Acid Base disturbances - roles of the cardiorespiratory and renal systems Flashcards
How is bicarbonate transported in the blood?
Either dissolved in the blood
Bound in the form of carbamino compounds
How are H+ ions buffered in the blood?
Bound to plasma proteins
Bound to haemoglobin
In the CO2/HCO3 system
Why is the HCO3 buffer not the best chemical buffer?
Since buffers work at their pKa (6.1 for HCO3) and this is far away from physiological pH of 7.4
What are the physiological importance of the CO2/HCO3 buffer?
In relatively high concentrations
Metabolism adds more CO2 to the system
Both components of the system can be tightly regulated
What is the most important factor about the blood pH?
The ratio between CO2 and HCO3
What happens if the ratio of CO2/HCO3 is >20?
Increase pH leading to alkalosis
What happens if the ratio of CO2/HCO3 is <20?
Decrease pH leading to acidosis
What regulates levels of CO2 and HCO3?
CO2 regulated by the lungs
HCO3 regulated by the kidneys
What is a respiratory disturbance?
Change in pH due to changes in PCO2
What is a metabolic disturbance?
Change in pH due to a change in HCO3 concentration
What is the concept of disturbance compensation vs correction?
A disturbance is compensated (pH returned towards normal) by the other system
Condition is only corrected when the correct pH and correct ratio is once again achieved.
What compensates a respiratory disturbance?
The kidneys
What compensates a metabolic disturbance?
The lungs
On a Davenport diagram what would each 4 quadrants mean?
Top left - Respiratory Acidosis
Bottom Left - metabolic acidosis
Top right - Metabolic alkalosis
Bottom Right - Respiratory alkalosis
What does transport of CO2 involve?
The production of H+ ions
