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6. Why is the DCT and CD hypertonic in concentrated urine?

  • Some solute reabsorption from DCT and CD, but no ADH release, no aquaporin insertion, therefore no H2O reabsorption
  • ADH release aquaporin insertion, therefore H2O reabsorption
  • Loss of H2O reabsorption into the vasa recta, no solute reabsorption
  • Loss of solute into the interstitum and some into the vasa recta, no H2O reabsorption
  • Similar H2O and solute reabsorption into the peritubular capillaries

7. What is the urine volume with maximal ADH?

  • 300-400ml/day
  • 25L/day

8. Why is the ascending LoH hypotonic?

  • ADH release aquaporin insertion, therefore H2O reabsorption
  • Loss of solute into the interstitum and some into the vasa recta, no H2O reabsorption
  • Loss of H2O reabsorption into the vasa recta, no solute reabsorption
  • Similar H2O and solute reabsorption into the peritubular capillaries
  • Some solute reabsorption from DCT and CD, but no ADH release, no aquaporin insertion, therefore no H2O reabsorption

9. What value is it for the body fluids to become hyper-osmolar?

  • > 285mosm/Kg H2O
  • < 285mosm/Kg H2O
  • = 285mosm/Kg H2O
  • not 285mosm/Kg H2O

10. What is the urine osmolality with maximal ADH?

  • 1400mOsm/KgH2O- Same as the internal osmolality of the deepest medulla or close to the pailla
  • 60 mOsm/KgH2O- Same as the filtrate osmolality before it gets to the collecting ducts

11. What environment is the filtrate at the end of the ascending LoH

  • Hypotonic
  • Isotonic
  • Hypertonic

12. What is false about dehydration?

  • Hypernatremia is the real problem
  • Small volume of a concentrated urine as high as 1200 mOsm/KgH2O
  • Increase in osmolality of extracellular fluid
  • Increase in ADH release- aquaporin insertion to facilitate H2O reabsorption from DCT and CD

13. What environment is the filtrate at the end of the descending LoH

  • Hypotonic
  • Hypertonic
  • Isotonic

14. What will happen if there is insufficient H20 ?

  • small volume of dilute urine
  • large volume of dilute urine
  • small volume of concentrated urine
  • large volume of concentrated urine

15. What environment is the filtrate at the DCT and collecting duct to produce dilute urine

  • Isotonic
  • Hypotonic
  • Hypertonic

16. What environment is the filtrate at the end of the proximal convoluted tubules?

  • Isotonic
  • Hypertonic
  • Hypotonic

17. Does the amount waste products change with insufficient H20?

  • No, you are still producing 600mOsm of waste solutes that must be removed by the kidneys
  • Yes, you produce less that 600mOsm of waste solutes, which would have to removed by the kidneys

18. Why is the PCT isotonic?

  • Some solute reabsorption from DCT and CD, but no ADH release, no aquaporin insertion, therefore no H2O reabsorption
  • Loss of H2O reabsorption into the vasa recta, no solute reabsorption
  • ADH release aquaporin insertion, therefore H2O reabsorption
  • Similar H2O and solute reabsorption into the peritubular capillaries
  • Loss of solute into the interstitum and some into the vasa recta, no H2O reabsorption

19. Why is the descending LoH hypertonic?

  • ADH release aquaporin insertion, therefore H2O reabsorption
  • Loss of H2O reabsorption into the vasa recta, no solute reabsorption
  • Similar H2O and solute reabsorption into the peritubular capillaries
  • Loss of solute into the interstitum and some into the vasa recta, no H2O reabsorption
  • Some solute reabsorption from DCT and CD, but no ADH release, no aquaporin insertion, therefore no H2O reabsorption

20. What is the urine osmolality with no ADH?

  • 60 mOsm/KgH2O- Same as the filtrate osmolality before it gets to the collecting ducts
  • 1400mOsm/KgH2O- Same as the internal osmolality of the deepest medulla or close to the pailla