Concerning the function of the glomerular Mesangial cells:

Correct Answer: D

Rationale: Mesangial cells contract to reduce GFR area and phagocytose debris not produce systemic angiotensin II (juxtaglomerular cells). 'A and C' are true, distinguishing mesangial roles, critical for filtration regulation, contrasting with renin-angiotensin.

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.

Correct Answer: A

Rationale: TURBT electrocautery can stimulate the obturator nerve runs near bladder lateral wall, causing thigh adduction (obturator kick). Sciatic nerve (leg) is distant unrelated. Genitofemoral (genital) and ilioinguinal (inguinal) innervate other areas bladder surgery spares them. Obturator's proximity distinguishes it, key to this surgical complication, unlike distant or regional nerves.