CO2 Transport

Watch Video
  • Topic Anchor: CO2 Transport
    • Gaseous CO2 in RBCs is converted into carbonic acid and bicarbonate to allow water-soluble transport in blood
      • CO2 + H2O <--> H2CO3 <--> HCO3— + H+
      • CO2 mainly carried as bicarbonate ion in blood
      • Catalyzed by carbonic anhydrase
      • pCO2 drives CO2 transport
        • In tissues
          • High pCO2 generated by respiration of tissues
            • drives reaction forward
          • Conversion of CO2 → bicarbonate
            • Bicarbonate diffuses into plasma, allowing reaction to continue
        • In lungs
          • Low pCO2 due to exhalation
            • drives the reaction backward
          • Conversion of bicarbonate → CO2
            • Bicarbonate diffuses from plasma into RBC to supply this reaction
    • Used to buffer pH of blood
      • When blood is too acidic, reverse reaction is favored to increase pH
      • When blood is too basic, forward reaction is favored to decrease pH