Acid-Base (1) Flashcards
What is the major buffering mechanism in interstitial fluid?
Carbonic acid - Bicarbonate
What are the major buffering mechanisms in blood?
Bicarbonate, Protein, Haemoglobin.
What are the major buffering mechanisms in intracellular fluid?
Proteins, Phosphate.
What are the major buffering mechanisms in urine? What is an adaptive buffering mechanism in urine, used in chronic acidosis?
Major ones: Bicarbonate, Phosphate.
Adaptive: Ammonium.
What is the difference in the buffering capacities of haemoglobin and plasma proteins?
Hb has 6 times the buffering capacity of the plasma proteins (due to its abundance and its long histadine residues).
Define the “anion gap”.
The anion gap refers to the difference between the concentration of cations (except for Na+) and the concentration of anions (except for Cl- and HCO3-).
What does the anion gap mostly consist of?
HPO4, SO4, organic acids.
Name as many conditions as you can that will cause a raised anion gap metabolic acidosis.
DKA, Lactic acidosis, Uraemia, Rhabdomyolysis, CRF, Aspirin overdose.
Name as many conditions as you can that will cause a normal anion gap metabolic acidosis.
These tend to be conditions that cause acidosis by increased bicarbonate losses.
Diarrhoea, Renal Tubular Acidosis, Hyperchloraemic acidosis.
What effect does a change in protein concentration have on the anion gap?
Raised protein will increase the anion gap.
Hypoalbuminaemia will decrease the anion gap.
What is pKa?
The pKa of a drug is the pH at which that drug is 50% ionized and 50% unionized. If the drug is an acid, it will become more dissociated (ionized) at a pH above its pKa. If the drug is a base, it will become more dissociated (ionized) at a pH below it’s pKa.
What is the Henderson Hasselbach equation?
pH = pKa + log([base]/[acid])
