Mathematical analysis and digital simulation of the respiratory control system.

The report expresses the basic material balance relationships for the lung-blood-tissue gas transport and exchange system in a set of differential- difference equations containing a number of dependent time delays. Additional equations define the chemical details of transport and acid-base buffering, concentration equilibria, and blood flow behavior. Finally, a control function is included defining the dependence of ventilation upon CSF (H(+)), and arterial (H(+)) and PO2 at the carotid chemoceptors. A Fortran program was written for convenient digital simulation of the responses of the system to a wide variety of forcings, including CO2 inhalation, hypoxia at sea level, altitude hypoxia, and metabolic disturbances in acid-base balance. Both dynamic and steady-state behavior of the model were reasonably realistic.