The nephron

Urine is produced in microscopic structures in the kidney called nephrons. Each kidney contains around a million nephrons.

Kidney nephron showing Bowman's capsule, the glomerulus, blood capillaries, loop of Henle, convoluted tubules and collecting duct.The structure of a nephron

The Bowman’s capsule (renal capsule):

  • surrounds a ball of capillaries called the glomerulus
  • the blood is put under high pressure
  • ultrafiltration of the blood happens, in which water, ions,glucose and other small molecules pass into the tubule (but not proteins or cells)

The first convoluted tubule (proximal convoluted tubule) is responsible for:

  • the selective reabsorption of glucose

The collecting duct is responsible for:

  • the selective reabsorption of water
  • sending urine to the ureter