Gastrointestinal system

Abstract

The functions of the gastrointestinal (GI) tract include digestion, absorption, excretion, and protection. In this review, we focus on the electrical activity of the stomach and small intestine, which underlies the motility of these organs, and where the most detailed systems descriptions and computational models have been based to date. Much of this discussion is also applicable to the rest of the GI tract. This review covers four major spatial scales: cell, tissue, organ, and torso, and discusses the methods of investigation and the challenges associated with each. We begin by describing the origin of the electrical activity in the interstitial cells of Cajal, and its spread to smooth muscle cells. The spread of electrical activity through the stomach and small intestine is then described, followed by the resultant electrical and magnetic activity that may be recorded on the body surface. A number of common and highly symptomatic GI conditions involve abnormal electrical and/or motor activity, which are often termed functional disorders. In the last section of this review we address approaches being used to characterize and diagnose abnormalities in the electrical activity and how these might be applied in the clinical setting. The understanding of electrophysiology and motility of the GI system remains a challenging field, and the review discusses how biophysically based mathematical models can help to bridge gaps in our current knowledge, through integration of otherwise separate concepts.

Effects of electrical stimulation on isolated rodent gastric smooth muscle cells evaluated via a joint computational simulation and experimental approach

“…Computational simulations have previously been identified as a potential tool for increasing the efficiency of GES protocol research (9). This study proves this strategy is effective, by demonstrating that a large range of stimulation parameters may be evaluated in a combined simulation and experimental approach, without exhaustive experimental efforts.…”

“…It will also be necessary to determine how the identified GES protocols modulate the electrophysiological properties of SMCs across and between the gastric muscle layers and to determine the effects of the stimuli on ICC entrainment and ICC-SMC network functions. We anticipate that the role of multiscale gastric electrophysiology simulations will expand in this research field to support these complex experimental efforts (9). For example, a gastric tissue model has recently been developed and validated through high-resolution mapping, incorporating a continuum description of SMC tissue layers and an ICC entrainment algorithm (12).…”

“…Computational simulations have been proposed as a means to improve the efficiency of GES research, by employing advanced mathematical models that reduce the vast parameter combinations of all potential protocols to a much more refined pool of protocols (9,12). Previously, a limited number of gastrointestinal mathematical models have been used in pursuit of this purpose.…”

Experimental evidence and mathematical modeling of thermal effects on human colonic smooth muscle contractility

“…In summary, these findings may provide several different applications considering the complex electrical activity of the gastrointestinal system (16). First, the experimental setup used in this investigation can be adopted to study the pharmacological effects of single or multiple drugs at both experimental and modeling levels to identify possible therapeutic approaches for POI, in particular exploring the role of ICCs.…”

A physiome interoperability roadmap for personalized drug development

“…Models have also been developed for some functional aspects of parts of the digestive system including the oesophagus, stomach, duodenum and small intestines [50,51] but a vascular system model that ties all these together appears to rsfs.royalsocietypublishing.org Interface Focus 6: 20150094 be missing. Note that these models deal with wall motility and the enteric nervous system [52,53] and three-dimensional flow processes [54], but are not yet coupled to membrane transport (although this is under development).…”