Renin is released in response to ________.

Correct Answer: B

Rationale: Decreased BP triggers renin not increased BP, ACE (downstream), or diuretics (effect). This initiates RAAS, key for pressure regulation, contrasting with high-pressure states.

Correct Answer: D

Rationale: Kidney stones include calcium phosphate, oxalate, and uric acid not HCO3 (bicarbonate, soluble). This distinguishes stone composition, key for treatment, contrasting with non-stone solutes.

Correct Answer: D

Rationale: Kidneys span T12 to L3 not higher thoracic or extended lumbar. This specifies position, vital for radiology, contrasting with incorrect spans.

Correct Answer: C

Rationale: The distal convoluted tubule excels in secretion lacks microvilli (reabsorption-focused), emphasizing secretion (e.g., H , K ) via active transport. The proximal tubule dominates reabsorption ~65% of filtrate (e.g., glucose, Na ) but secretes organics (e.g., creatinine). The Loop of Henle focuses on concentration minimal secretion. The collecting duct adjusts urine via reabsorption/secretion (e.g., H by intercalated cells) less secretion-centric. The distal tubule's secretion role, tied to fine-tuning ion balance, distinguishes it, critical for acid-base and potassium regulation, unlike reabsorption-heavy or concentration-focused segments.

Correct Answer: B

Rationale: Tubular secretion is the selective transfer from peritubular capillaries to the tubular lumen removes waste (e.g., H , drugs) into urine. Lumen-to-capillary is reabsorption opposite. Reabsorption conserves e.g., glucose. Filtration occurs at glomerulus not tubular. Selective capillary-to-lumen movement distinguishes it, critical for excretion, unlike reabsorption or filtration processes.