PH & BUFFERING-ORGAN SYSTEMS

SUMMARY

1. Respiratory system: controls pCO₂ through alterations in alveolar ventilation. CO₂ indirectly stimulates the central chemoreceptors of the medulla through the generation of H⁺ which crosses the BBB and dissolves in the CSF.

2. Kidneys: control HCO₃^- which is important for long-term control & compensation of acid-base disturbances.

3. Blood: through buffering by plasma proteins & haemoglobin.

4. Bone: H⁺ may exchange with cations in bone. Bone possesses carbonate which could be used to support plasma HCO₃^- levels.

5. Liver: generation of HCO₃^- and NH₄⁺ (ammonia) through glutamine metabolism. Excretion of ammonia by renal tubules generates more bicarbonate.

Reference(s)

Barrett, K.E., Barman, S.M., Brooks, H.L., X, J. and Ganong, W.F. (2019). Ganong’s review of medical physiology. 26th ed. New York: Mcgraw-Hill Education