Video - Kidney histology

The kidneys are a pair of bean-shaped organs located on either side of the spine, below the ribcage. The functions of the kidneys are to remove waste products and excess water from the blood, to regulate blood pressure, and to produce erythropoietin (EPO), which helps to produce red blood cells.

The functional tissue of the kidney, or parenchyma, has an outer renal cortex and inner renal medulla. The medulla is organized into cone-like structures called renal pyramids and renal columns in between the pyramids, which are extensions of the renal cortex. At the junction between the cortex and medulla are millions of functional units called nephrons. Each nephron can be divided into its major parts: The renal corpuscle, proximal convoluted tubule, the loop of Henle, distal convoluted tubule, and collecting duct.