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., Boitano, S., Brooks, H.L., Weitz, M., Brian Patrick Kearns, Ganong, W.F. and Mcgraw-Hill Education (Firm (2016). Ganong’s review of medical physiology. 25th ed. New York: Mcgraw Hill Education.
Hall, J.E. and Hall, M.E. (2020). Guyton And Hall Textbook Of Medical Physiology. 14th ed. S.L.: Elsevier - Health Science.
West, J.B. and Luks, A.M. (2021). West’s Pulmonary Pathophysiology. Lippincott Williams & Wilkins.