Which two main tissue regions do the kidneys have?

• A. Cortex and Medulla
• B. Medulla and Cortex
• C. Cortex and Pelvis
• D. Medulla and Pelvis

Answer: (A)

Two main tissue regions make up the kidney: the cortex and the medulla. The cortex sits on the outside and contains the glomeruli and the proximal and distal tubules where filtration and initial processing of filtrate occur. The medulla is the inner region, housing the loops of Henle and the collecting ducts, organized into renal pyramids where urine is concentrated as it moves toward the pelvis. The pelvis itself is not a tissue region of the kidney’s functional tissue; it’s a central collecting area that funnels urine into the ureter. Therefore, cortex and medulla are the correct paired regions.