Many disorders of the gastrointestinal tract are caused by toxins (enterotoxins) in food or produced by infectious agents such as Enterobacter, Vibrio cholerae, enteroviruses (e.g. norovirus, Reoviridae) or parasites (e.g. Cryptosporidium, Hymenolepis, Toxocara, Trichuris spp.). More serious disorders may be due to defects in intestinal transport systems (acrodermatitis enteropathica, Hartnup's disease, sitosterolaemia) or hypersensitivity (coeliac disease) or may have an autoimmune aetiology (inflammatory bowel disease). The gut is protected by the gut-associated lymphoid tissue, intestinal L cells, and secreted IgA which can inhibit bacterial adhesion to the gut mucosa (see colonization factors). Other relevant entries are for cholera, colitis, dysentery, gastric cancer, guanylin, Helicobacter pylori, hereditary nonpolyposis colon cancer (see GTBP; Hirschsprung's disease; lactose; polyposis coli).
Subjects: Medicine and Health.