the bronchial tree is the:
Correct Answer: B
Rationale: medium-sized bronchi (2-4 mm diameter) are the major resistance site due to turbulent flow and peak cumulative resistance before total cross-sectional area rises. Choice A (segmental) and Choice D (large bronchioles) have less resistance due to size or area. Choice C (small bronchi) contributes less individually. Choice E (terminal bronchioles) has high total area, minimizing resistance. Poiseuille's law and airway branching show resistance peaks in medium bronchi, where radius narrows significantly, making B the primary site.
Question 3 of 5
Which respond to blood CO₂, not O₂ or H⺠concentrations?
Correct Answer: A
Rationale: central chemoreceptors respond to blood COâ‚‚ via CSF pH changes (COâ‚‚ diffuses, forms Hâº), not directly to Oâ‚‚ or Hâº. Choice B (carotid) and C (aortic) sense POâ‚‚, PCOâ‚‚, and pH. Choice D (stretch) is mechanical. Located in the medulla, central receptors drive 70-80% of COâ‚‚ response, insensitive to hypoxia, making A the specific match.
Question 4 of 5
The transport of which of the following gases is DIFFUSION LIMITED?
Correct Answer: D
Rationale: CO is diffusion-limited its high Hb affinity and low solubility prevent equilibration in 0.75 s transit. Choice A (Oâ‚‚) is perfusion-limited at rest (equilibrates in 0.25 s). Choice B (Nâ‚‚O) is perfusion-limited (high solubility). Choice C (COâ‚‚) equilibrates fast (20x Oâ‚‚ diffusion). Choice E (halothane) is perfusion-limited. CO's slow uptake (Dâ‚—CO measures lung capacity) distinguishes D as diffusion-limited.
Question 5 of 5
Which of the following DOES NOT decrease lung compliance?
Correct Answer: D
Rationale: advancing age increases compliance (loss of elastic recoil, e.g., emphysema-like), not decreases. Choice A (LV failure) reduces it via edema (stiffer lungs). Choice B (atelectasis) decreases via collapse. Choice C (fibrosis) lowers it (scarring). Choice E (raised PCWP) mimics edema. Aging weakens lung elastin, raising compliance (e.g., 250 vs. 200 mL/cm Hâ‚‚O), distinguishing D as the exception.