Jejunum Health Dictionary

All the alimentary canal beyond below the stomach. In it, most DIGESTION is carried on, and through its walls all the food material is absorbed into the blood and lymph streams. The length of the intestine in humans is about 8·5–9 metres (28–30 feet), and it takes the form of one continuous tube suspended in loops in the abdominal cavity.

Divisions The intestine is divided into small intestine and large intestine. The former extends from the stomach onwards for 6·5 metres (22 feet) or thereabouts. The large intestine is the second part of the tube, and though shorter (about 1·8 metres [6 feet] long) is much wider than the small intestine. The latter is divided rather arbitrarily into three parts: the duodenum, consisting of the ?rst 25–30 cm (10–12 inches), into which the ducts of the liver and pancreas open; the jejunum, comprising the next 2·4–2·7 metres (8–9 feet); and ?nally the ileum, which at its lower end opens into the large intestine.

The large intestine begins in the lower part of the abdomen on the right side. The ?rst part is known as the caecum, and into this opens the appendix vermiformis. The appendix is a small tube, closed at one end and about the thickness of a pencil, anything from 2 to 20 cm (average 9 cm) in length, which has much the same structure as the rest of the intestine. (See APPENDICITIS.) The caecum continues into the colon. This is subdivided into: the ascending colon which ascends through the right ?ank to beneath the liver; the transverse colon which crosses the upper part of the abdomen to the left side; and the descending colon which bends downwards through the left ?ank into the pelvis where it becomes the sigmoid colon. The last part of the large intestine is known as the rectum, which passes straight down through the back part of the pelvis, to open to the exterior through the anus.

Structure The intestine, both small and large, consists of four coats, which vary slightly in structure and arrangement at di?erent points but are broadly the same throughout the entire length of the bowel. On the inner surface there is a mucous membrane; outside this is a loose submucous coat, in which blood vessels run; next comes a muscular coat in two layers; and ?nally a tough, thin peritoneal membrane. MUCOUS COAT The interior of the bowel is completely lined by a single layer of pillar-like cells placed side by side. The surface is increased by countless ridges with deep furrows thickly studded with short hair-like processes called villi. As blood and lymph vessels run up to the end of these villi, the digested food passing slowly down the intestine is brought into close relation with the blood circulation. Between the bases of the villi are little openings, each of which leads into a simple, tubular gland which produces a digestive ?uid. In the small and large intestines, many cells are devoted to the production of mucus for lubricating the passage of the food. A large number of minute masses, called lymph follicles, similar in structure to the tonsils are scattered over the inner surface of the intestine. The large intestine is bare both of ridges and of villi. SUBMUCOUS COAT Loose connective tissue which allows the mucous membrane to play freely over the muscular coat. The blood vessels and lymphatic vessels which absorb the food in the villi pour their contents into a network of large vessels lying in this coat. MUSCULAR COAT The muscle in the small intestine is arranged in two layers, in the outer of which all the ?bres run lengthwise with the bowel, whilst in the inner they pass circularly round it. PERITONEAL COAT This forms the outer covering for almost the whole intestine except parts of the duodenum and of the large intestine. It is a tough, ?brous membrane, covered upon its outer surface with a smooth layer of cells.... intestine

Uptake by the body tissues of ?uids or other substances. For example, food is absorbed from the digestive tract into the blood and lymph systems. Food is absorbed mainly in the small INTESTINE (jejunum and ileum), which is lined by multiple villi that increase its surface area. (See also DIGESTION; ASSIMILATION.)... absorption

Around one in 100 people suffers from coeliac disease, a condition in which the small INTESTINE fails to digest and absorb food, but many have no or few symptoms and remain undiagnosed. The intestinal lining is permanently sensitive to the protein gliadin (an insoluble and potentially toxic PEPTIDE protein) which is contained in GLUTEN, a constituent of the germ of wheat, barley and rye. As bread or other grain-based foods are a regular part of most people’s diet, the constant presence of gluten in the intestine of sufferers of coeliac disease causes atrophy of the digestive and absorptive cells of the intestine. Children are usually diagnosed when they develop symptoms such as vomiting, diarrhoea, lethargy, ANAEMIA, swollen abdomen and pale, frothy, foul-smelling faeces with failure to thrive. The diagnosis is usually made by a positive blood antibody test such as antiendomysial antibodies. However, because there may be an occasional false positive result, the ‘gold standard’ is to obtain a biopsy of the JEJUNUM through a tiny metal capsule that can be swallowed, a specimen taken, and the capsule retrieved. Though coeliac disease was long thought to occur in childhood, a second peak of the disorder has recently been identi?ed among people in their 50s.

Not all sufferers from coeliac disease present with gastrointestinal symptoms: doctors, using screening techniques, have increasingly identi?ed large numbers of such people. This is important because researchers have recently discovered that untreated overt and silent coeliac disease increases the risk of sufferers developing osteoporosis (brittle bone disease – see BONE, DISORDERS OF) and cancer. The osteoporosis develops because the bowel fails to absorb the CALCIUM essential for normal bone growth. Because those with coeliac disease lack the enzyme LACTASE, which is essential for digesting milk, they avoid milk – a rich source of calcium.

The key treatment is a strict, lifelong diet free of gluten. As well as returning the bowel lining to normal, this diet results in a return to normal bone density. People with coeliac disease, or parents or guardians of affected children, can obtain help and guidance from the Coeliac Society of the United Kingdom. (See also MALABSORPTION SYNDROME; SPRUE.)... coeliac disease

The first part of the small intestine extending from the pylorus (the muscular valve at the lower end of the stomach) to the ligament of Treitz, which marks the boundary between the duodenum and the jejunum (the second part of the small intestine). It is about 25 cm long and shaped like a C; it forms a loop around the head of the pancreas. Ducts from the pancreas, liver, and gallbladder feed into the duodenum through a small opening. Digestive enzymes in the pancreatic secretions and chemicals in the bile are released into the duodenum through this opening.... duodenum

A diagnostic test in which a small piece of tissue is removed from the lining of the jejunum for microscopic examination.

It is especially useful in the diagnosis of Crohn’s disease, coeliac disease, lymphoma, and other causes of malabsorption.

The biopsy is taken using an endoscope passed down the throat into the small intestine, via the stomach.... jejunal biopsy

The final, longest, and narrowest section of the small intestine. It is joined at its upper end to the jejunum and at its lower end to the large intestine (comprising the caecum, colon, and rectum). The function of the ileum is to absorb nutrients from food that has been digested in the stomach and the first 2 sections of the small intestine (the duodenum and the jejunum).

Occasionally the ileum becomes obstructed, for example by pushing through a weakness in the abdominal wall (see hernia) or by becoming caught up with scar tissue following abdominal surgery

(see adhesion). Other disorders of the ileum include Meckel’s diverticulum and diseases in which absorption of nutrients is impaired, such as Crohn’s disease, coeliac disease, tropical sprue, and lymphoma.... ileum

A parasitic infection caused by the nematodes Ancylostoma duodenale and Necator americanus, resulting in hookworm disease. These infections are exceedingly common in tropical and developing countries, millions of people being affected. Classically, A. duodenale occurred in the Far East, Mediterranean littoral, and Middle East, and N. americanus in tropical Africa, Central and South America, and the Far East; however, in recent years, geographical separation of the two human species is less distinct. In areas where standards of hygiene and sanitation are unsatisfactory, larvae (embryos) enter via intact skin, usually the feet. ‘Ground itch’ occasionally occurs as larvae enter the body. They then undergo a complex life-cycle, migrating through the lungs, trachea, and pharynx. Adult worms are 5–13 (mean 12) mm in length; their normal habitat is the small INTESTINE – especially the jejunum – where they adhere to the mucosa by hooks, thus causing seepage of blood into the lumen. A worm-pair produces large numbers of eggs, which are excreted in faeces; when deposited on moist soil they remain viable for many weeks or months. Clinical manifestations include microcytic hypochromic ANAEMIA, hypoalbuminaemia (low serum protein) and, in a severe case, OEDEMA. A chronic infection in childhood can give rise to physical, mental and sexual retardation. Treatment is with one of the benzimidazole compounds, usually mebendazole or albendazole; however, in developing countries, cheaper preparations are used, including tetrachloroethylene, bephenium hydroxynaphthoate, and pyrantel embonate. Anaemia usually responds to iron supplements; blood transfusion is rarely indicated.

Ancylostoma braziliensis A nematode infection of dogs, which in humans causes local disease (larva migrans) only, generally on the soles of the feet. It is usually acquired by walking on beaches contaminated with dog faeces in places such as the Caribbean.... ancylostomiasis

The ENZYME secreted in the DUODENUM and jejunum (see INTESTINE) which converts the enzyme, trypsinogen, secreted by the PANCREAS, into TRYPSIN. (See also DIGESTION.)... enterokinase

Motilin is a hormone (see HORMONES) formed in the DUODENUM and the JEJUNUM which plays a part in controlling the movements of the stomach and the gut.... motilin

Surgery to create a connection between the stomach and the jejunum, sometimes combined with partial gastrectomy.

The operation was formerly performed to treat duodenal ulcer (see peptic ulcer) but is now rare.... gastroenterostomy

A rare condition characterized by severe and recurrent peptic ulcers in the stomach, duodenum, and jejunum (the 2nd part of the small intestine). Zollinger–Ellison syndrome is caused by 1 or more tumours in the pancreas that secrete the hormone gastrin. Gastrin stimulates production of large quantities of acid by the stomach, which leads to ulceration. The high levels of acid in the digestive tract often also cause diarrhoea.

The tumours are cancerous, but of a slow-growing type.

If possible, they are removed surgically.

Proton pump inhibitor drugs are given to treat the ulcers.... zollinger–ellison syndrome

A chronic in?ammatory bowel disease which has a protracted, relapsing and remitting course. An autoimmune condition, it may last for several years. There are many similarities with ULCERATIVE COLITIS; sometimes it can be hard to di?erentiate between the two conditions. A crucial di?erence is that ulcerative colitis is con?ned to the colon (see INTESTINE), whereas Crohn’s disease can affect any part of the gastrointestinal tract, including the mouth and anus. The sites most commonly affected in Crohn’s disease (in order of frequency) are terminal ILEUM and right side of colon, just the colon, just the ileum and ?nally the ileum and JEJUNUM. The whole wall of the affected bowel is oedamatous (see OEDEMA) and thickened, with deep ulcers a characteristic feature. Ulcers may even penetrate the bowel wall, with abscesses and ?stulas developing. Another unusual feature is the presence in the affected bowel lining of islands of normal tissue.

Crohn’s disease is rare in the developing world, but in the western world the incidence is increasing and is now 6–7 per 100,000 population. Around 80,000 people in the UK have the disorder with more than 4,000 new cases occurring annually. Commonly Crohn’s disease starts in young adults, but a second incidence surge occurs in people over 70 years of age. Both genetic and environmental factors are implicated in the disease – for example, if one identical twin develops the disease, the second twin stands a high chance of being affected; and 10 per cent of sufferers have a close relative with in?ammatory bowel disease. Among environmental factors are low-residue, high-re?ned-sugar diets, and smoking.

Symptoms and signs of Crohn’s disease depend on the site affected but include abdominal pain, diarrhoea (sometimes bloody), ANOREXIA, weight loss, lethargy, malaise, ANAEMIA, and sore tongue and lips. An abdominal mass may be present. Complications can be severe, including life-threatening in?ammation of the colon (which may cause TOXAEMIA), perforation of the colon and the development of ?stulae between the bowel and other organs in the abdomen or pelvis. If Crohn’s disease persists for a decade or more there is an increased risk of the victim developing colon cancer. Extensive investigations are usually necessary to diagnose the disease; these include blood tests, bacteriological studies, ENDOSCOPY and biopsy, and barium X-ray examinations.

Treatment As with ulcerative colitis, treatment is aimed primarily at controlling symptoms. Physicians, surgeons, radiologists and dietitians usually adopt a team approach, while counsellors and patient support groups are valuable adjuncts in a disease that is typically lifelong. Drug treatment is aimed at settling the acute phase and preventing relapses. CORTICOSTEROIDS, given locally to the affected gut or orally, are used initially and the effects must be carefully monitored. If steroids do not work, the immunosuppressant agent AZATHIOPRINE should be considered. Antidiarrhoeal drugs may occasionally be helpful but should not be taken during an acute phase. The anti-in?ammatory drug SULFASALAZINE can be bene?cial in mild colitis. A new generation of genetically engineered anti-in?ammatory drugs is now available, and these selective immunosuppressants may prove of value in the treatment of Crohn’s disease.

Diet is important and professional guidance is advisable. Some patients respond to milk- or wheat-free diets, but the best course for most patients is to eat a well-balanced diet, avoiding items that the sufferer knows from experience are poorly tolerated. Of those patients with extensive disease, as many as 80 per cent may require surgery to alleviate symptoms: a section of affected gut may be removed or, as a lifesaving measure, a bowel perforation dealt with.

(See APPENDIX 2: ADDRESSES: SOURCES OF INFORMATION, ADVICE, SUPPORT AND SELFHELP – Colitis; Crohn’s disease.)... crohn’s disease

Linn. emend. Huds.

Family: Labiatae; Lamiaceae.

Habitat: Native to Europe; cultivated in Maharashtra, Kashmir and Punjab.

English: Peppermint, Brandy Mint.

Ayurvedic: Vilaayati Pudinaa.

Action: Oil—digestive, carminative, chloretic, antispasmodic, diuretic, antiemetic, mild sedative, diaphoretic, antiseptic, antiviral, used in many mixtures of indigestion and colic and cough and cold remedies.

Key application: Leaf—internally for spastic complaints of the gastrointestinal tract, gallbladder and bile ducts. (German Commission E, ESCOP.) The British Herbal Compendium indicates peppermint leaf for dyspepsia, flatulence, intestinal colic, and biliary disorders.

Key application: Oil—as a carminative. (The British Herbal Pharmacopoeia.) In spastic discomfort fo the upper gastrointestinal tract and bile ducts, irritable colon, the respiratory tract and inflammation of the oral mucosa. Externally, for myalgia and neuralgia. (German Commission E.) ESCOP indicates its use for irritable bowel syndrome, coughs and colds. Externally, for coughs and colds, rheumatic complaints, pruritus, urticaria, and pain in irritable skin conditions. (ESCOP.)

The essential oil has both antibacterial and antifungal properties.

The major constituents of the essential oil are: menthol, menthone, pulegone, menthofuran, 1,8-cineole, men- thyl acetate, isomenthone. The leaves contain flavonoid glycosides, erioc- itrin, luteolin 7-O-rutinoside, hesperi- din, isorhoifolin, diosmin, eriodictyol 7-O-glucoside and narirutin, besides rosmarinic acid, azulenes, cholene, carotenes.

Peppermint oil relaxed carvachol- contracted guinea-pig tenia coli, and inhibited spontaneous activity in guinea-pig colon and rabbit jejunum. It relaxes gastrointestinal smooth muscle by reducing calcium influx. Peppermint oil reduced gastric emptying time in dyspeptics.

The aqueous and ethanolic extracts exhibited antiviral activity against RPV (rinder pest virus), a highly contagious viral disease of cattle.... mentha piperata

compound glands of the small intestine, found in the *duodenum and the upper part of the jejunum. They are embedded in the submucosa and secrete mucus. [J. C. Brunner (1856–1927), Swiss anatomist]... brunner’s glands

an abnormality of small blood vessels (microscopically, an arteriovenous malformation), identified predominantly in the mucosal lining of the upper stomach, that may cause severe spontaneous haemorrhage. It can rarely be found in the duodenum, colon, jejunum, or oesophagus. If detected endoscopically, curative therapy is often possible, although the abnormality is often difficult to see at gastroscopy. Surgical exploration may be required if the bleeding is unresponsive to endoscopic treatment. [G. Dieulafoy (1839–1911), French physician]... dieulafoy’s lesion

Stapf.

Family: Rutaceae.

Habitat: Native to tropical America; cultivated in Indian gardens.

Family: Umbelliferae; Apiaceae.

Habitat: Native to the Mediterranean region; cultivated in Uttar Pradesh., Punjab, Assam and Orissa.

English: Anise, Aniseed.

Unani: Anisoon, Baadiyaan-roomi.

Action: Carminative, diuretic, anticholerin, antispasmodic, expectorant. Used for flatulence, dry coughs, whooping cough, bronchitis.

Key application: Internally in dyspeptic complaints; internally and externally in catarrhs of the respiratory tract. (German Commission E, ESCOP, WHO, The British Herbal Pharmacopoeia.)

The fruit gave volatile oil consisting mainly of trans-anethole (70-90%), with estragole, anise ketone, anisic acid, beta-caryophyllene, anisaldehyde, linalool. The fruit contained traces of furocoumarins; seeds gave benzoic acid, caffeic acid, containing protein and myristicin. Roots afforded sterols, coumarins and flavone glyco- sides. Aniseed has been demonstrated to increase the mucociliary transport in vitro and to significantly increase liver-regeneration in rats.

Aniseed is also used as a galacta- gogue. This property is thought due to the presence of polymers of anethole, dianethole and photoanethole.

Aqueous extract of roasted aniseed is reported to show cholinomimetic effect on rat blood pressure, rat jejunum and frog rectus abdominis preparations.

Alcoholic extract of aniseeds possesses antimicrobial and fungicidal activity.

Anethole has a structure similar to catecholamines including adrenaline, noradrenaline and dopamine and to the hallucinogenic compound myris- ticin as well. (Natural Medicines Comprehensive Database, 2007.)... pilocarpus microphyllus

n. a surgical operation in which the *jejunum is joined to an opening made in the stomach. This is usually done in preference to *gastroduodenostomy. See also jejunostomy.... gastrojejunostomy

(jejuno-) combining form denoting the jejunum.... jejun

n. surgical removal of part or the entirety of the jejunum.... jejunectomy

n. an operation in which part of the jejunum is joined to the distal ileum following the removal or bypass of diseased segments of small bowel. It was formerly used for the treatment of obesity but has been abandoned because of deleterious side-effects.... jejunoileostomy

The group of organs responsible for digestion. It consists of the digestive tract (also known as the alimentary tract or canal) and various associated organs. The digestive tract consists of the mouth, pharynx, oesophagus, stomach, intestines, and the anus. The intestines are the small intestine (comprising the duodenum, jejunum, and ileum) and the large intestine (comprising the caecum, colon, and rectum). The associated organs, such as the salivary glands, liver, and pancreas, secrete digestive juices that break down food as it goes through the tract.

Food and the products of digestion are moved from the throat to the rectum by peristalsis (waves of muscular contractions of the intestinal wall).

Food is broken down into simpler substances before being absorbed into the bloodstream.Physical breakdown is performed by the teeth, which cut and chew, and the stomach, which churns the food. The chemical breakdown of food is performed by the action of enzymes, acids, and salts.

Carbohydrates are broken down into simple sugars. Proteins are broken down into polypeptides, peptides, and amino acids. Fats are broken down into glycerol, glycerides, and fatty acids.

In the mouth, saliva lubricates food and contains enzymes that begin to break down carbohydrates. The tongue moulds food into balls (called boli) for easy swallowing. The food then passes into the pharynx. From here, it is pushed into the oesophagus and squeezed down into the stomach, where it is mixed with hydrochloric acid and pepsin. Produced by the stomach lining, these substances help break down proteins. When the food has been converted to a semi-liquid consistency, it passes into the duodenum where bile salts and acids (produced by the liver) help to break down fats. Digestive juices released by the pancreas into the duodenum contain enzymes that further break down food. Breakdown ends in the small intestine, carried out by enzymes produced by glands in the intestinal lining. Nutrients are absorbed in the small intestine. The residue enters the large intestine, where water is absorbed. Undigested matter is expelled via the rectum and anus as faeces.... digestive system

n. an operation to enlarge the capacity of and to decrease the pressure within the bladder by incorporating a segment of bowel. In a clam cystoplasty, the bladder is cut across transversely from one side of the neck to the other side through the dome (fundus) of the bladder and a length of the ileum, jejunum, or colon is inserted as a patch. In the operation of ileocaecocystoplasty, the dome is removed by cutting across the bladder transversely or sagittally above the openings of the ureters; it is replaced by an isolated segment of caecum and terminal ileum. In ileocystoplasty the bladder is enlarged by an opened-out portion of small intestine. The bladder may be totally replaced by a reservoir constructed from either small or large intestine (see cystectomy).... cystoplasty

n. a surgical operation in which the whole or a part of the stomach is removed. Total gastrectomy, in which the oesophagus is joined to the jejunum, is usually performed for stomach cancer but occasionally for the *Zollinger-Ellison syndrome. In partial (or subtotal) gastrectomy the upper part of the stomach is joined to the duodenum or small intestine (gastroenterostomy); this operation (with vagotomy) was the definitive treatment for refractory peptic ulcer before the advent of *antisecretory drugs. It is still performed in the treatment of gastric antral disease. After gastrectomy capacity for food is reduced, sometimes leading to weight loss. Other complications of gastrectomy include *dumping syndrome, ulceration at the anastomosis, anaemia, and *malabsorption.... gastrectomy

n. a surgical operation in which the jejunum is brought through the abdominal wall as a *stoma. It may enable the insertion of a jejunal catheter for short-term infusion of nutrients or other substances. A feeding jejunostomy is a tube inserted into the jejunum using endoscopic or surgical techniques to allow the introduction of nutrients. This may be required when disease, previous surgery, or refractory vomiting prevents the placement of a *gastrostomy (PEG) tube. A percutaneous endoscopic gastrojejunostomy (PEG-J) is a jejunal extension that is applied to an existing PEG tube.... jejunostomy

n. surgical incision of the jejunum.... jejunotomy

a technique using an end-to-side anastomosis between a defunctioned section of jejunum and another upper abdominal organ (e.g. stomach, duodenum, common bile duct) in order to bypass an obstruction.... roux-en-y

(enteroclysis) a radiological technique for examining the jejunum and ileum by passing a tube through the nose, oesophagus, and stomach into the small bowel and directly injecting *barium sulphate. Images are captured in real time as the contrast moves through the small bowel. It produces highly detailed images of the small bowel, making it particularly useful for investigating coeliac disease and Crohn’s disease, as well as strictures, tumours, and obstructions. It can be combined with X-ray imaging, CT, or MRI.... small-bowel enema

a rare disorder in which there is excessive secretion of gastric juice due to high levels of circulating *gastrin, which is produced by a pancreatic tumour (see gastrinoma) or an enlarged pancreas. The high levels of stomach acid cause diarrhoea and peptic ulcers, which may be multiple, in unusual sites (e.g. jejunum), or which may quickly recur after *vagotomy or partial *gastrectomy. Treatment with proton-pump inhibitors, by removal of the tumour (if benign), or by total gastrectomy is usually effective. [R. M. Zollinger (1903–92) and E. H. Ellison (1918–70), US physicians]... zollinger–ellison syndrome

a breach in the lining (mucosa) of the digestive tract caused by the actions of gastric acid and pepsin. This may occur due to abnormally high levels of gastric acid or pepsin or when the mucosa has been damaged by chronic *Helicobacter pylori infection or by aspirin or NSAID use. A peptic ulcer may be found in the oesophagus (oesophageal ulcer, associated with reflux *oesophagitis); the stomach (see gastric ulcer); duodenum (see duodenal ulcer); jejunum (jejunal ulcer, usually in the *Zollinger-Ellison syndrome); in a Meckel’s *diverticulum; and close to a *gastroenterostomy (stomal ulcer, anastomotic ulcer, marginal ulcer).... peptic ulcer