The nephron is the basic filtering unit of kidneys. Each kidney has 1-1.5 million nephrons in it.

The filtration of blood takes place in Bowman’s capsule under a very high pressure. Finally, the waste products go to a network of collecting tubules which finally meet in a common collecting duct. This collecting duct joins the ureter which carries urine to the urinary bladder for excretion.

Structure and functioning of nephrons

• Bowman’s capsule: The Bowman’s Capsule is a cup-shaped structure which houses the ‘glomerulus’. For this reason, it is also known as the ‘glomerular capsule’. Fluids flowing through the glomerulus are removed from larger particles.
• Proximal convoluted tubule or proximal tubule: This is the first twisted region after the Bowman’s capsule. It lies in the cortex. The reabsorption of essential substances takes place here. This is known as tubular reabsorption.
• Loop of Henle: The long, hairpin loop after the proximal tubule is called ‘loop of Henle’. It is extended from the cortex down into the medulla and back.
• Distal convoluted tubule or distal tubule: This is the second twisted portion of the nephron after the loop of Henle. It is located in the cortex.
• Collecting duct: This is the long straight portion after the distal tubule. The distal convoluted tubule is the most distal (distant) portion of the nephron and is responsible for the reabsorption of sodium, and water.

Structure of a nephron