Acid Base 1 Flashcards
Definition of balance and steady state - difference between the two, and an example of divergence
Balance - in = out
Steady state - level of substance doesn’t change with time
difference is steady state can be achieved by shunting volume elsewhere; e.g. protons can be sent to the bone to keep them out of the ECF
Acidic amino acids ingested will increase what?
base load (as they take up protons in the body) vice versa for basic amino acids
Sulfur containing amino acids (M & C) present what kind of load?
acid load
Possible fates of non-volatile amino acids
Low enough pK will yield an acid
Metabolizable anions (like lactate or ketoanions) will have their proton consumed
Non-metabolizable anions (like oxalate or sulfate) leave their proton for the body to handle
Note: it is possible that the metabolizable anion (ketoanion or lactate) could be excreted before it is metabolized, resulting in the proton not being metabolized and therefore there would be a net acid gain in the body (acid load)
Alkali consumption and lemon and orange juice
Lemon juice is made up of citric acid while orange juice is potassium citrate;
Citric acid produces no acid-base change while potassium citrate produces 3 base equivalents (citrate is -3)
Response to an acid/base load
Buffer
Pulmonary response
Renal response
Four facts to know about buffers:
1) pK and concentration
2) distribution (ICF, ECF, etc…)
3) bicarb. vs. non-bicarb.
4) open vs. closed
Where do you find buffers for acid loads?
in the ICF, the ECF has buffers for alkali loads
Bicarbonate vs. non-bicarbonate
bicarbonate buffers are found mostly in the ECF, and are effective because with the removal of CO2, formation of carbonic acid is favorable
why is bicarb/carbonic acid/CO2 buffer good, even though its pK is ~4?
because it is an open buffer system, and the CO2 and carbonic acid concentrations stay the same, regardless of acid input. Only bicarb concentration changes
respiratory compensation occurs via what mechanism?
assuming that the concentration of bicarbonate were affected (up or down) then the lungs can respond by increasing or decreasing the pCO2 to counter the change from the concentration difference.
renal compensation occurs how?
hydrogen ions or bicarbonate are excreted into the urine. the opposite ion is then found in greater relative concentration
two ways to get acid out of balance?
dysequilibrium - take in too much acid
lose organic ion - if the body excretes the organic ion before it can be metabolized, then the hydrogen ion balancing reaction will not take place
