Which sensation occurs at a bladder volume of 150-300 mL?

Correct Answer: B

Rationale: At 150-300 mL, the bladder triggers the first urge to void stretch receptors signal (e.g., micturition reflex onset). Fullness comes at 300-400 mL escalation. Discomfort at 400-600 mL stronger stretch. Pain at 600-700 mL overdistension. Initial urge distinguishes it, critical for normal voiding cues, unlike later sensations.

Correct Answer: D

Rationale: A GFR marker (e.g., inulin) shouldn't be metabolized must stay intact for clearance (e.g., excreted fully). Not secreted ensures filtration-only true. Not reabsorbed keeps GFR accurate correct. Non-toxic is essential safety. Metabolism distinguishes the error, critical for marker purity, unlike filtration-only criteria.

Correct Answer: C

Rationale: CO₂ combining with H₂O via extracellular carbonic anhydrase is false occurs intracellularly (e.g., PCT enzyme). H secretion and H₂CO₃ formation are true HCO₃⁻ reclaimed. Poor permeability holds indirect reabsorption. Intracellular site distinguishes the error, key to bicarbonate mechanism, unlike correct steps.

Correct Answer: C

Rationale: Spironolactone (aldosterone inhibitor) decreases K secretion blocks Na reabsorption, reducing K exchange (e.g., collecting duct). High plasma K increases secretion stimulates. Proximal diuretic (e.g., acetazolamide) raises distal K increases. Alkalosis boosts K secretion H /K shift. Aldosterone block distinguishes it, key to K sparing, unlike secretion-enhancing factors.

Correct Answer: C

Rationale: Angiotensin II receptors are in the zona glomerulosa stimulate aldosterone release (e.g., adrenal cortex). Juxtaglomerular cells produce renin not receptors. Macula densa senses lacks these. Intercalated cells manage pH not angiotensin. Adrenal location distinguishes it, key to RAAS, unlike renal or tubular sites.