The Functional Unit of Kidney: Nephron

The Functional Unit of Kidney: Nephron

The nephron is the kidney's functional unit that removes waste from the body. Each kidney has more than a million nephrons in the renal cortex, which gives it a granular appearance on sagittal section.

There are 2 types of nephrons. The cortical nephrons, which make up about 85 percent, are found deep in the renal cortex, while the juxtamedullary nephrons, which make up about15 percent of total nephrons, lie close to the medulla.

The nephron consists of a renal corpuscle, a tubule, and a capillary network that originates from the small cortical arteries. Each renal corpuscle is composed of a glomerulus (a network of capillaries) and a Bowman's capsule(the cup-shaped chamber that surrounds it.

The glomerulus connects to a long, convoluted renal tubule which is divided into three functional parts. These consist of the loop of Henle (nephritic loop), the proximal convoluted tubule, and the distal convoluted tubule, which empties into the collecting ducts. These collecting ducts fuse together and enter the papillae of the renal medulla.

Urine passes through the renal medulla as a fluid with high sodium content and leaves through the renal papillae, into the renal calyces, into the renal pelvis, and into the bladder through the ureter.