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24 Cards in this Set
- Front
- Back
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What is the normal range of blood pH in mammals?
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7.4
<7.35 - acidemia >7.45 alkalemia |
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What happens to the CNS if there is acidemia and alkalemia?
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Acidemia - depression, coma
Alkalemia - hyperactivity, tetany of respiratory muscle |
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Is the dihydrogen phosphate or the monohydrogen phosphate the acid form of phosphate?
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Dihydrogen
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Name 4 buffers of pH in the blood
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Bicarbonate
Phosphate Proteins Histidines (in RBCs) |
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How do buffers work?
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They either release or accept protons
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How does a buffer operate if the blood is acidic?
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Accepts proton
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What is the main difference between carbonic and lactic acid?
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Carbonic is volatile
Lactic is not |
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Which parts of the body deal with non-volatile and volatile acids?
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Lungs - volatile
Kidneys - non-volatile |
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How does the body maintain the pH of 7.4 in relation to bicarbonate and carbonic acid?
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Depends on the ratio of bicarbonate to carbonic acid
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What is the relation of pCO2 and pH?
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Can work out concentration of carbonic acid in blood to work out pH
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How is bicarbonate a perfect buffer in the lungs?
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Carbon dioxide produced in body makes blood too acidic, some of this carbonic acid is "blown off" in the lungs and increases the buffer to 7.4
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When is bicarbonate not a perfect buffer?
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This happens because the lungs cannot change the bicarbonate in the blood, only the carbonic acid component. So if bicarbonate is lowered in blood bla bla
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Why can bicarbonate buffer far from its pK of 6.1?
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Because the volatile component of carbonic acid, CO2, can be blown off in the lungs
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Where in the nephron is bicarbonate absorbed?
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In the proximal tubule
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Describe the reabsorption of bicarbonate in the proximal tubule
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Bicarbonate passes freely through glomerulus
Bicarbonate is protonated by H ion from Na/H antiporter on epithelial cell to H2CO3 Carbonic acid is dehydrated to CO2 and H2O by luminal carbonic anhydrase Carbon dioxide diffuses into cell CO2 and H2O hydrated to bicarbonate + proton by cytoplasmic carbonic anhydrase (isozyme) |
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What enables the Na/H antiporter to provide proton to bicarbonate?
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Sodium potassium pump - creates low sodium in cell
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How does the kidney produce bicarbonate into the blood?
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CO2 used to create bicarbonate + proton
Bicarbonate released into blood stream Proton added to phosphate to dihydrogen phosphate which is used to buffer the urine |
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What enables the phosphate buffering?
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Na K pump
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What happens to the dihydrogen phosphate formed?
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Either taken into blood
Or excreted in urine |
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What occurs when non-volatile acid production is too high for the kidney to cope with?
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Instead of phosphate buffering ammonia is used
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Where does the ammonia arise from?
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Glutamine - amino acid - dissociating into glutamate and ammonia
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How does ammonia buffer the urine?
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Ammonia binds with the excreted proton that could not bind to phosphate
Also bicarbonate released into blood |
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DRIVEN BY
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SODIUM POTASSIUM PUMP
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Which line of the fraction is affected by which organ?
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Top line - kidney - non-volatile acids
Bottom line - lungs - CO2 |
