Which is the INCORRECT pairing in bronchi/bronchioles:

Correct Answer: A

Rationale: cholinergic discharge (acetylcholine, parasympathetic) causes bronchoconstriction, not bronchodilation. Choice B is true; β₂-agonists (e.g., albuterol) activate adrenergic receptors, relaxing bronchial smooth muscle. ' β₂-agonists increase mucus secretion, a secondary effect to dilation. Choice D is true; vasoactive intestinal peptide (VIP) promotes bronchodilation by relaxing smooth muscle. Cholinergic stimulation, via vagus nerve, contracts bronchioles, increasing resistance opposite to bronchodilation's airway widening. This reflects autonomic balance: parasympathetic constricts, sympathetic (β₂) dilates. A's reversal of this physiology misrepresents airway control, where bronchodilation aids airflow (e.g., asthma treatment), while cholinergic effects narrow airways for rest or protection. Thus, A is the incorrect pairing.

Correct Answer: C

Rationale: lung surface area (≈70-100 m²) is ≈30 times the skin's (≈2 m² in adults). Choice A (3x, ≈6 m²) is too low. Choice B (10x, ≈20 m²) underestimates. Choice D (100x, ≈200 m²) overestimates. Choice E is false. The alveolar expanse, via 300 million units, maximizes gas exchange, making C accurate.

Correct Answer: D

Rationale: mean pulmonary artery pressure (mPAP) is ≈15 mmHg in a healthy adult (systolic ≈25, diastolic ≈8). Choice A (2 mmHg) is far too low, below venous levels. Choice B (5 mmHg) underestimates pulmonary circulation. Choice C (8 mmHg) is diastolic, not mean. Choice E (25 mmHg) is systolic, not mean. mPAP reflects low-resistance pulmonary flow (≈1/10 systemic), driven by right ventricular output. Catheterization data confirm 15 mmHg as normal, distinguishing it from systemic pressures (≈100 mmHg mean), making D the precise value.

Correct Answer: A

Rationale: asthma doesn't inherently increase compliance (lung stiffness), but options like emphysema (chronic asthma complication) do via loss of elastic recoil (compliance rises, e.g., 300 mL/cm Hâ‚‚O). Choice B (edema) decreases compliance (stiffer lungs). Choice C (hypertension) affects vessels, not compliance directly. Choice D (atelectasis) and E (fibrosis) reduce compliance (collapse, scarring). Asthma's acute bronchoconstriction doesn't alter compliance, but chronic changes mimic emphysema's high compliance, making A the relative increase among options.

Correct Answer: D

Rationale: FEV₁ is ≈80% of FVC in healthy adults (FEV₁/FVC ratio ≈ 0.75-0.85). Choice A (50%) suggests obstruction (e.g., COPD). Choice B (60%) and C (70%) are low for normals. Choice E (90%) is high, nearing restriction. FEV₁ (forced expiratory volume in 1 s) reflects airway patency; FVC (forced vital capacity) is total expirable volume. A ratio of 80% indicates normal flow, making D standard.