J1iii: An Open System

  • The CO2 / HCO3– buffer system is considered an open system because its components (CO2 + HCO3–) are regulated independently
  • A buffer cannot fix an acid-base imbalance
  • It can only ‘buy time’ for the body to correct the acid-base disturbance
    • CO2 → lungs → exhaled
    • HCO3– → kidneys → reabsorbed
  • They are handled independently
  • CO2 cannot be converted to a fixed acid & excreted by kidneys
  • ↑CO2 requires ↑Mv to correct acid-base imbalance
  • Likewise, fixed acid cannot be converted to CO2 & exhaled
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