iConcept Press Logo
Email Password Remember me
iConcept Journal of Computational and Mathematical Biology
iConcept Journal of Computational and Mathematical Biology
Maurice Ling
iConcept Press

iConcept Journal of Computational and Mathematical Biology

Modeling the Delay of Mucous Flow at Carinal Ridges of the Human Tracheobronchial Tree

by Robert Sturm

Volume: 3 (2014); Issue: 6


Numerous experimental studies have underlined that tracheobronchial clearance in human lungs includes a fast mucociliary phase and a slow bronchial clearance phase, whose mechanisms are not completely understood at the moment. In the present contribution, another phenomenon responsible for retention times > 24 h is introduced: the delay and temporary accumulation of mucus (particles) at the carinal ridges of single airway bifurcations. For an appropriate modeling of this specific mechanism, 4 mathematical approaches with different complexity have been developed and applied to available experimental data. While approaches I and II simply describe the randomly selected delay (time interval [tmin, tmax]) of either the whole mucus layer or a part of the mucus, approaches III and IV calculate single particle trajectories and also include several physiological considerations (e.g. loss of cilia on the carinal ridge due to an increased interception of inhaled particles). Preliminary modeling results show that carinal delay times are of main importance in the proximal bronchial airway generations (1 – 6), but play only a minor role in the distal airway generations. Depending on the used delay model, retained mass at a given time can be subject to an increase of 20 % with respect to the original ‘non-delay’ model. Comparison between results derived from aerosol bolus experiments and predicted data confirm that bronchial clearance in the upper airways can be explained sufficiently by a) the mucociliary escalator and b) a carinal clearance phase with significantly reduced transport times.

Author Details

Robert Sturm
Department of Physics and Biophysics, Faculty of Natural Sciences, University of Salzburg, Austria

Download Full Paper