Mechanical properties of the human gastrointestinal tract

The tensile properties of the human esophagus, stomach, small and large bowel were examined on an Instron 1221 tensiometer. The values of maximal stress and destructive strain were the following: for esophagus-1.2 MPa and 140%, respectively, for stomach axial specimens-0.7 MPa and 190%, for stomach transversal specimens-0.5 MPa and 190%, for small bowel transversal specimens-0.9 MPa and 140% and for large bowel transversal specimens-0.9 MPa and 180%. Tests conducted on small and large bowel axial specimens permitted examination of the intestinal wall as a multi-layered structure. The mechanical properties of tested bowels in axial and transversal directions were qualitatively different. The submucosa and muscular layers condition the mechanical strength of bowel wall, while the serosa and mucosa showed no significant strength. Reproducible results were generated for cadaveric and surgically removed stomach and small intestine, which showed their mechanical properties similar under certain storage conditions. The data received could be used for monitoring of the mechanical properties of bowel wall layers under different conditions and for checking of bowel distension sequences.