Acid Base Regulation - Columbo Flashcards Preview

Biochemistry > Acid Base Regulation - Columbo > Flashcards

Flashcards in Acid Base Regulation - Columbo Deck (22):

Arrhenius definition of acids/bases

Acids increase H+ ion concentration in aqueous solutions, bases increase OH- in aqueous solutions


Bronsted-Lowry definition of acids/bases

Acids donate protons, while bases accept protons (but do not necessarily increase OH- concentration_


Lewis definition of acids/bases

Acids accept electron pairs, bases donate electron pairs


Most acids/bases we consider in a physiological context are weak as opposed to strong. Why is this important?

Our ability to keep our pH regulated is due to the buffering capacity of our body fluids; strong acids/bases would make it much more difficult to buffer because they completely disassociate in solution


Biological processes that can be affected by changes in pH

-protein folding and conformation
-ion currents
-ligand-receptor interactions
-muscle contraction
-cell proliferation


What is the condition that results from an overabundance of H+ ions in the blood?



What is the condition that results from a lowered H+ concentration in the blood?



what does pH describe about the relationship of conjugate base/acid in the blood?

the ratio between them, as opposed to the amount of each


3 ways H+ concentration in the blood serum is controlled

1) lungs can remove CO2
2) kidneys can remove H+, retain HCO3-
3) buffering resists pH change
*these are reversible in cases of alkalosis


What is a respiratory reaction of increased H+ ions (decrease in pH)?

-increase in alveolar ventilation


What is a respiratory reaction of decreased H+ ions (increase in pH)?

-respiratory depression and retention of CO2
-lowered O2 levels can stimulate respiration, so it has less of an impact


In terms of renal control of pH, is the retention of HCO3- or the excretion of H+ more important?

-retention of HCO3-
-the excretion of 1 HCO3- is the same as adding 1 H+
-HCO3- can bind a free H+ (acts as buffer), so retaining it will lower free H+


3 key buffer systems

1) bicarbonate - buffers extracellular fluid
2) phosphate - buffers intracellular fluid and kidney tubules
3) proteins - absorb free H+ ions in intracellular and extracellular environments (example is deoxy-hemoglobin in RBCs)


What is a buffer?

-a substance that is capable of absorbing or releasing H+ ions, helping solution resist pH change
-example: carbonic acid can disassociate to form 1 free H+ ion and bicarbonate, or the reverse can occur (we are either adding an H+ to lower pH, or absorbing an H+ to increase pH)


What is the Henderson-Hasselbalch equation?

pH = pKa + log [A-]/[HA]
-remember that the acid has more Hs
-if the ratio of [A-] to [HA] is equal, then pH = pKa


relative to the Henderson-Hasselbalch equation, when are buffers most effective?

pH = pKa + log [A-]/[HA]
-when pH = pKa
-aka when the ratio of [A-] to [HA] is equal


3 important regulators of intracellular pH

1) ion transporters
2) protein buffer system
3) phosphate buffer system


What can cause hypoventilation-induced acidosis?

*related to blood CO2 levels*
-obstructive lung diseases
-CNS trauma
-insufficient ventilation


What can cause hyperventilation-induced alkalosis?

*related to blood CO2 levels*


What can cause metabolic acidosis?

*related to blood HCO3- levels*
-renal insufficiency
-excessive lactic acid


What can cause metabolic alkalosis?

*related to blood HCO3- levels*
-excessive vomiting


What is a mixed acid-base disorder?

-when more than one simple disturbance in acid-base exists
-example: one disturbance can cause both acidosis (respiratory or metabolic) and alkalosis (respiratory or metabolic)