A patient with restrictive lung disease will have a relatively normal?

Correct Answer: D

Rationale: Restrictive lung disease (e.g., fibrosis) stiffens lungs, reducing expansion. Forced vital capacity (FVC) drops (e.g., from 4-5 L to 2-3 L) due to limited volume. FEV1 also falls (e.g., 3-4 L to 1.5-2 L) proportionally, but the FEV1/FVC ratio stays normal or high (≥80%), as both decrease similarly, unlike obstructive disease (<70%). Ventilation/perfusion (V/Q) ratio may rise in fibrosis (ventilation falls more than perfusion), not remaining normal. FEV1 and FVC individually are reduced, not normal. The FEV1/FVC ratio's preservation is a restrictive hallmark volume-limited, not airflow-obstructed making it the relatively normal value, key for spirometric diagnosis and distinguishing restrictive from obstructive patterns.

Correct Answer: B

Rationale: Initial: VT = 1000 ml, VD = 200 ml, RR = 20/min. VE = VT × RR = 1000 × 20 = 20 L/min; VA = (VT - VD) × RR = (1000 - 200) × 20 = 16 L/min. T: VT = 2000 ml, RR = 10/min; VE = 2000 × 10 = 20 L/min (constant), VA = (2000 - 200) × 10 = 18 L/min (increases). V: VT = 500 ml, RR = 40/min; VE = 500 × 40 = 20 L/min (constant), VA = (500 - 200) × 40 = 12 L/min (decreases). T's higher VT boosts VA despite lower RR; V's lower VT cuts VA as dead space dominates. Option B (T: VE constant, VA increases; V: VE constant, VA decreases) fits, showing VT's impact on alveolar efficiency at fixed VE.

Correct Answer: B

Rationale: Evaporation from oceans is the primary source of atmospheric water vapor, contributing ~86% of global input (~400,000 km³/year), due to oceans' vast surface (~71% of Earth) and solar-driven evaporation. Transpiration from plants adds ~10% (~50,000 km³/year), significant but secondary. Sublimation of ice is minor, limited by polar cold and area. Volcanic eruptions inject water vapor (~1% of total), but episodically. Oceans' dominance, per hydrologic cycle data (e.g., Trenberth), drives humidity, clouds, and precipitation, with ~90% of atmospheric vapor (1.3×10¹³ m³) cycling through evaporation, making it the key source, far exceeding terrestrial or geological inputs.

Correct Answer: C

Rationale: The quadrangular membrane is a fibroelastic layer in the larynx, intrinsic (B), spanning from the epiglottis to arytenoids. Its upper margin forms aryepiglottic folds (A), and its lower margin thickens into vestibular (false) folds (D). Innervation (C) is sensory via the internal laryngeal nerve (above cords), not the recurrent laryngeal nerve, which supplies muscles below (e.g., vocalis). C is the exception recurrent laryngeal doesn't innervate this membrane.

Correct Answer: B

Rationale: The urinary bladder's epithelium is transitional (B), a stratified type unique to the urinary tract, allowing stretch as the bladder fills. Its surface cells shift from cuboidal to flattened, adapting to volume changes without rupturing. Stratified squamous (A) lines the skin and mouth, resisting abrasion, not stretching. Simple squamous (C), a single thin layer, lines alveoli and capillaries for diffusion, unsuitable for the bladder's mechanical demands. Pseudostratified columnar (D) is in the trachea, with cilia, irrelevant here. Transitional epithelium's ability to transition shapes under tension makes B the correct choice for the bladder's dynamic environment.