Alveolar ventilation equation

C indicates concentration. In the tissue compartment, the CO2 production rate from cellular metabolism, Vco, is balanc by net inflow versus outflow in the tissues i.e., Vco, = Q(f vco, co)-Noting that Ci co, 0 and combining the two equations, while converting concentrations to partial pressures, leads to the alveolar ventilation equation... 

The level of carbon dioxide is itself proportional to the amount of gas passing in and out of the alveoli (alveolar ventilation) according to the following equation ... 

Equation (3-13) shows that the equilibrium pH of the bicarbonate buffer system of plasma can be to some extent controlled by varying the partial pressure of carbon dioxide in the air to which the blood is exposed (i.e. in the lungs). Reduction in partial pressure results in carbon dioxide leaving the blood with a rise in the last term of Equation (3-13) provided that the bicarbonate concentration remains constant. The equilibrium pH of the buffer system and hence the pH of the blood consequently rise. Conversely an increase in partial pressure of carbon dioxide in the alveolar air will result in a fall in the pH of blood plasma. In practice the partial pressure of carbon dioxide in the alveolar air is controlled by the rate of pulmonary ventilation in relation to the rate of production of carbon dioxide by metabolic oxidation within the body. Increased ventilation (i.e. hyperventilation) will lower the partial pressure of carbon dioxide and raise the blood pH, while decreased ventilation raises the partial pressure, making the blood more acid (metabolic acidosis). Normally the respiratory centre controls the rate of ventilation to keep the partial pressure of carbon dioxide close to the normal value of 40 mmHg. 

The chemical plant is propelled by the ventilation of the lung, Ve which determines the alveolar PCO2 and PO2 according to the following mass-balance equations ... 

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