Diseases There are many diseases and conditions that can affect the<unk>  system, including infections, inflammation and cancer. Various pathogens, such as bacteria that cause foodborne illnesses, can induce gastroenteritis which results from inflammation of the stomach and small intestine. Antibiotics to treat such bacterial infections can decrease the microbiome diversity of the<unk> , and further enable inflammatory mediators. Gastroenteritis is the most common disease of the<unk> . *<unk>  cancer may occur at any point in the<unk> , and includes mouth cancer, tongue cancer, oesophageal cancer, stomach cancer, and colorectal cancer. * Inflammatory conditions. Ileitis is an inflammation of the ileum, colitis is an inflammation of the large intestine. * Appendicitis is inflammation of the appendix located at the caecum. This is a potentially fatal condition if left untreated; most cases of appendicitis require surgical intervention. Diverticular disease is a condition that is very common in older people in industrialized countries. It usually affects the large intestine but has been known to affect the small intestine as well. Diverticulosis occurs when pouches form on the intestinal wall. Once the pouches become inflamed it is known as diverticulitis. Inflammatory bowel disease is an inflammatory condition affecting the bowel walls, and includes the subtypes Crohn's disease and ulcerative colitis. While Crohn's can affect the entire<unk> , ulcerative colitis is limited to the large intestine. Crohn's disease is widely regarded as an autoimmune disease. Although ulcerative colitis is often treated as though it were an autoimmune disease, there is no consensus that it actually is such. Functional<unk>  disorders the most common of which is irritable bowel syndrome. Functional constipation and chronic functional abdominal pain are other functional disorders of the intestine that have physiological causes but do not have identifiable structural, chemical, or infectious pathologies. Symptoms Several symptoms are used to indicate problems with the<unk> : * Vomiting, which may include regurgitation of food or the vomiting of blood * Diarrhea, or the passage of liquid or more frequent stools * Constipation, which refers to the passage of fewer and hardened stools * Blood in stool, which includes fresh red blood, maroon-coloured blood, and tarry-coloured blood Treatment<unk>  surgery can often be performed in the outpatient setting. In the United States in 2012, operations on the digestive system accounted for 3 of the 25 most common ambulatory surgery procedures and constituted 9.1 percent of all outpatient ambulatory surgeries. Imaging Various methods of imaging the<unk>  include the upper and lower<unk>  series: * Radioopaque dyes may be swallowed to produce a barium swallow * Parts of the<unk>  may be visualised by camera. This is known as endoscopy if examining the upper<unk>  and colonoscopy or sigmoidoscopy if examining the lower<unk> . Capsule endoscopy is where a capsule containing a camera is swallowed in order to examine the<unk> . Biopsies may also be taken when examined. * An abdominal x-ray may be used to examine the lower<unk> . Other related diseases * Cholera * Enteric duplication cyst *<unk> ardiasis * Pancreatitis * Peptic ulcer disease * Yellow fever * Helicobacter pylori is a gram-negative spiral bacterium. Over half the world's population is infected with it, mainly during childhood; it is not certain how the disease is transmitted. It colonizes the<unk>  system, predominantly the stomach. The bacterium has specific survival conditions that our gastric microenvironment: it is both capnophilic and microaerophilic. Helicobacter also exhibits a tropism for gastric epithelial lining and the gastric mucosal layer about it. Gastric colonization of this bacterium triggers a robust immune response leading to moderate to severe inflammation, known as gastritis. Signs and symptoms of infection are gastritis, burning abdominal pain, weight loss, loss of appetite, bloating, burping, nausea, bloody vomit, and black tarry stools. Infection can be detected in a number of ways:<unk>  X-rays, endoscopy, blood tests for anti-Helicobacter antibodies, a stool test, and a urease breath test (which is a by-product of the bacteria). If caught soon enough, it can be treated with three doses of different proton pump inhibitors as well as two antibiotics, taking about a week to cure. If not caught soon enough, surgery may be required. * Intestinal pseudo-obstruction is a syndrome caused by a malformation of the digestive system, characterized by a severe impairment in the ability of the intestines to push and assimilate. Symptoms include daily abdominal and stomach pain, nausea, severe distension, vomiting, heartburn, dysphagia, diarrhea, constipation, dehydration and malnutrition. There is no cure for intestinal pseudo-obstruction. Different types of surgery and treatment managing life-threatening complications such as ileus and volvulus, intestinal stasis which lead to bacterial overgrowth, and resection of affected or dead parts of the gut may be needed. Many patients require parenteral nutrition. * Ileus is a blockage of the intestines. * Coeliac disease is a common form of malabsorption, affecting up to 1% of people of northern European descent. An autoimmune response is triggered in intestinal cells by digestion of gluten proteins. Ingestion of proteins found in wheat, barley and rye, causes villous atrophy in the small intestine. Lifelong dietary avoidance of these foodstuffs in a gluten-free diet is the only treatment. * Enteroviruses are named by their transmission-route through the intestine (enteric meaning intestinal), but their symptoms aren't mainly associated with the intestine. * Endometriosis can affect the intestines, with similar symptoms to IBS. * Bowel twist (or similarly, bowel strangulation) is a comparatively rare event (usually developing sometime after major bowel surgery). It is, however, hard to diagnose correctly, and if left uncorrected can lead to bowel infarction and death. (The singer Maurice<unk> bb is understood to have died from this.) * Angiodysplasia of the colon * Constipation * Diarrhea * Hirschsprung's disease (aganglionosis) * Intussusception * Polyp (medicine) (see also colorectal polyp) * Pseudomembranous colitis * Toxic megacolon usually a complication of ulcerative colitis
Gastrointestinal tract
Peripheral nervous system
Stomach
Central nervous system
Enteric nervous system
Reproductive system
Urinary system
Genitourinary system