acid base Flashcards
what is the principal extracellular buff system
carbonic acid/ bicarbonate (H2CO3/HCO3) system
what are examples of 3 physiologic buffers
- plasma proteins
- hemoglobin
- phosphate
what regulates bicarbonate in carboinic acid/bicarb buffer system
kidneys
why is the carbonic acid/bicarb buffer the most important buffer system in the body
- more bicarbonate in the ECF than any other buff
- unlimited supply of CO2
- defree of ECF acidity can be regulated by changing HCO3- and/ pCO2
what is the respiratory component of carbonic acid/bicarb buffer
carbonic acid
what is the metabolic component of the carbonic acid/bicarb buffer system
bicarbonate (HCO3-)
what is the respiratory component of the carbonic acid/bicarb buffer system equation
CO2 + H2O
how is bircarbonate reported clinically in an electrolyte panel?
serum CO2
what sense changes in pCO2 and H+ concentrations and modulate the control of breathing?
medullary chemoreceptors in the brain
what is regulated renally in the carbonic acid/bicarb buffer system?
- excretion of acid (H+)
- reabsorption of filtered HCO3-
- regeneration of bicarbonate
how much bicarb is delivered to the nephron daily
~4500 mEq HCO3-
where is bicarbonate freely filtered
glomerulus
where does 90% of bicarbonate reabsorption occur?
proximal tubule
what catalyzes the reabsorption of carbonic anhydrase
carbonic anhydrase
where doe remaining H+ secretion occur after having been reabsorbed via carbonic anhydrase
distal tubule
If your primary disorder is respiratory, compensation will take place with what?
kidneys compensate by adjusting bicarb elimination
If your primary disorder is metabolic, compensation will take place with what?
lungs will compensate by adjusting CO2 elimination
what are the 3 major components of assessing acid base statue
- blood gas
- serum electrolytes
- medication and medical history
what are serum electrolytes useful for when assessing acid base status
delineating respiratory vs. metabolic disorders
what is the most important diagnositic test for acid bace status
arterial blood gas
what is caused by decreased serum HCO3- concentration, resulting in decreased pH
metabolic acidosis
what are 3 things that can result in metabolic acidosis
- diarrhea = increased elimination of HCO3- stores
- renal failure = decreased elimination of org. acids
- lactic acid = increased production of organic acids
what occurs from accumulation of anions that result from consumption of HCO3 by endogenous organic acids or toxin ingestion
increased anion gap
what are 4 common causes of elevated anion gaps
- renal failure
- ketoacidosis
- lactic acidosis
- intoxications
