ATI LPN
Questions on Respiratory System Questions
Question 1 of 5
The respiratory quotient:
Correct Answer: D
Rationale: RQ = 1.0 for carbohydrate metabolism (VCOâ‚‚ = VOâ‚‚). Choice A is true; high V/Q (apex) lowers RQ (less COâ‚‚ relative to Oâ‚‚). Choice B is false; base RQ is lower (higher perfusion). Choice C is wrong; RQ = VCOâ‚‚ / VOâ‚‚, not reverse. D reflects metabolic stoichiometry, a standard definition.
Question 2 of 5
Which respond to POâ‚‚ and PCOâ‚‚ but not pH?
Correct Answer: C
Rationale: aortic bodies respond to POâ‚‚ and PCOâ‚‚ but are less sensitive to pH than carotid bodies (which sense all three). Choice A (central) detects pH via COâ‚‚. Choice B (carotid) includes pH sensitivity. Choice D (stretch) is mechanical. Aortic bodies, in the aortic arch, prioritize gas tensions, with pH a secondary signal via carotid dominance, making C the best fit.
Question 3 of 5
Metabolic functions of the lung include all of the following EXCEPT:
Correct Answer: B
Rationale: the lung converts angiotensin I to II (AII) via ACE but doesn't metabolize AII degradation occurs elsewhere (e.g., liver). Choice A is true (ACE activity). Choice C is correct (bradykinin inactivation). Choice D is accurate (serotonin uptake). Choice E (arachidonic acid) occurs via cyclooxygenase. The lung's ACE role is synthetic, not catabolic for AII, making B the exception.
Question 4 of 5
Total lung capacity is equal to:
Correct Answer: D
Rationale: total lung capacity (TLC) = vital capacity (VC) + residual volume (RV), e.g., 4.8 + 1.2 = 6 L in men. Choice A (VC + TV) overcounts inspiratory volume. Choice B (VC + FRC) double-counts RV and ERV. Choice C (TV + RV) is too small (≈1.7 L). TLC encompasses all lung volume (RV + ERV + TV + IRV), and VC (ERV + TV + IRV) plus RV completes it. E aligns with standard lung volume definitions.
Question 5 of 5
Which of the following DOES NOT shift the oxygen-haemoglobin dissociation curve to the right?
Correct Answer: A
Rationale: decreased phosphate lowers 2,3-DPG, shifting the O₂ dissociation curve left (higher Hb-O₂ affinity, P₅₀ down). Choice B (altitude) increases 2,3-DPG, shifting right. Choice C (cortisol) may indirectly raise 2,3-DPG via metabolism, shifting right. Choice D (decreased pH) shifts right (Bohr effect, H⺠reduces affinity). Choice E (aldosterone) has minimal direct effect but isn't listed. Phosphate depletion (e.g., starvation) reduces 2,3-DPG, countering right-shift factors like CO₂, temperature, or hypoxia, making A the exception in this context.