Dynamic Modelling Of The Human Respiratory System

PhD thesisThe human respiratory system is simulated on a digital computer by two dynamic models. In the first model only the arterial chemoreceptors are included in the controller while in the second one, the central medullary sensors are also present and brain and cerebrospinal fluid compartments are separated from the rest of the body tissues. In contrast to the previous models presented by other workers, the controller in these models modifies and regulates the neural drive signal discretely for every breath while the plant functions continuously. The Hering-Breuer reflexes are represented and the optimum values of the rate and depth of breathing are found at the end of every breath to minimize the respiratory work considering the effects of lungs elastance and airway resistance and turbulence. Lungs are regarded as an elastic bag with time variant volume and a varying dead space is included. Two different ventilation equations have been investigated and the models have been tested for a variety of respiratory stimuli. The simulation results were always stable and close to the experimental values. The structure of the models is described in detail and some of the simulation results are presented