The KIDNEY

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  • Created by: Steff06
  • Created on: 28-02-16 09:45
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  • The Kidney
    • Role of the kidney = To REMOVE WASTE PRODUCTS from the blood and to PRODUCE URINE.
    • The urine passes out of the kidney down the URETER to the BLADDER where it c an be stored before release.
    • The OUTER region is called the CORTEX. The INNER region is called the MEDULLA. In the CENTRE is the PELVIS which leads into the URETER.
    • The NEPHRON:
      • Nephrons are tiny TUBULES. Each nephron starts in the CORTEX. In the cortex the CAPILLARIES form a KNOT known as the GLOMERULUS.
      • This is surrounded by a cup-shaped structure known as the BOWMAN'S CAPSULE. Fluid from the blood is pushed into the Bowman's capsule by ULTRAFILTRATION.
    • The nephron is divided into 4 parts. The PROXIMAL CONVOLUTED TUBULE, DISTAL CONVOLUTED TUBULE, LOOP OF HENLE and the COLLECTING DUCT.
    • As the fluid moves along the nephron, its composition is altered. This is achieved by SELECTIVE REABSORPTION.
      • Substances are reabsorbed back into the TISSUE FLUID and blood CAPILLARIES. Final product in the COLLECTING DUCT is URINE.
    • Composition change:
      • Reabsorbs ALL SUGARS, MOST SALTS and SOME WATER. 85% of fluid is reabsorbed in the PCT.
      • In DESCENDING LIMB of the LOOP OF HENLE, water potential is DECREASED by addition of SALTS and removal of water.
        • Water POTENTIAL INCREASED in ASCENDING LIMB of LOH as SALTS are REMOVED by ACTIVE TRANSPORT.
          • Water potential DECREASED in COLLECTING DUCT by REMOVAL of WATER. Ensures URINE has a LOW water potential.

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