Which blood vessels surround the loops of Henle?

Correct Answer: A

Rationale: Vasa recta surround the loop of Henle, enabling countercurrent exchange, unlike peritubular capillaries (PCT/DCT), interlobular arteries (cortex), or efferent arterioles (glomerulus). This specifies medullary circulation, key for urine concentration, contrasting with cortical vessels.

Correct Answer: C

Rationale: PCT actively reabsorbs ~70% of filtered sodium, not 10%, 1%, or 99% (total includes later). This quantifies sodium handling, key for fluid balance, contrasting with full reabsorption myths.

Correct Answer: C

Rationale: Erythropoietin from kidneys boosts RBC production, not renin (pressure), aldosterone (sodium), or somatomedin (growth). This defines hematopoietic role, key for anemia, contrasting with RAAS hormones.

Correct Answer: C

Rationale: Peristalsis propels urine through ureters, not gravity (positional), hydrostatic (filtration), or osmotic (concentration). This defines ureteral motility, key for urine transport, contrasting with passive forces.

Correct Answer: B

Rationale: Renal corpuscle includes glomerulus and Bowman's capsule, not PCT, loop, or DCT (tubular). This defines filtration unit, key for GFR, contrasting with tubular segments.