The comparison between experiment and control groups, showed significant difference in the thickness of muscle layer, showing the extent of 26.1 µm, 20.1 µm and 20.3 µm in the esophagus and stomach, small intestine and rectum, respectively, compared with the control group measures 54.9 µm, 37.9 µm and 47.4 µm in the esophagus and stomach, small intestine and rectum demonstrating that exposure to ETU induces abnormal development of the muscular layer of the digestive tract.