The triangular-shaped divisions of the kidney's medulla are known as

• A. Pyramids
• B. Lobes
• C. Calyces
• D. Columns

Answer: (A)

Renal pyramids are the triangular-shaped divisions of the kidney’s medulla. They are formed by the bundled tubules and collecting ducts that run through the medulla, giving a cone-like appearance with the base toward the cortex and the apex (papilla) facing the minor calyx. The spaces between the pyramids are renal columns, extensions of cortical tissue that separate them. Urine produced in the cortex drains into the papilla, then into the minor calyces, and onward to major calyces and the renal pelvis. This distinguishes pyramids from calyces (urine-collecting sacs), columns (cortical tissue between pyramids), and lobes (a pyramid plus surrounding cortex and columns).