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58-560: A bezoar ( / ˈ b i z ɔː r / BEE -zor ) is a mass often found trapped in the gastrointestinal system , though it can occur in other locations. A pseudobezoar is an indigestible object introduced intentionally into the digestive system. There are several varieties of bezoar, some of which have inorganic constituents and others organic . The term has both modern (medical, scientific) and traditional usage. Esophageal bezoars discovered in nasogastrically fed patients on mechanical ventilation and sedation are reported to be due to

116-408: A barium -labeled meal, breath hydrogen analysis, scintigraphic analysis following a radiolabeled meal, and simple ingestion and spotting of corn kernels . It takes 2.5 to 3 hours for 50% of the contents to leave the stomach. The rate of digestion is also dependent of the material being digested, as food composition from the same meal may leave the stomach at different rates. Total emptying of

174-415: A symbiotic relationship. These bacteria are responsible for gas production at host–pathogen interface , which is released as flatulence . Intestinal bacteria can also participate in biosynthesis reactions. For example, certain strains in the large intestine produce vitamin B 12 ; an essential compound in humans for things like DNA synthesis and red blood cell production. However, the primary function of

232-403: A "through-gut" or complete digestive tract. Exceptions are more primitive ones: sponges have small pores ( ostia ) throughout their body for digestion and a larger dorsal pore ( osculum ) for excretion, comb jellies have both a ventral mouth and dorsal anal pores, while cnidarians and acoels have a single pore for both digestion and excretion. The human gastrointestinal tract consists of

290-623: A halfway-tense state but can relax in spots to allow for local distention and peristalsis . The gastrointestinal tract contains the gut microbiota , with some 1,000 different strains of bacteria having diverse roles in the maintenance of immune health and metabolism , and many other microorganisms . Cells of the GI tract release hormones to help regulate the digestive process. These digestive hormones , including gastrin , secretin , cholecystokinin , and ghrelin , are mediated through either intracrine or autocrine mechanisms, indicating that

348-436: A period of time during the operation due to its high risk of shock and hyponatremia . Gastric lavage is used infrequently in modern poisoning treatment. Some authorities have actually suggested that it not be used routinely, if ever, in poisoning situations. Lavage should only be considered if the amount of poison ingested is potentially life-threatening and the procedure can be performed within 60 minutes of ingestion. Lavage

406-482: Is a clear boundary between the gut and the surrounding tissue. These parts of the tract have a mesentery . Retroperitoneal parts are covered with adventitia . They blend into the surrounding tissue and are fixed in position. For example, the retroperitoneal section of the duodenum usually passes through the transpyloric plane . These include the esophagus , pylorus of the stomach, distal duodenum , ascending colon , descending colon and anal canal . In addition,

464-411: Is a thin muscle which is derived from the embryonic mesoderm . The lower gastrointestinal tract includes most of the small intestine and all of the large intestine . In human anatomy , the intestine ( bowel or gut ; Greek: éntera ) is the segment of the gastrointestinal tract extending from the pyloric sphincter of the stomach to the anus and as in other mammals, consists of two segments:

522-479: Is about 30 m (320 sq ft). The combination of the circular folds , the villi, and the microvilli increases the absorptive area of the mucosa about 600-fold, making a total area of about 250 m (2,700 sq ft) for the entire small intestine. Its main function is to absorb the products of digestion (including carbohydrates, proteins, lipids, and vitamins) into the bloodstream. There are three major divisions: The large intestine , also called

580-532: Is also the initial treatment for duodenal atresia in newborns, a condition where the small intestine is closed distal to the stomach, causing food and fluid to accumulate in the stomach. When the body temperature rises above 40 °C , gastric lavage with iced saline also can be an aggressive cooling measure in a medical emergency . Lavage is contraindicated when patients have a compromised, unprotected airway and in patients at risk of gastrointestinal hemorrhage or perforation. Relative contraindications include when

638-408: Is bound to sulfur compounds in the protein of degraded hair, which is a key component in bezoars. A famous case in the common law of England ( Chandelor v Lopus , 79 Eng Rep. 3, Cro. Jac. 4, Eng. Ct. Exch. 1603) announced the rule of caveat emptor ("let the buyer beware") if the goods purchased are not in fact genuine and effective. The case concerned a purchaser who sued for the return of

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696-399: Is opened. Apart from toxicology, gastric lavage (or nasogastric lavage) is sometimes used to confirm levels of bleeding from the upper gastrointestinal tract. It may play a role in the evaluation of hematemesis . It can also be used as a cooling technique for hyperthermic patients. Gastric lavage involves the passage of a tube (such as an Ewald tube ) via the mouth or nose down into

754-408: Is referred to as faeces . The outermost layer of the gastrointestinal tract consists of several layers of connective tissue . Intraperitoneal parts of the GI tract are covered with serosa . These include most of the stomach , first part of the duodenum , all of the small intestine , caecum and appendix , transverse colon , sigmoid colon and rectum . In these sections of the gut, there

812-430: Is the process of cleaning out the contents of the stomach using a tube. Since its first recorded use in the early 19th century, it has become one of the most routine means of eliminating poisons from the stomach. Such devices are normally used on a person who has ingested a poison or overdosed on a drug such as ethanol . They may also be used before surgery , to clear the contents of the digestive tract before it

870-416: Is thought to have evolved within the nephrozoan clade of Bilateria , after their ancestral ventral orifice (single, as in cnidarians and acoels ; re-evolved in nephrozoans like flatworms ) stretched antero-posteriorly, before the middle part of the stretch would get narrower and closed fully, leaving an anterior orifice (mouth) and a posterior orifice (anus plus genital opening ). A stretched gut without

928-464: Is used, as children are more at risk of developing hyponatremia if lavaged with water. Because of the possibility of vomiting, a suction device is always on hand in case of pulmonary aspiration of stomach contents. Lavage is repeated until the returning fluid shows no further gastric contents. If the patient is unconscious or cannot protect their airway then the patient should be intubated before performing lavage. The person must be anaesthetised for

986-524: The antiporter activities, are also instrumental in the intestine's role of drug metabolism in the detoxification of antigens and xenobiotics . In most vertebrates , including amphibians , birds , reptiles , egg-laying mammals , and some fish , the gastrointestinal tract ends in a cloaca and not an anus . In the cloaca, the urinary system is fused with the genito-anal pore. Therians (all mammals that do not lay eggs, including humans) possess separate anal and uro-genital openings. The females of

1044-407: The esophagus , stomach, and intestines, and is divided into the upper and lower gastrointestinal tracts. The GI tract includes all structures between the mouth and the anus , forming a continuous passageway that includes the main organs of digestion, namely, the stomach , small intestine , and large intestine . The complete human digestive system is made up of the gastrointestinal tract plus

1102-534: The lipase LIPF , expressed in chief cells , and gastric ATPase ATP4A and gastric intrinsic factor GIF , expressed in parietal cells of the stomach mucosa. Specific proteins expressed in the stomach and duodenum involved in defence include mucin proteins, such as mucin 6 and intelectin-1 . The time taken for food to transit through the gastrointestinal tract varies on multiple factors, including age, ethnicity, and gender. Several techniques have been used to measure transit time, including radiography following

1160-483: The oral cavity has adventitia. Approximately 20,000 protein coding genes are expressed in human cells and 75% of these genes are expressed in at least one of the different parts of the digestive organ system. Over 600 of these genes are more specifically expressed in one or more parts of the GI tract and the corresponding proteins have functions related to digestion of food and uptake of nutrients. Examples of specific proteins with such functions are pepsinogen PGC and

1218-436: The small intestine and the large intestine . In humans, the small intestine is further subdivided into the duodenum , jejunum , and ileum while the large intestine is subdivided into the cecum , ascending, transverse, descending, and sigmoid colon , rectum , and anal canal . The small intestine begins at the duodenum and is a tubular structure, usually between 6 and 7 m long. Its mucosal area in an adult human

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1276-670: The Middle East in the 11th century and remained popular until it started to fall into disrepute by the 18th century. People believed that a bezoar had the power of a universal antidote and would work against any poison – a drinking glass that contained a bezoar could allegedly neutralize any poison poured into it. Ox bezoars ( niu-huang ( 牛黃 ) or calculi bovis ) are used in Chinese herbology to treat various diseases. They are gallstones or gallstone substitutes formed from ox or cattle bile . Some products allegedly remove toxins from

1334-457: The accessory organs of digestion (the tongue , salivary glands , pancreas , liver and gallbladder ). The tract may also be divided into foregut , midgut , and hindgut , reflecting the embryological origin of each segment. The whole human GI tract is about nine meters (30 feet) long at autopsy . It is considerably shorter in the living body because the intestines, which are tubes of smooth muscle tissue , maintain constant muscle tone in

1392-485: The blood and lymph circulatory systems. Fundamental components of this protection are provided by the intestinal mucosal barrier , which is composed of physical, biochemical, and immune elements elaborated by the intestinal mucosa. Microorganisms also are kept at bay by an extensive immune system comprising the gut-associated lymphoid tissue (GALT) There are additional factors contributing to protection from pathogen invasion. For example, low pH (ranging from 1 to 4) of

1450-507: The body. The Andalusian physician Ibn Zuhr ( d. 1161), known in the West as Avenzoar, is thought to have made the earliest description of bezoar stones as medicinal items. Extensive reference to bezoars also appears in the Picatrix . In 1567, French surgeon Ambroise Paré did not believe that it was possible for the bezoar to cure the effects of any poison and described an experiment to test

1508-465: The butyrate induces the differentiation of Treg cells by enhancing histone H3 acetylation in the promoter and conserved non-coding sequence regions of the FOXP3 locus, thus regulating the T cells , resulting in the reduction of the inflammatory response and allergies. The large intestine contains multiple types of bacteria that can break down molecules the human body cannot process alone, demonstrating

1566-445: The cells releasing these hormones are conserved structures throughout evolution . The structure and function can be described both as gross anatomy and as microscopic anatomy or histology . The tract itself is divided into upper and lower tracts, and the intestines small and large parts. The upper gastrointestinal tract consists of the mouth , pharynx , esophagus , stomach , and duodenum . The exact demarcation between

1624-496: The cola in doses of 500 ml (18 imp fl oz; 17 US fl oz) to up to 3,000 ml (110 imp fl oz; 100 US fl oz) over 24 hours, orally or by gastric lavage . A total of 91.3% of patients had complete resolution after treatment with Coca-Cola: 50% after a single treatment, with others requiring cola plus endoscopic removal. Doctors resorted to surgical removal in four cases. Gastrointestinal system Most animals have

1682-420: The colon, forms an arch starting at the cecum and ending at the rectum and anal canal . It also includes the appendix , which is attached to the cecum . Its length is about 1.5 m, and the area of the mucosa in an adult human is about 2 m (22 sq ft). Its main function is to absorb water and salts. The colon is further divided into: The gut is an endoderm -derived structure. At approximately

1740-422: The definitive gut as well. Each segment of the gut is further specified and gives rise to specific gut and gut-related structures in later development. Components derived from the gut proper, including the stomach and colon , develop as swellings or dilatations in the cells of the primitive gut. In contrast, gut-related derivatives — that is, those structures that derive from the primitive gut but are not part of

1798-483: The digestive tract called a gizzard used for grinding up food. Another feature found in a range of animals is the crop . In birds this is found as a pouch alongside the esophagus. In 2020, the oldest known fossil digestive tract, of an extinct wormlike organism in the Cloudinidae was discovered; it lived during the late Ediacaran period about 550 million years ago. A through-gut (one with both mouth and anus)

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1856-427: The duodenum are as follows (starting at the stomach, and moving toward the jejunum): bulb , descending, horizontal, and ascending. The suspensory muscle attaches the superior border of the ascending duodenum to the jejunum . The suspensory muscle is an important anatomical landmark that shows the formal division between the duodenum and the jejunum, the first and second parts of the small intestine, respectively. This

1914-625: The gastrointestinal tract include the upper and lower gastrointestinal series : Intestines from animals other than humans are used in a number of ways. From each species of livestock that is a source of milk , a corresponding rennet is obtained from the intestines of milk-fed calves . Pig and calf intestines are eaten, and pig intestines are used as sausage casings. Calf intestines supply calf-intestinal alkaline phosphatase (CIP), and are used to make goldbeater's skin . Other uses are: Gastric lavage Gastric lavage , also commonly called stomach pumping or gastric irrigation ,

1972-486: The gastrointestinal tract. The mucosa surrounds the lumen , or open space within the tube. This layer comes in direct contact with digested food ( chyme ). The mucosa is made up of: The mucosae are highly specialized in each organ of the gastrointestinal tract to deal with the different conditions. The most variation is seen in the epithelium. The submucosa consists of a dense irregular layer of connective tissue with large blood vessels, lymphatics, and nerves branching into

2030-418: The gut proper, in general, develop as out-pouchings of the primitive gut. The blood vessels supplying these structures remain constant throughout development. The gastrointestinal tract has a form of general histology with some differences that reflect the specialization in functional anatomy. The GI tract can be divided into four concentric layers in the following order: The mucosa is the innermost layer of

2088-574: The intestine that have physiological causes but do not have identifiable structural, chemical, or infectious pathologies. Several symptoms can indicate problems with the gastrointestinal tract, including: Gastrointestinal 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. Various methods of imaging

2146-490: The large intestine is water absorption from digested material (regulated by the hypothalamus ) and the reabsorption of sodium and nutrients. Beneficial intestinal bacteria compete with potentially harmful bacteria for space and "food", as the intestinal tract has limited resources. A ratio of 80–85% beneficial to 15–20% potentially harmful bacteria is proposed for maintaining homeostasis . An imbalanced ratio results in dysbiosis . Enzymes such as CYP3A4 , along with

2204-413: 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 gastrointestinal disorders the most common of which is irritable bowel syndrome . Functional constipation and chronic functional abdominal pain are other functional disorders of

2262-408: The layers of muscle are helical with different pitches. The inner circular is helical with a steep pitch and the outer longitudinal is helical with a much shallower pitch. Whilst the muscularis externa is similar throughout the entire gastrointestinal tract, an exception is the stomach which has an additional inner oblique muscular layer to aid with grinding and mixing of food. The muscularis externa of

2320-580: The middle part closed is present in another branch of bilaterians, the extinct proarticulates . This and the amphistomic development (when both mouth and anus develop from the gut stretch in the embryo) present in some nephrozoans (e.g. roundworms ) are considered to support this hypothesis. There are many diseases and conditions that can affect the gastrointestinal system, including infections , inflammation and cancer . Various pathogens , such as bacteria that cause foodborne illnesses , can induce gastroenteritis which results from inflammation of

2378-428: The most predominant bacterial groups in the GI tract, play an important role in influencing the dynamics of the gut's immune system. It has been demonstrated that the intake of a high fiber diet could be responsible for the induction of T-regulatory cells (Tregs). This is due to the production of short-chain fatty acids during the fermentation of plant-derived nutrients such as butyrate and propionate . Basically,

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2436-416: The mucosa and muscularis externa . It contains the submucosal plexus , an enteric nervous plexus , situated on the inner surface of the muscularis externa . The muscular layer consists of an inner circular layer and a longitudinal outer layer. The circular layer prevents food from traveling backward and the longitudinal layer shortens the tract. The layers are not truly longitudinal or circular, rather

2494-456: The poisoning is due to a corrosive substance (strong acids or strong bases) ( T54 ), hydrocarbons ( T53 ), or for poisons that have an effective antidote . It is also contraindicated in case of aluminum phosphide poisoning. Many complications have been reported, although it appears serious complications are uncommon. The most dangerous risk is aspiration pneumonia , which is more likely to occur if hydrocarbons are ingested in patients without

2552-464: The precipitation of certain food types rich in casein, which are precipitated with gastric acid reflux to form esophageal bezoars. Bezoars can also be caused by gastroparesis due to the slowing of gastric emptying, which allows food to form a bolus. The word bezoar is derived from the Persian pād-zahr ( پادزهر ), literally ' antidote ' . The myth of the bezoar as an antidote reached Europe from

2610-469: The primitive gut. The yolk sac remains connected to the gut tube via the vitelline duct . Usually, this structure regresses during development; in cases where it does not, it is known as Meckel's diverticulum . During fetal life, the primitive gut is gradually patterned into three segments: foregut , midgut , and hindgut . Although these terms are often used in reference to segments of the primitive gut, they are also used regularly to describe regions of

2668-478: The properties of bezoars by Gustaf Arrhenius and Andrew A. Benson of the Scripps Institution of Oceanography show that when bezoars are immersed in an arsenic-laced solution, they can remove the poison. The toxic compounds in arsenic are arsenate and arsenite ; each is acted upon differently by the bezoars: arsenate is removed by being exchanged for phosphate in brushite found in the stones, while arsenite

2726-482: The properties of the stone. A cook in the King's court was sentenced to death and chose to be poisoned rather than hanged, under the condition that he would be given a bezoar after the poison. Paré administered the bezoar stone to the cook, but it had no effect, and the cook died in agony seven hours after taking the poison, proving that – contrary to popular belief – the bezoar could not cure all poisons. Modern examinations of

2784-654: The purchase price of an allegedly fraudulent bezoar. Bezoars were important objects in cabinets of curiosity and in natural-history collections, mainly for their use in early-modern pharmacy and in the study of animal health. The Merck Manual of Diagnosis and Therapy notes that consumption of unripened persimmons has been identified as the main cause of epidemics of intestinal bezoars and that up to 90 percent of bezoars that occur from excessive consumption require surgery for removal. A 2013 review of three databases identified 24 publications presenting 46 patients treated with Coca-Cola for phytobezoars. Clinicians administered

2842-402: The rest of the autonomic nervous system . The coordinated contractions of these layers is called peristalsis and propels the food through the tract. Food in the GI tract is called a bolus (ball of food) from the mouth down to the stomach. After the stomach, the food is partially digested and semi-liquid, and is referred to as chyme . In the large intestine, the remaining semi-solid substance

2900-409: The sixteenth day of human development, the embryo begins to fold ventrally (with the embryo's ventral surface becoming concave ) in two directions: the sides of the embryo fold in on each other and the head and tail fold toward one another. The result is that a piece of the yolk sac , an endoderm -lined structure in contact with the ventral aspect of the embryo, begins to be pinched off to become

2958-412: 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 gastrointestinal tract, ulcerative colitis is limited to

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3016-430: The stomach and small intestine. Antibiotics to treat such bacterial infections can decrease the microbiome diversity of the gastrointestinal tract, and further enable inflammatory mediators. Gastroenteritis is the most common disease of the GI tract. 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

3074-406: The stomach followed by sequential administration and removal of small volumes of liquid. The placement of the tube in the stomach must be confirmed by pH testing a small amount of aspirated stomach contents, or x-ray. This is to ensure the tube is not in the lungs. In adults, small amounts of warm water or saline are administered and, via a siphoning action, removed again. In children, normal saline

3132-455: The stomach is composed of the inner oblique layer, middle circular layer, and the outer longitudinal layer. Between the circular and longitudinal muscle layers is the myenteric plexus . This controls peristalsis. Activity is initiated by the pacemaker cells, (myenteric interstitial cells of Cajal ). The gut has intrinsic peristaltic activity ( basal electrical rhythm ) due to its self-contained enteric nervous system. The rate can be modulated by

3190-409: The stomach is fatal for many microorganisms that enter it. Similarly, mucus (containing IgA antibodies ) neutralizes many pathogenic microorganisms. Other factors in the GI tract contribution to immune function include enzymes secreted in the saliva and bile . Beneficial bacteria also can contribute to the homeostasis of the gastrointestinal immune system. For example, Clostridia , one of

3248-453: The stomach takes around 4–5 hours, and transit through the colon takes 30 to 50 hours. The gastrointestinal tract forms an important part of the immune system . The surface area of the digestive tract is estimated to be about 32 square meters, or about half a badminton court. With such a large exposure (more than three times larger than the exposed surface of the skin ), these immune components function to prevent pathogens from entering

3306-409: The subgroup Placentalia have even separate urinary and genital openings. During early development , the asymmetric position of the bowels and inner organs is initiated (see also axial twist theory ). Ruminants show many specializations for digesting and fermenting tough plant material, consisting of additional stomach compartments . Many birds and other animals have a specialised stomach in

3364-458: The upper and lower tracts is the suspensory muscle of the duodenum . This differentiates the embryonic borders between the foregut and midgut, and is also the division commonly used by clinicians to describe gastrointestinal bleeding as being of either "upper" or "lower" origin. Upon dissection , the duodenum may appear to be a unified organ, but it is divided into four segments based on function, location, and internal anatomy. The four segments of

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