GI tract

• 胃腸管、消化管

関

alimentary canal、alimentary tract、digestive tract、gastrointestinal、gastrointestinal tract、GI

WordNet

1. of or relating to the stomach and intestines; "a gastrointestinal disorder" (同)GI
2. a brief treatise on a subject of interest; published in the form of a booklet (同)pamphlet
3. an extended area of land (同)piece of land, piece of ground, parcel of land, parcel
4. a system of body parts that together serve some particular purpose
5. a drawing created by superimposing a semitransparent sheet of paper on the original image and copying on it the lines of the original image (同)trace
6. the act of drawing a plan or diagram or outline
7. the discovery and description of the course of development of something; "the tracing of genealogies"
8. the 7th letter of the Roman alphabet (同)g

PrepTutorEJDIC

1. 胃腸の,胃腸に影響する
2. 広大な土地(地域),(土地・海・空などの)広がり《+of+名》 / (器官の)管,(神経の)索
3. (おもに宗教・政治などの宣伝用の)小冊子,パンフレット
4. 跡を追うこと,追跡;透写,複写 / 〈C〉 / 透写(複写)によってできたもの(地図・図案など),透写図
5. アメリカ兵[Government Issue(政府支給)の略]・官給の,軍隊式の

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2014/02/13 13:23:10」(JST)

wiki en

[Wiki en表示]

"Alimentary canal" redirects here. For animal alimentary canal in general, see Gut (anatomy).

Human gastrointestinal tract (Digestive System)
Stomach colon rectum diagram
Latin	Tractus digestorius (mouth to anus), canalis alimentarius (esophagus to large Intestine), canalis gastrointestinales (stomach to large Intestine)
System	Digestive system

The human gastrointestinal tract (GI tract), refers to the stomach and intestine, and is divided into the upper and lower gastrointestinal tracts.It can also include all the structures from the mouth to the anus. (The digestive system is a broader term that includes other structures, including the digestive organs and their accessories).

The whole digestive tract is about nine metres long. The tract may also be divided into foregut, midgut, and hindgut, reflecting the embryological origin of each segment of the tract.

The GI tract constantly releases hormones to help regulate the digestive process. These hormones, including gastrin, secretin, cholecystokinin, and ghrelin, are mediated through either intracrine or autocrine mechanisms, indicating that the cells releasing these hormones are conserved structures throughout evolution.

Structure

Upper gastrointestinal tract

Upper and Lower human gastrointestinal tract

The upper gastrointestinal tract consists of the esophagus, stomach, and duodenum. The exact demarcation between the upper and lower tracts is the suspensory ligament of the duodenum (also known as the Ligament of Treitz). This delineates the embryological borders between the foregut and midgut, and is also the division commonly used by clinicians to describe gastrointestinal bleeding as being of "upper" or "lower" origin. Upon dissection, the duodenum may appear to be a unified organ, but it is divided into four segments based upon function, location, and internal anatomy. The four segments of the duodenum are as follows (starting at the stomach, and moving toward the jejunum): bulb, descending, horizontal, and ascending. The suspensory ligament attaches the superior border of the ascending duodenum to the diaphragm.

The suspensory muscle of duodenum is an important anatomical landmark which shows the formal division between the duodenum and the jejunum, the first and second parts of the small intestine, respectively.This is a thin muscle which is derived from the embryonic mesoderm.

Lower gastrointestinal tract

The lower gastrointestinal tract includes most of the small intestine and all of the large intestine.

• Bowel or intestine
  • Small Intestine: Has three parts:
    • Duodenum: Here the digestive juices from the pancreas (digestive enzymes) and hormones and the gall bladder (bile) mix. The digestive enzymes break down proteins and bile and emulsify fats into micelles. The duodenum contains Brunner's glands which produce a mucus-rich alkaline secretion containing bicarbonate , which In combination with bicarbonate from the pancreas neutralizes HCl of the stomach.
    • Jejunum: This is the midsection of the intestine, connecting the duodenum to the ileum. It contains the plicae circulares (also called circular folds or valves of Kerckring), and villi that increase the surface area of this part of the GI Tract. Products of digestion (sugars, amino acids, and fatty acids) are absorbed into the bloodstream here.
    • Ileum: Has villi similar to the jejunum, and absorbs mainly vitamin B12 and bile acids, as well as any other remaining nutrients.
  • Large Intestine: Has three parts:
    • Caecum: The vermiform appendix is attached to the caecum.
    • Colon: Includes the ascending colon, transverse colon, descending colon and sigmoid Flexure: The main function of the Colon is to absorb water, but it also contains bacteria that produce beneficial vitamins like vitamin K.
    • Rectum
    • Anal canal: The terminal part of the large intestine.

Development

The gut is an endoderm-derived structure. At approximately 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 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 can be divided 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 components of the definitive gut as well.

Each segment of the gut 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 of the primitive gut. In contrast, gut-related derivatives — that is, those structures that derive from the primitive gut but are not part of the gut proper, in general develop as out-pouchings of the primitive gut. The blood vessels supplying these structures remain constant throughout development.

Part	Part in adult	Gives rise to	Arterial supply
Foregut	Esophagus to first 2 sections of the duodenum	Esophagus, Stomach, Duodenum (1st and 2nd parts), Liver, Gallbladder, Pancreas, Superior portion of pancreas (Note that though the Spleen is supplied by the celiac trunk, it is derived from dorsal mesentery and therefore not a foregut derivative)	celiac trunk
Midgut	lower duodenum, to the first two-thirds of the transverse colon	lower duodenum, jejunum, ileum, cecum, appendix, ascending colon, and first two-third of the transverse colon	branches of the superior mesenteric artery
Hindgut	last third of the transverse colon, to the upper part of the anal canal	last third of the transverse colon, descending colon, rectum, and upper part of the anal canal	branches of the inferior mesenteric artery

Histology

Main article: Gastrointestinal wall

General structure of the gut wall

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:

• Mucosa
• Submucosa
• Muscularis externa (the external muscular layer)
• Adventitia or serosa

Mucosa

The mucosa is the innermost layer of the gastrointestinal tract. that is surrounding the lumen, or open space within the tube. This layer comes in direct contact with digested food (chyme). The mucosa is made up of:

• Epithelium - innermost layer. Responsible for most digestive, absorptive and secretory processes.
• Lamina propria - a layer of connective tissue. Unusually cellular compared to most connective tissue
• Muscularis mucosae - a thin layer of smooth muscle that aids the passing of material and enhances the interaction between the epithelial layer and the contents of the lumen by agitation and peristalsis.

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.

Submucosa

The submucosa consists of a dense irregular layer of connective tissue with large blood vessels, lymphatics, and nerves branching into the mucosa and muscularis externa. It contains Meissner's plexus, an enteric nervous plexus, situated on the inner surface of the muscularis externa.

Muscularis externa

The muscularis externa consists of an inner circular layer and a longitudinal outer muscular layer. The circular muscle layer prevents food from traveling backward and the longitudinal layer shortens the tract. The layers are not truly longitudinal or circular, rather 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.

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 is referred to as faeces.

Between the two muscle layers are the myenteric or Auerbach's plexus. This controls peristalsis. Activity is initiated by the pacemaker cells (interstitial cells of Cajal). The gut has intrinsic peristaltic activity (basal electrical rhythm) due to its self-contained enteric nervous system. The rate can of course be modulated by the rest of the autonomic nervous system.

Adventitia/serosa

The outermost layer of the GI 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 is 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, the oral cavity has adventitia.

Physiology

The time taken for food or other ingested objects to transit through the gastrointestinal tract varies depending on many factors, but roughly, it takes less than an hour after a meal for 50% of stomach contents to empty into the intestines and total emptying of the stomach takes around 2 hours. Subsequently, 50% emptying of the small intestine takes 1 to 2 hours. Finally, transit through the colon takes 12 to 50 hours with wide variation between individuals.

Immune function

The gastrointestinal tract is also a prominent part of the immune system. The surface area of the digestive tract is estimated to be the surface area of a football field. With such a large exposure, the immune system must work hard to prevent pathogens from entering into blood and lymph.^[WP:V]

The low pH (ranging from 1 to 4) of the stomach is fatal for many microorganisms that enter it. Similarly, mucus (containing IgA antibodies) neutralizes many of these microorganisms. Other factors in the GI tract help with immune function as well, including enzymes in saliva and bile. Enzymes such as Cyp3A4, along with the antiporter activities, also are instrumental in the intestine's role of detoxification of antigens and xenobiotics, such as drugs, involved in first pass metabolism.

Health-enhancing intestinal bacteria serve to prevent the overgrowth of potentially harmful bacteria in the gut. These two types of bacteria compete for space and "food," as there are limited resources within the intestinal tract. A ratio of 80-85% beneficial to 15-20% potentially harmful bacteria generally is considered normal within the intestines. Microorganisms also are kept at bay by an extensive immune system comprising the gut-associated lymphoid tissue (GALT).

Clinical relevance

Main article: Digestive disease

There are a number of diseases and conditions affecting the gastrointestinal system, including:

• Appendicitis
• Cancer
• Celiac Disease
• Cholera
• Colorectal cancer
• Diarrhoea
• Diverticulitis
• Enteric duplication cyst
• Gastroenteritis, also known as "stomach flu"; an inflammation of the stomach and intestines
• Giardiasis
• Inflammatory bowel disease (including Crohn's disease and ulcerative colitis)
• Irritable bowel syndrome
• Pancreatitis
• Peptic ulcer disease
• Yellow Fever

See also

This article uses anatomical terminology; for an overview, see anatomical terminology.

• Dysbiosis
• Gastrointestinal hormone
• Major systems of the human body

References

Additional images

• Illustration of Gastrointestinal Tract.

External links

• Pediatric Overview of Human Digestive System
• Anatomy atlas of the Digestive System
• Overview at Colorado State University
• Your Digestive System and How It Works at National Institutes of Health

UpToDate Contents

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• 1. 消化管の発達に関する概要 overview of the development of the gastrointestinal tract
• 2. 全身性エリテマトーデスの神経精神症状：原因および診断的アプローチ lower gastrointestinal bleeding in children causes and diagnostic approach
• 3. 成人における急性下部消化管出血に対するアプローチ approach to acute lower gastrointestinal bleeding in adults
• 4. 消化管間質腫瘍、平滑筋腫、および消化管の平滑筋肉腫の局所治療 local treatment for gastrointestinal stromal tumors leiomyomas and leiomyosarcomas of the gastrointestinal tract
• 5. 潜在性消化管出血の評価 evaluation of occult gastrointestinal bleeding

English Journal

• In vitro toxicity assessment of silver nanoparticles in the presence of phenolic compounds--preventive agents against the harmful effect?

• Martirosyan A1, Bazes A, Schneider YJ.Author information 1Institute of Life Sciences & UCLouvain, Laboratory of Cellular, Nutritional and Toxicological Biochemistry , Louvain-la-Neuve , Belgium.AbstractThe increasing commercial use of silver nanoparticles (Ag-NPs) will inevitably lead to elevated silver exposure and thus to potential human health complications. In this study the acute toxicity of Ag-NPs <20 nm alone and upon co-administration with food matrix component phenolic compounds (PCs) on the cell-based models of the gastrointestinal tract was investigated. An improved co-culture model of Caco-2 and RajiB cells was applied for more precise in vitro simulation of the gastrointestinal tract. The involvement of two major factors contributing to the toxicity of Ag-NPs, i.e. the release of Ag(+) and the induction of oxidative stress, was investigated. Ag-NPs were cytotoxic for Caco-2 cells with an EC50 of ca. 40 µg/ml. Ag-NPs led to oxidative stress starting from ca. 45 µg/ml. The epithelial barrier integrity disruption by Ag-NPs on Caco-2 cell mono- and co-cultures was established by decreased transepithelial electrical resistances and increased passages of Lucifer Yellow, a paracellular marker. Immunofluorescence staining demonstrated that Ag-NPs affect occludin and zonula occludens 1 distributions, suggesting the opening of tight junctions. Ag(+), corresponding to the release from Ag-NPs, demonstrated a partial contribution in the toxic parameters, induced by Ag-NPs. Two PCs, quercetin and kaempferol, partially protected the Caco-2 cells from Ag-NP-induced toxicity and maintained the epithelial barrier integrity, disrupted by NPs. No protective effect was observed for resveratrol. The protective effect could be beneficial and decrease the potential toxicity of ingested Ag-NPs. However, the precise mechanisms of barrier-integrity-destabilising action of Ag-NPs/Ag(+) and protective effect of PCs still require further elucidation.
• Nanotoxicology.Nanotoxicology.2014 Aug;8(5):573-82. doi: 10.3109/17435390.2013.812258. Epub 2013 Jun 27.
• The increasing commercial use of silver nanoparticles (Ag-NPs) will inevitably lead to elevated silver exposure and thus to potential human health complications. In this study the acute toxicity of Ag-NPs <20 nm alone and upon co-administration with food matrix component phenolic compounds (PCs)
• PMID 23738887

• Bound phenolics in foods, a review.

• Acosta-Estrada BA1, Gutiérrez-Uribe JA2, Serna-Saldívar SO1.Author information 1Centro de Biotecnología-FEMSA, School of Biotechnology and Foods, Tecnológico de Monterrey-Campus Monterrey, Av. Eugenio Garza Sada 2501, Monterrey, N.L. C.P. 64849, Mexico.2Centro de Biotecnología-FEMSA, School of Biotechnology and Foods, Tecnológico de Monterrey-Campus Monterrey, Av. Eugenio Garza Sada 2501, Monterrey, N.L. C.P. 64849, Mexico. Electronic address: jagu@itesm.mx.AbstractAmong phytochemicals, phenolic compounds have been extensively researched due to their diverse health benefits. Phenolic compounds occur mostly as soluble conjugates and insoluble forms, covalently bound to sugar moieties or cell wall structural components. Absorption mechanisms for bound phenolic compounds in the gastrointestinal tract greatly depend on the liberation of sugar moieties. Food processes such as fermentation, malting, thermoplastic extrusion or enzymatic, alkaline and acid hydrolyses occasionally assisted with microwave or ultrasound have potential to release phenolics associated to cell walls. Different kinds of wet chemistry methodologies to release and detect bound phenolic have been developed. These include harsh heat treatments, chemical modifications or biocatalysis. New protocols for processing and determining phenolics in food matrices must be devised in order to release bound phenolics and for quality control in the growing functional food industry.
• Food chemistry.Food Chem.2014 Jun 1;152:46-55. doi: 10.1016/j.foodchem.2013.11.093. Epub 2013 Nov 27.
• Among phytochemicals, phenolic compounds have been extensively researched due to their diverse health benefits. Phenolic compounds occur mostly as soluble conjugates and insoluble forms, covalently bound to sugar moieties or cell wall structural components. Absorption mechanisms for bound phenolic c
• PMID 24444905

• Role of enteric neurotransmission in host defense and protection of the gastrointestinal tract.

• Sharkey KA1, Savidge TC2.Author information 1Hotchkiss Brain Institute and Snyder Institute for Chronic Diseases, Department of Physiology & Pharmacology, University of Calgary, Calgary, Alberta, Canada. Electronic address: ksharkey@ucalgary.ca.2Texas Children's Microbiome Center, Department of Pathology and Immunology, Baylor College of Medicine, Houston, TX, USA.AbstractHost defense is a vital role played by the gastrointestinal tract. As host to an enormous and diverse microbiome, the gut has evolved an elaborate array of chemical and physicals barriers that allow the digestion and absorption of nutrients without compromising the mammalian host. The control of such barrier functions requires the integration of neural, humoral, paracrine and immune signaling, involving redundant and overlapping mechanisms to ensure, under most circumstances, the integrity of the gastrointestinal epithelial barrier. Here we focus on selected recent developments in the autonomic neural control of host defense functions used in the protection of the gut from luminal agents, and discuss how the microbiota may potentially play a role in enteric neurotransmission. Key recent findings include: the important role played by subepithelial enteric glia in modulating intestinal barrier function, identification of stress-induced mechanisms evoking barrier breakdown, neural regulation of epithelial cell proliferation, the role of afferent and efferent vagal pathways in regulating barrier function, direct evidence for bacterial communication to the enteric nervous system, and microbial sources of enteric neurotransmitters. We discuss these new and interesting developments in our understanding of the role of the autonomic nervous system in gastrointestinal host defense.
• Autonomic neuroscience : basic & clinical.Auton Neurosci.2014 Apr;181C:94-106. doi: 10.1016/j.autneu.2013.12.006. Epub 2013 Dec 22.
• Host defense is a vital role played by the gastrointestinal tract. As host to an enormous and diverse microbiome, the gut has evolved an elaborate array of chemical and physicals barriers that allow the digestion and absorption of nutrients without compromising the mammalian host. The control of suc
• PMID 24412639

Japanese Journal

• Regression of Follicular Lymphoma of the Duodenum Following Eradication of H. pylori Infection

• Hayashi Hiroki,Onishi Yutaka,Mitsuoka Hiroshi,Ogura Takeshi,Maeda Mitsuo,Nishigami Takashi,Harada Masaru
• Internal Medicine 52(23), 2611-2614, 2013
• … A 64-year-old woman was referred for an examination of the upper gastrointestinal (GI) tract. …
• NAID 130003383714

• 上部消化管の内科的処置後に環境菌由来グラム陰性桿菌による菌血症を認めた2症例

• 濱田 洋平,草場 耕二,曲渕 裕樹,金子 ゆかり,永田 正喜,福岡 麻美,永沢 善三,青木 洋介
• 日本環境感染学会誌 28(2), 109-113, 2013
•   上部消化管の内科的処置後に環境菌由来グラム陰性桿菌による菌血症を認めた2症例を経験した．症例1は頸部食道癌患者で胃管の挿入手技後にEnterobacter cloacaeによる菌血症を認めた．症例2は食道静脈瘤に対して内視鏡的静脈瘤結紮術および内視鏡的硬化療法の施行後に，それぞれE. cloacae, Asaia lannensisによる菌血症の2エピソードを認めた．上部消化管の内科的処置後に …
• NAID 130003371166

• Increased Risk of Gastrointestinal Malignancy in Patients with Diabetes Mellitus and Correlations with Anti-Diabetes Drugs: A Nationwide Population-based Study in Taiwan

• Chiu Chun-Chih,Huang Chin-Chou,Chen Yu-Chun,Chen Tzeng-Ji,Liang Ying,Lin Shing-Jong,Chen Jaw-Wen,Leu Hsin-Bang,Chan Wan-Leong
• Internal Medicine 52(9), 939-946, 2013
• … However, whether DM is associated with an increased risk of cancer of the digestive tract remains undetermined. … Methods From 2000 to 2007, a study cohort consisting of 39,515 patients with newly diagnosed diabetes without a previous diagnosis of gastrointestinal (GI) cancer was identified from the National Health Insurance Research Database in Taiwan. …
• NAID 130003366011

Related Links

• GI tract - definition of GI tract in the Medical dictionary - by ...

GI tract, abbreviation for gastrointestinal tract. See digestive tract. non-cardiac chest pain Internal medicine Chest pain that simulates cardiac nosologies, but is unrelated to cardiovascular disease; 50% of Pts with NCCP have known ...

• GI Tract Examiner

GI Tract Examiner attended Digestive Disease Week (DDW) 2012, where physicians and researchers met in San Diego to share the latest in gastrointestinal research, medicine, and technology. Here, we highlight the most compelling ...

• GI tract - definition of GI tract by the Free Online Dictionary ...

Thesaurus Legend: Synonyms Related Words Antonyms Noun 1. GI tract - tubular passage of mucous membrane and muscle extending about 8.3 meters from mouth to anus; functions in digestion and elimination alimentary canal, alimentary tract ...

Related Pictures

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★リンクテーブル★

リンク元	「消化管」「gastrointestinal」
拡張検索	「lower GI tract」
関連記事	「GI」「tracing」「G」「tract」

「消化管」

　　[★]

英

gastrointestinal tract, GI tract

英

alimentary tract

関

消化器系

以下の総称：食道、胃、小腸、大腸

消化管の構造

• 粘膜上皮、基底膜、粘膜固有層、粘膜筋板(胆嚢ではこれを欠く)、粘膜下組織/粘膜下層(胆嚢ではこれを欠く)、筋層、(漿膜下組織)、漿膜/外膜(食道、直腸で欠く)

運動

• 蠕動運動：食塊を肛門側に1cm/sで送り出す：胃・食道・小腸・近位結腸・遠位結腸・直腸
• 分節運動：分節を作ってくびれて食塊を混和：小腸・近位結腸
• 振子運動：縦走筋の収縮により腸管を縦方向に収縮させる：小腸・近位結腸・(遠位結腸・直腸)

「gastrointestinal」

　　[★]

• adj.

• 胃腸の、胃腸管の、胃腸管系の
• 消化管の、消化器の、消化器系の

関

alimentary canal、alimentary system、alimentary tract、digestive organ、digestive system、digestive tract、gastrointestinal system、gastrointestinal tract、GI、GI tract、intestinal

　 　

「lower GI tract」

　　[★]

• 下部消化管

関

lower gastrointestinal tract

「GI」

　　[★]

• adj.

• 胃腸の、消化管の、消化器系の、胃腸管系の

• glycemic index 血糖上昇速度、血糖上昇率

関

alimentary canal、alimentary system、alimentary tract、digestive system、digestive tract、gastrointestinal、gastrointestinal system、gastrointestinal tract、GI tract、intestinal

　

「tracing」

　　[★]

• n.

• 追跡

関

chase、follow up、follow-up、pursue、pursuit、trace

　 　 　 　

「G」

　　[★]

• グアニン guanine
• グアノシン guanosine
• グリシン glycine

　

「tract」

　　[★]

• n.

• 路

関

tractus