[julie_hills]

Can somebody please explain how the body respiratory compensates for a metabolic acidosis. For example what is happening in the body in order to control the ph level. Linking in hydrogen ions etc..

thanks

[live_crow]

The compensatory mechanism is hyperventilation to reduce the arterial pCO2. Metabolic acidosis (reduced HCO3-) most commonly stimulates the central and peripheral chemoreceptors that control respiration, resulting in an increase in alveolar ventilation, which results in a compensatory respiratory alkalosis (excretion of CO2 = less carbonic acid).

[bill4745]

A patient in metabolic acidosis breathes faster, to get rid of CO2, which, if I remember correctly, (it's been a while!) forms acidic substances in the body.

[mandana]

I'll take a shot.

pH is maintained by buffer systems, let's talk about the bicarbonate buffer system.

CO2 + H2O <===> H2CO3 <===> H + HCO3

In metabolic acidosis, bicarb (HCO3) is decreased compared to the acid in the body. To compensate, rate and depth of respirations increase to eliminate extra CO2. Look at the above formula and you'll see how eliminating extra CO2 will bring the HCO3 level back into balance.

Hope that helps.

Amanda

[Dinith88]

Originally Posted by mandana

eliminating extra CO2 will bring the HCO3 level back into balance.

Thats mostly correct, however 'blowing-off' CO2 doesnt 'regulate' HCO3...rather it just lowers the CO2 (in an attempt to 'regulate' pH).

Think of it like this: the body's pH has to be within a certain range (7.35-7.45). When your body's in a metabolc acidosis (for whatever reason) your body will try and 'blow off' extra CO2 because in your blood-stream CO2 is an acid.

It's kinda simple really. If your body has too much 'acid' in it's bloodstream, it tries to get rid of some by hyperventilating.

....like bill said