Quick question of buffering action of bicarbonate in acidosis?

  • #1
663
3

Main Question or Discussion Point

Hello everyone,

Bicarbonate concentration reduces in acidosis. My question is where actually does this buffering take place and why it reduces?Do Hydrogen ions move into cells (like red blood cells), where they are buffered by bicarbonate. I'm talking about this reaction that occurs inside cells

CO2 + H20 <-> H2CO3<-> H+ + HCO3-

If this is the case why does bicarbonate in extracellular fluid decrease. Is it because the reaction I mentioned above occurs, in reverse direction and there is less efflux of bicarbonate from cells. Also does bicarbonate from extracellular fluid move into cells, to carry out this reaction.

or

Are hydrogen ions buffered in extracellular fluid by bicarbonate. Does the same reaction occur in extracellular fluid as well.

Thank you :smile:
 

Answers and Replies

  • #2
bobze
Science Advisor
Gold Member
647
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Hello everyone,

Bicarbonate concentration reduces in acidosis. My question is where actually does this buffering take place and why it reduces?Do Hydrogen ions move into cells (like red blood cells), where they are buffered by bicarbonate. I'm talking about this reaction that occurs inside cells

CO2 + H20 <-> H2CO3<-> H+ + HCO3-

If this is the case why does bicarbonate in extracellular fluid decrease. Is it because the reaction I mentioned above occurs, in reverse direction and there is less efflux of bicarbonate from cells. Also does bicarbonate from extracellular fluid move into cells, to carry out this reaction.

or

Are hydrogen ions buffered in extracellular fluid by bicarbonate. Does the same reaction occur in extracellular fluid as well.

Thank you :smile:

Draw a little picture of how this reaction happens across RBC membranes. Then think like Le Châtelier did.
 
  • #3
663
3
Draw a little picture of how this reaction happens across RBC membranes. Then think like Le Châtelier did.
Hello Bobze. I understand how reaction would go to left and buffer but that is not what I'm asking. Is this happening in extracellular fluid or intracellular fluid? I think you read the topic in a hurry.
 
  • #4
2,123
79
Hello Bobze. I understand how reaction would go to left and buffer but that is not what I'm asking. Is this happening in extracellular fluid or intracellular fluid? I think you read the topic in a hurry.
Both, although the intracellular processes are less well understood.

http://www.anaesthesiamcq.com/AcidBaseBook/ab2_6.php

Proteins and phosphates play a much larger role in buffering in the ICF than in the ECF but bicarbonate buffering also occurs in the ICF.

Secondly, metabolic pathways in the cell can adjust the production of acids to compensate for changes in intracellular pH.

Thirdly, mitochondria and lysosomes can sequester or release H ions by mechanisms that are not fully understood.
 
Last edited:

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