34: Acid/base regulation of Lung - Wilson Flashcards
major buffer system operating in the blood
bicarbonate buffer system
H-H equation
pH = pKa + log A- / HA
simplified H-H equation
pH = 6.1 + log HCO3- / 0.03 x PCO2
the body is an open system … what does that mean?
lungs and kidney act independently of each other to regulate PCO2 and HCO3
bicarbonate consumed via buffering reactions, lungs compensate by …
increasing ventilation and lowering CO2 –> change in PH is minimized
hypoventilation –>
increased PCO2, increased H2CO3 and decreased pH –> respiratory acidosis
hyperventilation –>
decreased PCO2, decreased H2CO3 and increased pH –> respiratory alkalosis
graphical representation of the bicarbonate buffer system
look at slide 15 and slide 16
respiratory compensation regulates …
PCO2 with hypo or hyperventilation
rapid - hours change
renal compensation regulates…
HCO3 concentration and H+ excretion
slow - days change
changes in metabolic acidosis
- increased H buffered by consuming bicarbonate
- body compensates by increasing ventilation (decreasing PCO2)
- pH increases
changes in respiratory acidosis
- hypoventilation causes increase in PCO2
- increases bicarbonate by kidney
changes in respiratory alkalosis
- hyperventilation causes a decrease in PCO2 and increases pH
- kidneys excrete HCO3 to return pH to normal
changes in metabolic alkalosis
- bicarbonate is increased
- body responds by hypoventilation to increase PCO2
- kidney compensates by secretion of HCO3
drowning, COPD, asthma attack would lead to…
respiratory acidosis … restricted ventilation increases PCO2 and decreases pH
