Analysis by Computer Simulation of Factors Affecting the Extracellular Slow Wave Features of the Human Colon

Abstract: The study reported in this paper analyses, by computer simulation, factors affecting the features (amplitude, frequency and phase lag) of the slow waves of the extracellular myoelectrical activity of the human ascending colon. It takes into account both the anatomic and functional aspects of the colon haustra, the myoelectrical dynamics of the cells and the geometric modification of haustra ’ configuration. The variable sacculated geometry of the colon wall, segmented into typical haustra, has been represented by a sequence of truncated round ellipsoids. According to the propagation of the front of depolarization-repolarization of the cells, slow waves are simulated by the cyclic movement of an annular band polarized by electrical dipoles oriented perpendicularly with respect to the surface of the ellipsoids and activated by a pacemaker. The simulation highlighted that the amplitude of the slow waves physiologically depends on the dipole moment of cells, and the frequency depends on the velocity of the polarized annular band. In addition, the amplitude, the frequency and the phase lag also depend on the dynamic modification of the geometrical factors (colon length and haustrum radius). Furthermore, the simulation results showed that the shape of the slow wave and the amplitude of its peaks depend on the inter-electrode distance and on th