Schematic presentation of the mammalian kidney cross-section.
Left: Each kidney is comprised of three layers encapsulated by a fibrous outer layer called the renal capsule membrane. The three kidney layers include the peripheral layer, called the cortex, and the inner layer, called the medulla, which is subdivided into the inner and outer medulla.
Right: The medulla is arranged in multiple pyramidal structures that together with the overlying cortex comprise a renal lobe. Nephrons, the functional units of the kidney, are found within the renal lobes and bear a characteristic structure that includes a glomerulus and an epithelial tubule that loops down into the medulla and is compartmentalized into the proximal tubule, Loop of Henle and the distal tubule (color legends).