ATI LPN
NCLEX PN Questions on Respiratory System Questions
Question 1 of 5
All of the following states decrease lung compliance EXCEPT
Correct Answer: D
Rationale: Emphysema (choice D) increases lung compliance, unlike others, making it the exception. Compliance is ease of lung expansion (ΔV/ΔP). Lung fibrosis (choice A) stiffens tissue, reducing compliance. Increased pulmonary venous pressure (choice B) causes edema, stiffening lungs. Prolonged unventilation (choice C) leads to atelectasis or surfactant loss, decreasing compliance. Alveolar edema (choice E) adds fluid, reducing elasticity. Emphysema destroys alveolar walls, reducing elastic recoil (floppy lungs), increasing compliance despite impaired function. This contrasts with restrictive conditions (A, B, C, E) that stiffen lungs, lowering compliance. Emphysema's obstructive nature raises FRC but eases expansion per pressure unit, distinguishing D as the state not decreasing compliance.
Question 2 of 5
Regarding bronchial tone:
Correct Answer: A
Rationale: substance P, a neuropeptide, causes bronchoconstriction by contracting smooth muscle. Choice B is false; sympathetic discharge (β₂-adrenergic) dilates bronchioles, not constricts. Choice C is wrong; parasympathetic (cholinergic) discharge constricts, not dilates. Choice D is true; bronchoconstriction peaks at 4 am due to circadian vagal tone. Choice E is false; VIP dilates, not constricts. Substance P, released from sensory nerves, mediates inflammation and constriction (e.g., asthma), increasing resistance. This contrasts with autonomic control: sympathetic relaxes, parasympathetic tightens. A's accuracy reflects its role in airway tone regulation.
Question 3 of 5
Concerning the pulmonary circulation in a normal man:
Correct Answer: D
Rationale: in West's Zone 1 (apex, upright), alveolar pressure (PA) exceeds arterial (Pa) and venous (Pv) pressure, stopping flow. Choice A is false; mean pulmonary artery pressure is ≈15 mmHg, not 25 (systemic range). Choice B is wrong; hypoxia increases pulmonary vascular resistance (vasoconstriction), not decreases. Choice C is true; resistance is lower at total lung capacity (TLC) than functional residual capacity (FRC) due to vessel stretching. Zone 1's high PA (e.g., 0 to +2 cmH₂O) vs. low Pa (e.g., 10 cmH₂O at apex) collapses capillaries, a normal gravitational effect. D accurately reflects this no-flow state.
Question 4 of 5
Which is not inactivated by the lungs?
Correct Answer: D
Rationale: vasopressin (ADH) passes through the lungs unchanged. Choice A (serotonin) is inactivated by monoamine oxidase. Choice B (bradykinin) is broken down by ACE. Choice C (leukotrienes) are metabolized or excreted. Choice D (prostaglandin Eâ‚‚) is inactivated by pulmonary enzymes. The lung's endothelium clears amines, peptides, and eicosanoids, but vasopressin, a systemic hormone, resists metabolism, maintaining its antidiuretic role. E's inert passage aligns with pulmonary metabolic selectivity.
Question 5 of 5
Which are believed to be important in the early stages of exercise?
Correct Answer: D
Rationale: joint and muscle receptors (mechanoreceptors) drive early exercise hyperpnea via proprioceptive feedback to the medulla. Choice A (central) responds to COâ‚‚/pH later. Choice B (carotid) and C (aortic) sense hypoxia/COâ‚‚, secondary in normoxia. Choice D (stretch) modulates pattern. Muscle spindles and tendon organs signal effort within seconds, initiating ventilation rise before chemical changes, making H key in exercise onset.