Nephron structure

• nephron = a functional unit of the kidneys

  A) bowman's capsule

  B) arteriole to capillary knot

  C) arteriole from capillary knot

  D) filtrate

  E) tubule

  F) network of capillaries

  G) to the bladder

  H) collecting duct

  I) cortex

  J) medulla

  K) capillary knot

  
• change in diameter of blood vessel as it gets narrower in capillary knot -> makes pressure in capillary knot very high -> ultrafiltration
• small molecules filtered under pressure through capillary knot into Bowman's capsule
• water, urea, glucose and salts filtered
• protein and blood cells are too big to pass through capillary wall
• selective reabsorption = ALL glucose, some salts, most of the water
• where does selective reabsorption take place?

  in the tubule (so that useful molecules needed by body go back to blood)
• urine = mixture of urea, water and salt
• urine travels from collecting duct to ureter to bladder where it is stored
• blood should never pass through the kidney and be present in urine
• protein/glucose in urine = kidney failure/diabetes