Flashcards in Acid-base homeostasis Deck (15):
What buffering systems exist within the human body?
Misc organic acids
What are the sites of acid-base metabolism?
What would cause a right shift of the O2-Hb dissociation curve?
Increased 2,3 diPG
Where is bicarb reclaimed and generated?
Where is the dominant site of lactate metabolism?
Where is the only site of urea synthesis?
Why does severe metabolic alkalosis occur in liver failure?
Liver can no longer metabolise NH4+ to urea. Build up of ammonia.
What are the compensatory mechanisms for acid/base disturbances?
Renal bicarbonate regeneration
Hepatic shift between urea synthesis and ammonia excretion
What are the mechanisms behind metabolic acidosis?
Increased H+ formation
Reduced renal H+ excretion, or Loss of bicarbonate
H+ increases, pCO2 decreases and pO2 increases (due to compensatory hyperventilation)
What is the mechanism behind metabolic alkalosis?
Generation of bicarb by gastric mucosa (e.g. vomiting), renal generation of HCO3- in hypokalaemia, administration of bicarb (e.g. antacid abuse)
H+ decreases, pCO2 increases and pO2 decreases as drive to breathe is depressed by loss of H+
What is the mechanism behind respiratory acidosis?
H+ + HCO3- -> H2CO3 -> CO2+ H2O
CO2 retention due to
1: inadequate ventilation
2: parenchymal lung disease
3: inadequate perfusionH+ increases, pCO2 increases and pO2 decreases
What is the mechanism behind respiratory alkalosis?
H+ + HCO3- -> H2CO3 -> CO2 + H2O
Increased CO2 excretion due to excessive ventilation producing alkalosisH+ decreases, pCO2 decreases (being blown off) and pO2 increases
What conditions may cause increased H+ formation?
ketoacidosis, diabetic or alcoholic
inherited organic acidoses
What are the two types of lactic acidosis?
type a shock
type b metabolic and toxic causes