The nephron

• What is the nephron?

  Microscopic filtering unit in kidneys
• How many nephrons are there in each kidney?

  Over one million
• What are the key stages involved in kidney function?

  • Filtration
  • Selective reabsorption
  • Formation of urine
• What is the Bowman’s capsule?

  Structure surrounding the capillary knot
• What does the Bowman’s capsule surround?

  A ball of capillaries called the capillary knot
• Why is high pressure created in the capillary knot?

  Due to the narrower diameter of the exiting capillary
• What is the result of the high pressure in the capillary knot?

  It leads to ultrafiltration
• What happens during ultrafiltration in the Bowman’s capsule?

  Small molecules pass into the capsule, large ones do not
• What small molecules pass from the capillary into the Bowman’s capsule?

  Water, salts, glucose, and other small molecules
• What happens in the tubule after filtration?

  Selective reabsorption of glucose, salts, and water occurs
• What role does the collecting duct play?

  Responsible for further water reabsorption
• Where does the collecting duct send urine?

  To the ureter