The Kidney

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  • Created by: khodnett
  • Created on: 08-02-16 11:51
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  • The kidney
    • homeostasis
      • maintenance of a constant environment
      • set point is desired norm
      • receptor detects deviation
      • coordinator communicates with effector to correct deviation
      • detector turns off after correction
    • structure
      • blood received by renal artery and sent to renal vein
      • ureter carries urine from kidney to bladder
      • nephrons have close association with blood vessels
      • afferent arteriole ->glomerulus-> capillaries
      • serves proximal and distal convoluted tubules
      • vasa recta along loop of henle
    • ultra filtration
      • filtration under pressure
      • separates small soluble molecules from blood plasma in bowmans capsule
      • glomerular filtration rate is the rate at which fluid passes from blood to glomerular capillaries into bowmans capsule
      • basement membrane of capillary is a selective barrier
      • lies between blood and nephron and filters solutes
      • hydrostatic pressure forces molecules through filter, amplified by the narrowness
      • Selective reabsorption
        • useful products are reabsorbed such as glucose and water and salts in the proximal convoluted tubule
        • remaining water is taken in by collecting duct
    • loop of henle
      • high conc 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
      • descending limb walls are permeable to water Na+ and Cl-
      • fluid flows down and water passes out by osmosis while Na+ and Cl+ diffuse in losing lots of water
      • loop is most concentrated at the bottom
      • counter current multiplier
        • maximum concentration is built up inside and outside the apex of the loop
        • collecting duct fluid runs back down to medulla through the low water potential causing more water to pass out into the vasa recta
    • osmoreceptors
      • osmoreceptors detect changes in solute concentration in blood to regulate osmoregulation on a negative feedback principle
    • ADH
      • affects permeability of collecting ducts and distal convoluted tubules
      • increased ADH makes walls more permeable to reabsorb more water
      • decreased ADH makes walls less permeable to absorb less water
    • excretory products
      • fish produce ammonia, highly soluble so diffuse out across gills and dilute to non toxic levels
      • birds and insects excrete uric acid, insoluble, needs high energy but little water, useful when water is scarce
      • mammals excrete urea, less toxic than ammonia can be stored for short time needs energy
    • desert  mammals
      • live on metabolic water produced from oxidising food reserves
      • live underground as cooler to reduce water loss by evaporation
      • longer loops of henle for greater water potential gradient
      • reabsorb more water
  • hypothalmus
    • pituitary gland
      • ADH
        • wall of collecting duct
          • ADH effect
            • concentration of urine
              • volume of urine
                • normal
              • increased
                • volume of urine
                  • normal
              • decreased
              • decreased
                • concentration of urine
                  • increased
                    • decreased
                  • increased
                  • more permeable
                    • ADH effect
                      • decreased
                        • increased
                      • less permeable
                      • less adh
                        • wall of collecting duct
                          • more permeable
                            • less permeable
                          • more adh
                        • increased conc
                          • pituitary gland
                            • ADH
                              • less adh
                                • more adh
                            • decreased conc

                            Comments

                            megantiffin

                            this is well good :) 

                            Ephphatha

                            yup! thanx a lot!

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