Urinary- Acid Base

Card Set Information

Urinary- Acid Base
2015-09-17 20:51:40
vetmed urinary

vetmed urinary
Show Answers:

  1. pH is based on the...
    ratio of HCO3 to PCO2
  2. Why is venous blood slightly more acidic than arterial blood?
    because of the carbon dioxide that forms HCO3 (carbonic acid)
  3. pH=
  4. What is the Hendersen-Hesselbach equation?
    pH= pK + log ([A-]/[HA])
  5. The velocity of a reaction is proportional to the product of the concentrations of the reactants.
    Law of Mass Action
  6. Chemical buffers work by...
    combining with acid or base to prevent changes in pH
  7. What are the 3 buffer systems of the body?
    chemical buffers (bicarb, phosphate, proteins), lungs, kidneys
  8. By what equation do the lungs buffer the blood?
    CO2 + H2O <--> H2CO3 <--> HCO3 + H+
  9. Buffers work best within ___________.
    range of their pK
  10. __________ is the most important extracellular buffer.
  11. ________ are important intracellular buffers, especially _______ in ________.
    Proteins; hemoglobin; blood cells
  12. __________ is an important intracellular urinary buffer.
  13. ___________ has a vast buffering capacity for chronic acidosis (not acute because it takes a long time).
    Bone carbonate
  14. No matter how many buffers are present, there is only one [H+] and pH.
    isohydric principal
  15. How does acidosis affect CO2 + H2O <--> H2CO3 <--> HCO3 + H+ ?
    shift the equation to the right, lungs respond by increasing ventilation to get rid of CO2 (hyperventilation causes alkalosis)
  16. How does poor ventilation affect CO2 + H2O <--> H2CO3 <--> HCO3 + H+?
    drive the equation to the left, creating acidosis (hypoventilation causes acidosis)
  17. The kidneys must...
    reabsorb all filtered bicarb and secrete H+
  18. Bicarbonate is ________ at the glomerulus.
    freely filtered
  19. For each bicarbonate that is reabsorbed, it requires...
    that a H+ ion be secreted.
  20. With acidosis, the kidneys reabsorb all the __________ and make new to enter the blood, secreting ______ in the process.
    bicarb; H+
  21. With alkalosis, the kidneys do not ______________, allowing some to be ___________.
    reabsorb all the bicarb; excreted in the urine
  22. 85% of the bicarbonate is reabsorbed in the __________.
    proximal tubule
  23. Where are the 2 sites of H+ secretion, and how does it occur at each location?
    proximal tubule (secondary active transport), distal tubule (primary active transport)
  24. H+ is secreted in the ultrafiltrate in the proximal tubule by ___________ with a __________, which is fueled by the ___________ creating a gradient favorable for __________.
    secondary active transport; sodium countertransporter; Na+K+ATPase pump; sodium entering the cell
  25. Once H+ is secreted into the ultrafiltrate in the proximal tubule, it combines with ________, which was ___________.
    HCO3-; filtered at the glomerulus
  26. H2CO3 in the ultrafiltrate dissociates into __________, a reaction that is catalyzed by ____________.
    CO2 and H2O; carbonic anhydrase
  27. CO2 from H2CO3 diffuses into the __________, where it ___________ with _______ to make ________, which dissociates to __________; the _________ is reabsorbed into the __________.
    tubular cell; recombines H2O; H2CO3; H+ and HCO3-; HCO3-; blood stream
  28. H+ is secreted in the distal tubule by __________ through __________ in __________ cells.
    primary active transport; H+ATPase pump; intercalated type A
  29. H+ that is secreted to the lumen of the distal tubule combines with ___________; intracellular bicarb is reabsorbed with a ____________; each filtered HCO3-...
    bicarb; Cl exchanger; buffers a secreted H+ and a different HCO3- is reabsorbed.
  30. Primary active transport of H+ in necessary for ____________; this occurs in the _____________.
    finely-tuned acid-base balance; distal and collecting tubules
  31. Why do we need buffers in the urine?
    because only a limited amount of H+ can be excreted in the urine before it gets so acidic that it is damaging
  32. NaHPO4 is filtered at the __________, and there is usually a ____________ of it; secreted H+ is buffered by it, yielding ________.
    glomerulus; net secretion; NaH2PO4
  33. Why is phosphate an excellent urinary buffer?
    b/c its pK is the same as urine pH
  34. The amount of base needed to get a 24-hr urine sample to a pH of 7.4 is __________; equated with _________.
    titratable acidity; phosphate
  35. Glutamine is converted to __(2)__ in the proximal tubule.
    ammonium and bicarbonate
  36. Ammonium is secreted into the ultrafiltrate using the __________.
    Na+H+ countertransporter
  37. For ammonia buffering in the collecting tubule, ammonia (NH3) ________ into the ultrafiltrate; it buffers a H+, forming ________, which can't diffuse back because it is __________; therefore, it is...
    diffuses; ammonium (NH4+); polar; trapped in the ultrafiltrate to be excreted
  38. Describe ammonia recycling.
    NH3 diffuses into lumen--> picks up H+ and becomes NH4+--> moves down LoH--> in a.LoH, jumps on Na+K+2Cl- pump (in K+ spot)--> get reabsorbed--> dissociates to release H+--> NH3 diffuses back into lumen--> repeat
  39. Stimuli for increasing H+ secretion by the tubules in acidosis:
    increase in PCO4 in extracellular fluid (increases formation of H+ in cells), an increase in H+ concs in extracellular fluid
  40. All filtered bicarbonate is reabsorbed by ____________ into the ultrafiltrate, which binds ___________.
    secreting H+; HCO3-
  41. To excrete acid that is consumed/produced, H+ is...
    secreted into the ultrafiltrate in excess of that needed to resorb bicarbonate.