Carbon Dioxide

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Introduction

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Carbon dioxide is pretty important.

 

Arterial Blood

 

Transport of CO₂

 

Following cellular respiration and production in the TCA cycle, CO₂ leaves the cell rapidly down its concentration gradient. Once in the blood, most (89%) of incremental CO₂ travels in RBCs:

• 64% as HCO₃
• 21% as carbamino compounds with Hgb
• 4% as dissolved CO₂

11% travels in plasma:

• 6% as dissolved CO₂
• 5% as HCO₃

Therefore, in total,

• 69% as HCO₃
• 21% as carbamino compounds with Hgb
• 10% as dissolved CO₂

CO₂association with Hgb stabilizes the taut formation of Hgb, decreasing oxygen affinity ans shifting the curve to the right.

 

Factors Affecting TCO₂ in the blood

• pCO_2: increases transport in all forms
• plasma protein concentration: increases HCO₃
• plasma pH: increases HCO₃ formation, carbamino Hgb
• pO₂: decreases carbamino Hgb

 

 

 

Resources and References

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