A Fully Resolved Multiphysics Model of Gastric Peristalsis and Bolus Emptying in the Upper Gastrointestinal Tract

TL;DR

This paper introduces a comprehensive 3D multiphysics model of the upper gastrointestinal tract that simulates gastric peristalsis and bolus emptying, incorporating muscle fiber architecture and gravity effects to enhance understanding of digestive biomechanics.

Contribution

It extends previous esophageal models to simulate gastric peristalsis and bolus emptying, integrating fiber architecture and gravity-driven flow for the first time.

Findings

Successful simulation of gastric peristalsis

First-time modeling of gravity-driven bolus emptying

Provides a foundation for studying reflux and obesity treatments

Abstract

Over the past few decades, in silico modeling of organ systems has significantly furthered our understanding of their physiology and biomechanical function. In this work, we present a detailed numerical model of the upper gastrointestinal (GI) tract that not only accounts for the fiber architecture of the muscle walls, but also the multiphasic components they help transport during normal digestive function. Construction details for 3D models of representative stomach geometry are presented along with a simple strategy for assigning circular and longitudinal muscle fiber orientations for each layer. Based on our previous work that created a fully resolved model of esophageal peristalsis, we extend the same principles to simulate gastric peristalsis by systematically activating muscle fibers embedded in the stomach. Following this, for the first time, we simulate gravity driven bolus emptying into the stomach due to density differences between ingested contents and fluid contents of the stomach. This detailed computational model of the upper gastrointestinal tract provides a foundation on which future models can be based that seek to investigate the biomechanics of acid reflux and probe various strategies for gastric bypass surgeries to address the growing problem of adult obesity.