Biomechanics of small bowel motility.

A biomechanical model and results of numerical simulation of the propagation of electromechanical waves of deformation along the small bowel are presented. The organ is modelled as a soft orthotropic cylindrical biological shell reinforced by orthogonally interwoven smooth muscle elements, embedded in a connective tissue network. The dynamic reaction starts as a response to the propagation of a depolarization wave along the smooth muscle layers. The muscle layers contract independently but in a coordinated way with the generation of active forces. The mechanical properties of the wall are assumed to be nonlinear. Deformations of the bioshell are finite. The governing system of equations is obtained and solved numerically. The finite-difference method of the second order accuracy over the time and space variables was used. The dynamics of strain distribution in the biological shell and shape changes are analysed.