Mechanics of a rigid resistive bronchiole with compliant alveolar sac. The driving pressure is at entrance to the bronchiole; the reference extrathoracic pressure is constant at zero.
Description
This model represents a rigid bronchiole with a compliant alveolar sac. The resistance offered by bronchial wall to the flow of air is represented by the resistor in the model. The alveolar sac compliance is repsented by a capcitor. This model lacks the pleural pressure because of which a pressure pulse is used to drive the model.The pressure pulse represents the pressure difference in the alveolar space and the pleural sac. The alveolar sac changes its volume as a function of inlet flow or pressure. For a step function in the pressure the volume of the alveolar sac increases as an exponential function.
Figure Legend:
Finlet: Inlet Flow, P: Pressure, R: Resistance, F: Flow, Com: Compliance, V: Volume.
Equations
Pinlet - P2 = Finlet * R1 P2 - P3 = Finlet * R2 P3 - P4 = (V1 - V1_0)/Com1 d(V1)/dt = Finlet Where: P is pressure, F is flow, R is resistance, Com is capacitance, and V is the volume.
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K. R. Lutchen and G. M. Saidel, "Estimation of mechanical parameters in multicompartment models applied to normal and obstructed lungs during tidal breathing," IEEE Trans. Biomed. Eng., vol. BME-33, no. 9, pp. 878-887, Sept. 1986. Levitzky MG. "Mechanics of Breathing", Pulmonary Physiology. 7th Edition, New York: McGraw-Hill, 2007, p. 11?53
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The National Simulation Resource, Director J. B. Bassingthwaighte, Department of Bioengineering, University of Washington, Seattle WA 98195-5061.
Model development and archiving support at https://www.imagwiki.nibib.nih.gov/physiome provided by the following grants: NIH U01HL122199 Analyzing the Cardiac Power Grid, 09/15/2015 - 05/31/2020, NIH/NIBIB BE08407 Software Integration, JSim and SBW 6/1/09-5/31/13; NIH/NHLBI T15 HL88516-01 Modeling for Heart, Lung and Blood: From Cell to Organ, 4/1/07-3/31/11; NSF BES-0506477 Adaptive Multi-Scale Model Simulation, 8/15/05-7/31/08; NIH/NHLBI R01 HL073598 Core 3: 3D Imaging and Computer Modeling of the Respiratory Tract, 9/1/04-8/31/09; as well as prior support from NIH/NCRR P41 RR01243 Simulation Resource in Circulatory Mass Transport and Exchange, 12/1/1980-11/30/01 and NIH/NIBIB R01 EB001973 JSim: A Simulation Analysis Platform, 3/1/02-2/28/07.