Which of the followings is the mechanism of action of thiazide?

Correct Answer: A

Rationale: Thiazides inhibit Na+/Cl- cotransporter in the DCT, promoting diuresis, not stimulating it or affecting the loop of Henle (furosemide's site). This distinguishes thiazide's action, key for hypertension treatment, contrasting with loop diuretics or stimulatory misconceptions.

Correct Answer: B

Rationale: Hyperaldosteronism increases K+ excretion, causing hypokalemia not acidosis (hyperkalemia), insulin deficiency, or beta blockers (minimal effect). This links aldosterone to potassium, critical for endocrine-renal interplay, contrasting with other conditions.

Correct Answer: C

Rationale: Urine acidification (H+ secretion) peaks in the collecting duct via intercalated cells not PCT, DCT, or ascending loop (diluting). This specifies pH regulation site, critical for acid-base, contrasting with earlier segments.

Correct Answer: D

Rationale: Renal lobule includes a medullary ray and adjacent cortex not pyramid alone, pyramid+cortex (lobe), or inter-pyramid cortex. This defines lobule anatomy, critical for histology, contrasting with lobe or cortex misdefinitions.

Correct Answer: A

Rationale: PCT reabsorbs ~80-90% of filtered bicarbonate not DCT, collecting duct, or ascending loop (no HCO3- transport). This specifies primary reabsorption site, critical for acid-base, contrasting with later segments.