The ______ limb of the Loop of Henle is impermeable to water.

Correct Answer: A

Rationale: The ascending limb is water-impermeable pumps NaCl, concentrating medulla (e.g., countercurrent multiplier). Descending is permeable water exits. Thick/thin are subsets ascending key. Impermeability distinguishes it, critical for urine concentration, unlike permeable or vague options.

Correct Answer: B

Rationale: Cystitis is bladder infection e.g., E. coli common (mucosa). Urethritis is urethra not bladder. Pyelonephritis is kidney higher. Nephritis is inflammation not specific infection. Cystitis's location distinguishes it, critical for bladder pathology, unlike adjacent or vague terms.

Correct Answer: C

Rationale: Juxtaglomerular (JG) cells secrete renin e.g., JGA responds to low BP. Macula densa senses NaCl signals JG, doesn't secrete. Glomerular epithelial (podocytes) filter not secrete. Basement membrane is structural not cellular. JG's renin role distinguishes it, key to RAAS, unlike sensing or structural parts.

Correct Answer: A

Rationale: Renal diabetes (glycosuria) spills glucose into urine at low blood levels e.g., defective PCT transporters (threshold <180 mg/dL). Hemorrhage unrelated blood loss issue. ADH affects water not glucose. Youth prevalence is diabetes mellitus not renal. Low-threshold spill distinguishes it, critical for renal glycosuria, unlike unrelated causes.

Correct Answer: B

Rationale: Cl⁻ reabsorption follows Na electrostatic attraction (e.g., PCT Na /Cl⁻ cotransport). Aldosterone boosts Na indirectly Cl⁻, not permeability. Ca² retention is separate unrelated. Osmotic gradient drives water not Cl⁻ directly. Na attraction distinguishes it, critical for electroneutrality, unlike hormonal or osmotic drivers.