Distal convoluted tubules show:

Correct Answer: C

Rationale: Distal convoluted tubules (DCT) lack a brush border (proximal feature), have indistinct boundaries due to fewer microvilli, and show basal striations not wide diameter. This distinguishes DCT histology, key for reabsorption/secretion roles, contrasting with proximal traits.

Correct Answer: B

Rationale: Renal threshold (~180 mg/dL or mg%) is the plasma glucose level where reabsorption saturates, spilling into urine not rate (mg/min) or higher values. This distinguishes glucose homeostasis, critical for diabetes, contrasting with saturation definitions.

Correct Answer: B

Rationale: Renin comes from juxtaglomerular cells (afferent arteriole), not efferent macula densa (DCT), fenestrated capillaries (glomerulus), and collecting tubules (rays) are correct. This distinguishes renin's source, key for RAAS, contrasting with vascular misplacement.

Correct Answer: A

Rationale: In sarcoidosis, hypercalciuria stems from absorptive hypercalciuria excess vitamin D from granulomas increases gut calcium absorption, spilling into urine. Renal hypercalciuria involves kidney leak, not primary in sarcoidosis absorption drives it. Low calcium intake reduces, not raises, urinary calcium opposite effect. Reduced oxalate excretion is unrelated oxalate binds calcium, not source here. Absorptive mechanism distinguishes sarcoidosis' systemic etiology, key to its stone risk, unlike renal, dietary, or oxalate factors.

Correct Answer: A

Rationale: Emphysematous cystitis shows a 'cobble stoned' or 'beaded necklace' X-ray appearance gas bubbles in bladder wall from infection (e.g., E. coli). Papillary necrosis lacks gas sloughed papillae. Pelvic lipomatosis shows fat, not gas radiolucent. Malacoplakia has plaques, not gas pattern chronic inflammation. Gas-driven cobble stoning distinguishes emphysematous cystitis, key to its radiographic diagnosis, unlike necrosis, fat, or plaque conditions.