Nephrons

A nephron is the functional unit of the kidney. It comprises two main parts — the renal corpuscle and renal tubule.

The renal corpuscle, where blood plasma filtration occurs, contains the glomerulus — a capillary network, and Bowman's capsule — a double-walled epithelial cup surrounding the glomerulus.

The renal tubule, which receives the filtered fluid or glomerular filtrate, has three sections — the proximal convoluted tubule, the loop of Henle or nephron loop, and the distal convoluted tubule.

Inside each nephron, the renal corpuscle and proximal and distal convoluted tubules are in the cortex, with the loop of Henle extending toward the medulla.

There are about 1 million nephrons in each kidney, and 80 to 85% of them are located in the cortex. These cortical nephrons have shorter nephron loops.

The remaining 15 to 20% of nephrons are juxtamedullary nephrons. They are present deeper in the cortex near the medulla and feature longer loops extending further into the medulla.