Physiology - Renal Difficult questions

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Physiology - Renal Difficult questions
2011-03-04 23:30:53

Difficult questions
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  1. roles of kidney
  2. osmolarity depends on?
    number not size of solute
  3. normal saline
    • 0.9g/dl
    • or
    • 9%
  4. non penetrating solutes
    • ethanol
    • urea
    • metabolised glucose (synthesized in cell)
  5. difference between osmolarity and tonicity
    • osmolarity= diffusion of water down is gradient
    • tonicity= movement of water inresponse to changes in osmolarity
  6. forces governing movement
    • across capillary walls:capillary pressure osmotic pressure, tissue pressure (starling forces)
    • across cell membrane: osmotic effects
  7. intrinsic control of GFR
    • myogenic: sensed by high BP stretching stretch receptors which result in vaso constriction of Afferent arterioles
    • tubuloglomerular feedback flow sensed by macula densa which gets paracrine hormones to constrict Afferent arterioles
  8. Extrinsic control of GFR
    • sympathetic innervation - reduces GFR by constricting Afferent arteriole
    • occurs during a hemmorage
  9. differences between dectecting GFR and RPF
    • GFR measured by: substance that is not secreted, filtered or reabsorbed (tested with mainly creatinine or insulin)
    • clearance: volume of filtered fluid with all solutes removed from it
    • RPF measured by: substance that is both filtered and secreted but not absorbed (measured by pah) (a protein)
    • total clearance: no agent remains in renal vein
  10. Filtration Forces
    • PROMOTED by: blood pressure
    • OPPOSED by: osmotic pressure (more proteins reabsorbed in blood here) and tubule pressure (fluid already in capsule)
  11. Renal Plasma Flow Calculations
    • RPFxP(pah)=U(pah)xV/t
    • or
    • RPF=[U(pah)xV/t] P(pah)
  12. Renal Blood Flow Calculations
    RBF =RPF/1-HTC (hematocrit)
  13. Calculating GFR
    filtration rate x Plasma conc = Urine conc x Urine Volumeaka (mass filtered) = (mass excreted)
  14. which side of the proximal tubule has micro villi
    luminal side
  15. Symport example
    Na/glucose co transport
  16. Antiport example
    Na/H co transport
  17. Secondary Active Transport Example
    Na gradient set up by Na/K ATPase (basolateral)
  18. solvent drag example
    sodium glucose linked transporter
  19. Organic Ion Secretion
    • organic ions (eg. penicillin, aspirin) are actively secreted into the filtrate
    • un-ionized substances first converted to ionized form in liver and then secreted
    • ionized substances remain in filtrate
  20. still have to do lecture 4
  21. what determines ECF osmolarity
  22. what regulates ECF volume
    • renin angiotensin and aldosterone
    • (RAA) System
  23. low A2 constricts the
    • efferent arteriole
    • increases GFR
  24. what creates new Na channels and Na/K ATPase
  25. what promotes natriuresis (Na excretion) and Na reabsorption from collecting duct
  26. lecture 6
  27. lecture 7 and 8