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19 Cards in this Set
- Front
- Back
- 3rd side (hint)
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What is pKa equal to in terms of Ka (dissociation constant)
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pKa=-log[ka]
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What is a good buffer?
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buffers are most effective in controlling pH and binding H+ if the pH is near the pKa of their ionizing group
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Know how to find the best pH (concentration of H+) on a titration curve graph… pKa is the center of the curve, where 50% of the buffer species has a proton attached.
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What are two buffers seen in the physiology?
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bicarbonate and ammonia
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pH 7.4, with a corresponding [H+] = 40nm/l, is normal for blood plasma. What changes in [H+] and corresponding pH are life threatening?
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alkalosis: 20nm/l = 7.7… and acidosis: 100nm/l = 7.0… not 7.1-7.3 are clinically significant [50-80nm/l]
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Is Hb a buffer?
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yes, it's temporary reservoir for H+, but only inside the RBC
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Which direction does carbonic anhydrase work?
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both direction… formation of H2CO3 and formation of H20 +CO2
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What does the band 3 protein do?
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it is an anion exchanger Cl- for HC03
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where is bicarbonate produced?
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kidneys
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How are the lung important in maintaining pH balance in the body?
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H+ are excreted as the H in H2O
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Where do you find carbonic anhydrase?
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RBCs and Kidney
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Give the Henderson-Hasselbalch equation, only to show the effects of plasma HCO3- and pCO2 concentrations on pH.
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pH = 6.1 + log [HCO3-]÷(0.0301 X pCO20… such that a rise in HCO3- will cause an increase in pH and an increase in pCO2 will cause a drop…or any overall increase in the quotient will cause a rise in pH
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What does the liver do in resonsponse to low pH?
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reabsorb HCO3
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None
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What two general catagories cause repiratory acidosis?
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(a) U:An increase in blood pCO2, ORIGINS: COPD, chronic lung disease, lung removal, sedation, hypoventilation. (b) U: A decrease in [HCO3], ORIGINS: excess production of organic acids, loss of HCO3 via DIARRHEA.
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What two general catagories causes respiratory alkalosis?
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(a) U: A decrease in blood [CO2], ORIGINS: hyperventilation (light-headedness follows). (b) U: increase in blood bicarbonate, ORIGINS: vomiting gastric fluids, consuming large amounts of antacides, dehydration (reduced pressure for renal filtration)
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How do the kidneys compensate for alkalosis? For (a) decrease in pCO2 and (b) increase in blood [HCO3]
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(a) decrease in renal bicarb resorption and an increase in renal K+ secretion into the renal tubule (b) decrease in respiration to increase plasma [CO2]
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How do the kidneys compensate for acidosis? For (a) increase in blood CO2, (b) decrease in plasma [HCO3]
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(a) decrease in renal bicarb and increase in renal H+ secretion into the renal tubules. (b) increase respiration to clear CO2 from plasma.
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Based on lab tests, how can you diagnose organic acidosis?
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When the anion gap grows (normal is about 10
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What is the biochemical basis for diabetic ketoacidosis (or alcohol consumption)?
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In order to maintain an anion balance the cells will transport out a protein, i.e., ketoacid, but you can't pass it through the membrane with a charge, so a cation, i.e., K+ or Na+ will attach to the anion. However when the cell runs low on K+ it will steal a proton from a protein... once released from the cell it lowers the plasma pH.
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