The kidney Biology unit 3

HideShow resource information
View mindmap
  • The Kidney
    • Ultrafiltration
      • Filtration under pressure
      • Glomerular filtration rate= the rate at which fluid passes from blood to glomerular capillaries into Bowmans capsule
      • Separates small soluble molecules from the blood plasma in Bowmans Capsule
      • lies between blood and nephron and filters solutes
      • Selective reabsorption
        • Useful products are reabsorbed (GLUCOSE, WATER, SALTS) in the proximal convoluted tubule.
        • Remaining WATER taken in by collecting duct
      • Basement membrane of capillary is a selective barrier
      • Hydrostatic Pressure forces molecules through filter, amplified by the narrowness
    • Structure
      • URETER carries urine from kidney to bladder
      • Serves proximal and distal convoluted tubules
      • Blood recieved by renal artery and sent to renal vein
      • Afferent arteriole- >glomerulus->capilaries
      • Vasa recta along loop of henle
      • nephrons have close association with blood vessels
    • ADH
      • Decreased ADH makes walls less permeable to absorb less water
      • Affects permeability of collecting ducts and distal convoluted tubules
      • Increased ADH makes wallks more permeable ro reabsorb more water
    • Homeostasis
      • Maintenance of a constant environment
      • receptor detects deviation
      • set point is desired norm
      • After correction detector turns off
      • Coordinator communicate with effector to correct deviation
    • Excretory products
      • Mammals excrete urea, less toxic than ammonia = can be stored for short time=  needs energy
      • Birds and insects excrete uric acid, insoluble, needs high energy but little water, useful when water is scarce
      • Fish produce ammonia, highly soluble so diffuse out across gills and dilute to non-toxic levels
    • Loop of henle
      • loop is most concentrated at the bottom
        • Counter current multiplier
          • Collecting duct fluid runs back down the medulla through the low water potential causing more water to pass out into the vasa recta
        • Maximum concentration is built up inside and outside the apex of the loop
          • Counter current multiplier
            • Collecting duct fluid runs back down the medulla through the low water potential causing more water to pass out into the vasa recta
          • High concentration of salts in medulla causes osmotic flow of water out of ducts concentrating urine so hypertonic to blood
      • Ascending limb walls impermeable to water actively transporting Na+ and Cl- out into tissue fluid between the 2 limbs to lower the water potential
        • Fluid flows down and water passes out by osmosis while Na+ and Cl+ diffuse in losing lots of water
    • Osmoreceptor= detect changes in solute concentration in blood to regulate osmoregulation on a negative feedback principle.
    • Desert Mammals
      • Live on metabolic water produced from oxidising food reserves
      • Longer loops of henle for greater water potential gradient
      • Live undeground as cooler  = reduce water loss by evaporation
      • reabsorb more water
    • RECAP
      • Decreased conc
        • Hypothalmus
          • Increased conc
          • Pituitary Gland
            • Decreased conc
              • Hypothalmus
                • Increased conc
                • Pituitary Gland
                  • ADH
                    • More ADH
                    • Less ADH
                    • Wall of collecting duct
                      • Less ADH
                      • More ADH
                      • More permeable
                        • ADH effect
                          • decreased
                            • concentration of urine
                              • Increased
                                • volume of urine
                                  • normal
                              • decreased
                                • volume of urine
                                  • normal
                          • increased
                            • concentration of urine
                              • Increased
                                • decreased
                          • Less permeable
                            • ADH effect
                              • decreased
                                • increased
                    • ADH
                      • Wall of collecting duct
                        • More permeable
                          • Less permeable

              Comments

              No comments have yet been made

              Similar Biology resources:

              See all Biology resources »See all The kidney resources »