ATI LPN
Respiratory System Questions Questions
Question 1 of 5
The vagal afferent influence:
Correct Answer: D
Rationale: Choice D is likely correct (no answer provided); vagal afferents, via pulmonary stretch receptors (Hering-Breuer reflex), can prolong inspiration (‘breath-holding') if the pneumotaxic center, which limits inspiration, is destroyed. Choice A is false; vagal input (stretch) inhibits inspiration, not expiration. Choice B is wrong; it doesn't directly excite expiratory neurons. ' vagotomy causes deeper, slower breathing, not gasping (medullary damage does). Choice E (shallow rapid breathing) contradicts vagotomy's effect. Vagal afferents signal lung inflation, inhibiting inspiratory neurons via the medulla. Without pneumotaxic modulation, this can lock inspiration, mimicking breath-holding. Physiologically, D aligns with reflex disruption, making it the most consistent vagal influence description.
Question 2 of 5
The Law of Laplace implies that:
Correct Answer: D
Rationale: in a blood vessel, P = T/R (Laplace for cylinders), unlike alveoli (P = 2T/R). Choice A is false; alveoli use P = 2T/R (sphere with one surface). Choice B is wrong; soap bubbles (two surfaces) use P = 4T/R. Choice C is true but not the law's direct statement surfactant prevents this. Laplace relates pressure, tension, and radius; vessels (tubular) differ from spherical alveoli. D accurately applies this to vascular physiology.
Question 3 of 5
Regarding the Oâ‚‚ dissociation curve:
Correct Answer: B
Rationale: 2,3-DPG levels rise at altitude (hypoxia response), shifting the curve right. Choice A is true; PCO₂ shifts it right (Bohr effect). Choice C is false; deoxy-Hb is tense (T state), not relaxed (R state). Choice D is wrong; CO's affinity is ≈240x, shifting left by reducing available Hb, not curve shape. Altitude adaptation increases 2,3-DPG, aiding O₂ unloading (P₅₀ up), making B the accurate chronic response.
Question 4 of 5
Which rapidly adapting receptors lie between airway epithelial cells?
Correct Answer: D
Rationale: irritant receptors, between epithelial cells, adapt rapidly to mechanical/chemical stimuli (e.g., dust, smoke), triggering cough/bronchoconstriction. Choice A (central) is chemical, not airway-based. Choice B (carotid) and C (aortic) are vascular. Choice D (stretch) adapts slowly. Irritant receptors, vagally mediated, protect airways with quick responses, distinguishing E as the correct type.
Question 5 of 5
Which one of the following statements regarding ventilation is INCORRECT?
Correct Answer: C
Rationale: lower regions (base) ventilate better than upper (apex) due to gravity and compliance gradients. Choice A is true (TV ≈ 500 mL). Choice B is correct (dead space ≈ 150-160 mL). Choice D is accurate (Bohr's method). Choice E (none) is false. Base ventilation exceeds apex (e.g., 4:1 ratio upright), reflecting diaphragm motion and pleural pressure, making C the error.