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The duodenum is the first section of the
small intestine The small intestine or small bowel is an organ (anatomy), organ in the human gastrointestinal tract, gastrointestinal tract where most of the #Absorption, absorption of nutrients from food takes place. It lies between the stomach and large intes ...
in most
vertebrates Vertebrates () are animals with a vertebral column (backbone or spine), and a cranium, or skull. The vertebral column surrounds and protects the spinal cord, while the cranium protects the brain. The vertebrates make up the subphylum Vertebra ...
, including
mammals A mammal () is a vertebrate animal of the class Mammalia (). Mammals are characterised by the presence of milk-producing mammary glands for feeding their young, a broad neocortex region of the brain, fur or hair, and three middle e ...
, reptiles, and
birds Birds are a group of warm-blooded vertebrates constituting the class (biology), class Aves (), characterised by feathers, toothless beaked jaws, the Oviparity, laying of Eggshell, hard-shelled eggs, a high Metabolism, metabolic rate, a fou ...
. In mammals, it may be the principal site for
iron Iron is a chemical element; it has symbol Fe () and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, forming much of Earth's o ...
absorption. The duodenum precedes the
jejunum The jejunum is the second part of the small intestine in humans and most higher vertebrates, including mammals, reptiles, and birds. Its lining is specialized for the absorption by enterocytes of small nutrient molecules which have been pr ...
and
ileum The ileum () is the final section of the small intestine in most higher vertebrates, including mammals, reptiles, and birds. In fish, the divisions of the small intestine are not as clear and the terms posterior intestine or distal intestine may ...
and is the shortest part of the small intestine. In humans, the duodenum is a hollow jointed tube about long connecting the
stomach The stomach is a muscular, hollow organ in the upper gastrointestinal tract of Human, humans and many other animals, including several invertebrates. The Ancient Greek name for the stomach is ''gaster'' which is used as ''gastric'' in medical t ...
to the jejunum, the middle part of the small intestine. It begins with the duodenal bulb, and ends at the duodenojejunal flexure marked by the suspensory muscle of duodenum. The duodenum can be divided into four parts: the first (superior), the second (descending), the third (transverse) and the fourth (ascending) parts.


Overview

The duodenum is the first section of the
small intestine The small intestine or small bowel is an organ (anatomy), organ in the human gastrointestinal tract, gastrointestinal tract where most of the #Absorption, absorption of nutrients from food takes place. It lies between the stomach and large intes ...
in most higher vertebrates, including
mammals A mammal () is a vertebrate animal of the class Mammalia (). Mammals are characterised by the presence of milk-producing mammary glands for feeding their young, a broad neocortex region of the brain, fur or hair, and three middle e ...
, reptiles, and
birds Birds are a group of warm-blooded vertebrates constituting the class (biology), class Aves (), characterised by feathers, toothless beaked jaws, the Oviparity, laying of Eggshell, hard-shelled eggs, a high Metabolism, metabolic rate, a fou ...
. In
fish A fish (: fish or fishes) is an aquatic animal, aquatic, Anamniotes, anamniotic, gill-bearing vertebrate animal with swimming fish fin, fins and craniate, a hard skull, but lacking limb (anatomy), limbs with digit (anatomy), digits. Fish can ...
, the divisions of the small intestine are not as clear, and the terms ''anterior intestine'' or ''proximal intestine'' may be used instead of duodenum. In mammals the duodenum may be the principal site for
iron Iron is a chemical element; it has symbol Fe () and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, forming much of Earth's o ...
absorption. In humans, the duodenum is a C-shaped hollow jointed tube, in length, lying adjacent to the
stomach The stomach is a muscular, hollow organ in the upper gastrointestinal tract of Human, humans and many other animals, including several invertebrates. The Ancient Greek name for the stomach is ''gaster'' which is used as ''gastric'' in medical t ...
(and connecting it to the small intestine). It is divided anatomically into four sections. The first part lies within the
peritoneum The peritoneum is the serous membrane forming the lining of the abdominal cavity or coelom in amniotes and some invertebrates, such as annelids. It covers most of the intra-abdominal (or coelomic) organs, and is composed of a layer of mesotheli ...
but its other parts are
retroperitoneal The retroperitoneal space (retroperitoneum) is the anatomical space (sometimes a potential space) behind (''retro'') the peritoneum. It has no specific delineating anatomical structures. Organs are retroperitoneal if they have peritoneum on thei ...
.


Parts

The ''first'' or ''superior part'' of the duodenum is a continuation from the pylorus to the transpyloric plane. It is superior (above) to the rest of the segments, at the
vertebral Each vertebra (: vertebrae) is an irregular bone with a complex structure composed of bone and some hyaline cartilage, that make up the vertebral column or spine, of vertebrates. The proportions of the vertebrae differ according to their spina ...
level of L1. The duodenal bulb, about long, is the first part of the duodenum and is slightly dilated. The duodenal bulb is a remnant of the mesoduodenum, a
mesentery In human anatomy, the mesentery is an Organ (anatomy), organ that attaches the intestines to the posterior abdominal wall, consisting of a double fold of the peritoneum. It helps (among other functions) in storing Adipose tissue, fat and allowi ...
that suspends the organ from the posterior abdominal wall in fetal life. The first part of the duodenum is mobile, and connected to the liver by the hepatoduodenal ligament of the lesser omentum. The first part of the duodenum ends at the corner, the ''superior duodenal flexure''. Relations: * Anterior **
Gallbladder In vertebrates, the gallbladder, also known as the cholecyst, is a small hollow Organ (anatomy), organ where bile is stored and concentrated before it is released into the small intestine. In humans, the pear-shaped gallbladder lies beneath t ...
** Quadrate lobe of liver * Posterior **
Bile duct A bile duct is any of a number of long tube-like structures that carry bile, and is present in most vertebrates. The bile duct is separated into three main parts: the fundus (superior), the body (middle), and the neck (inferior). Bile is requ ...
** Gastroduodenal artery **
Portal vein The portal vein or hepatic portal vein (HPV) is a blood vessel that carries blood from the gastrointestinal tract, gallbladder, pancreas and spleen to the liver. This blood contains nutrients and toxins extracted from digested contents. Approxima ...
**
Inferior vena cava The inferior vena cava is a large vein that carries the deoxygenated blood from the lower and middle body into the right atrium of the heart. It is formed by the joining of the right and the left common iliac veins, usually at the level of the ...
** Head of pancreas * Superior ** Neck of gallbladder ** Hepatoduodenal ligament ( lesser omentum) * Inferior ** Neck of pancreas **
Greater omentum Greater may refer to: *Greatness, the state of being great *Greater than, in inequality * ''Greater'' (film), a 2016 American film *Greater (flamingo), the oldest flamingo on record * "Greater" (song), by MercyMe, 2014 * Greater Bank, an Australi ...
** Head of pancreas The ''second'' or ''descending part'' of the duodenum begins at the superior duodenal flexure. It goes inferior to the lower border of vertebral body L3, before making a sharp turn medially into the ''inferior duodenal flexure'', the end of the descending part. The pancreatic duct and common bile duct enter the descending duodenum, through the major duodenal papilla. The second part of the duodenum also contains the minor duodenal papilla, the entrance for the accessory pancreatic duct. The junction between the embryological
foregut The foregut in humans is the anterior part of the alimentary canal, from the distal esophagus to the first half of the duodenum, at the entrance of the bile duct. Beyond the stomach, the foregut is attached to the abdominal walls by mesentery. ...
and
midgut The midgut is the portion of the human embryo from which almost all of the small intestine and approximately half of the large intestine develop. After it bends around the superior mesenteric artery, it is called the "midgut loop". It comprises ...
lies just below the major duodenal papilla. The ''third'', ''horizontal'' or ''inferior part'' of the duodenum is 10~12 cm in length. It begins at the ''inferior duodenal flexure'' and passes transversely to the left, passing in front of the
inferior vena cava The inferior vena cava is a large vein that carries the deoxygenated blood from the lower and middle body into the right atrium of the heart. It is formed by the joining of the right and the left common iliac veins, usually at the level of the ...
, abdominal aorta and the
vertebral column The spinal column, also known as the vertebral column, spine or backbone, is the core part of the axial skeleton in vertebrates. The vertebral column is the defining and eponymous characteristic of the vertebrate. The spinal column is a segmente ...
. The superior mesenteric artery and
vein Veins () are blood vessels in the circulatory system of humans and most other animals that carry blood towards the heart. Most veins carry deoxygenated blood from the tissues back to the heart; exceptions are those of the pulmonary and feta ...
are
anterior Standard anatomical terms of location are used to describe unambiguously the anatomy of humans and other animals. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position pro ...
to the third part of the duodenum. This part may be compressed between the aorta and SMA causing superior mesenteric artery syndrome. The ''fourth'' or ''ascending part'' of the duodenum passes upward, joining with the
jejunum The jejunum is the second part of the small intestine in humans and most higher vertebrates, including mammals, reptiles, and birds. Its lining is specialized for the absorption by enterocytes of small nutrient molecules which have been pr ...
at the duodenojejunal flexure. The fourth part of the duodenum is at the vertebral level L3, and may pass directly on top, or slightly to the left, of the
aorta The aorta ( ; : aortas or aortae) is the main and largest artery in the human body, originating from the Ventricle (heart), left ventricle of the heart, branching upwards immediately after, and extending down to the abdomen, where it splits at ...
.


Blood supply

The first (superior) part of the duodenum, right after the pylorus of the stomach, is not supplied by the arcades. Instead, it is supplied by the supraduodenal artery and posterior superior pancreaticoduodenal artery, along with some branches of the right gastroepiploic artery and the anterior superior pancreaticoduodenal artery. In many people part of the first centimeter of the duodenum is also supplied by branches of the
right gastric artery The right gastric artery usually arises from the proper hepatic artery. It descends to the pyloric end of the stomach The stomach is a muscular, hollow organ in the upper gastrointestinal tract of Human, humans and many other animals, includ ...
. The remaining three parts (descending, horizontal, and ascending) of the duodenum are supplied by two arcades (rings) of arteries, one anterior (in front) of the duodenum and pancreas and one posterior to (behind) them. Each arcade is made of two anastomosed (connected) arteries. The superior artery of each arcade comes from the superior pancreaticoduodenal artery, which arises from the celiac artery via the gastroduodenal artery. The inferior artery of each arcade comes from the inferior pancreaticoduodenal artery, a branch of the superior mesenteric artery. The anterior arcade is formed by the anterior superior pancreaticoduodenal artery and the anterior inferior pancreaticoduodenal artery; the posterior arcade is formed by the posterior superior pancreaticoduodenal artery and the posterior inferior pancreaticoduodenal artery. Vessels from the arcades supply the muscularis externa (muscular layer) before forming a plexus (network of blood vessels) in the submucosa (a layer of connective tissue) called the submucosal plexus. Vessels continue from the submucosal plexus through the muscularis mucosae (another thin muscular layer) before forming another plexus under the
epithelium Epithelium or epithelial tissue is a thin, continuous, protective layer of cells with little extracellular matrix. An example is the epidermis, the outermost layer of the skin. Epithelial ( mesothelial) tissues line the outer surfaces of man ...
of the villi, the layer where nutrients are absorbed. These vessels entering the duodenum from the arcades are sometimes called vasae rectae or arteriae rectae. The venous drainage of the duodenum mainly follows the arteries, ultimately draining into the portal system. The venous arcades are usually superficial to the arterial arcades. The anterior superior pancreaticoduodenal vein drains into the
right gastroepiploic vein The right gastroepiploic vein (right gastroomental vein) is a blood vessel that drains blood from the greater curvature and left part of the body of the stomach into the superior mesenteric vein. It runs from left to right along the greater curva ...
, as do the veins of the lower first part of the duodenum and the pylorus (subpyloric veins). The upper first part of the duodenum is drained by suprapyloric veins, which can drain into the
portal vein The portal vein or hepatic portal vein (HPV) is a blood vessel that carries blood from the gastrointestinal tract, gallbladder, pancreas and spleen to the liver. This blood contains nutrients and toxins extracted from digested contents. Approxima ...
or the posterior superior pancreaticoduodenal vein, which drains into the portal vein. The inferior veins of the arcades drain into the superior mesenteric, inferior mesenteric, splenic, or first jejunal vein. Embryologically, the duodenum arises from both the
foregut The foregut in humans is the anterior part of the alimentary canal, from the distal esophagus to the first half of the duodenum, at the entrance of the bile duct. Beyond the stomach, the foregut is attached to the abdominal walls by mesentery. ...
and
midgut The midgut is the portion of the human embryo from which almost all of the small intestine and approximately half of the large intestine develop. After it bends around the superior mesenteric artery, it is called the "midgut loop". It comprises ...
, constituting the boundary between the two. However, the "midgut" is defined surgically as the parts of the intestine supplied by the superior mesenteric artery. Since the duodenum is supplied both by the celiac artery and the superior mesenteric artery, these two definitions are similar but not exactly the same.


Lymphatic drainage

The lymphatic vessels follow the arteries in a retrograde fashion. The anterior lymphatic vessels drain into the pancreatoduodenal
lymph node A lymph node, or lymph gland, is a kidney-shaped organ of the lymphatic system and the adaptive immune system. A large number of lymph nodes are linked throughout the body by the lymphatic vessels. They are major sites of lymphocytes that includ ...
s located along the superior and inferior pancreatoduodenal arteries and then into the pyloric lymph nodes (along the gastroduodenal artery). The posterior lymphatic vessels pass posterior to the head of the pancreas and drain into the superior mesenteric lymph nodes. Efferent lymphatic vessels from the duodenal lymph nodes ultimately pass into the celiac lymph nodes.


Histology

Under
microscopy Microscopy is the technical field of using microscopes to view subjects too small to be seen with the naked eye (objects that are not within the resolution range of the normal eye). There are three well-known branches of microscopy: optical mic ...
, the duodenum has a villous mucosa. This is distinct from the mucosa of the pylorus, which directly joins the duodenum. Like other structures of the
gastrointestinal tract The gastrointestinal tract (GI tract, digestive tract, alimentary canal) is the tract or passageway of the Digestion, digestive system that leads from the mouth to the anus. The tract is the largest of the body's systems, after the cardiovascula ...
, the duodenum has a mucosa, submucosa, muscularis externa, and adventitia. Glands line the duodenum, known as
Brunner's gland Brunner's glands (or duodenal glands) are compound tubuloalveolar submucosal glands found in that portion of the duodenum proximal to the hepatopancreatic sphincter (i.e sphincter of Oddi). For decades, it was believed that the main function o ...
s, which secrete
mucus Mucus (, ) is a slippery aqueous secretion produced by, and covering, mucous membranes. It is typically produced from cells found in mucous glands, although it may also originate from mixed glands, which contain both Serous fluid, serous and muc ...
and
bicarbonate In inorganic chemistry, bicarbonate (IUPAC-recommended nomenclature: hydrogencarbonate) is an intermediate form in the deprotonation of carbonic acid. It is a polyatomic anion with the chemical formula . Bicarbonate serves a crucial bioche ...
in order to neutralise stomach acids. These are distinct glands not found in the ileum or jejunum, the other parts of the small intestine. File:Dogduodenum100x3.jpg, Dog duodenum 100X Image:Small bowel duodenum with amyloid deposition congo red 10X.jpg, Duodenum with amyloid deposition in lamina propria Image:Gray1058.png, Section of duodenum of cat. X 60 Image:Giardiasis duodenum low.jpg ,
Micrograph A micrograph is an image, captured photographically or digitally, taken through a microscope or similar device to show a magnify, magnified image of an object. This is opposed to a macrograph or photomacrograph, an image which is also taken ...
showing giardiasis on a duodenal biopsy (
H&E stain Hematoxylin and eosin stain ( or haematoxylin and eosin stain or hematoxylin–eosin stain; often abbreviated as H&E stain or HE stain) is one of the principal tissue stains used in histology. It is the most widely used stain in medical diag ...
) Image:Microvilli-Duodenum.JPG, Duodenum with brush border (
microvillus Microvilli (: microvillus) are microscopic cellular membrane protrusions that increase the surface area for diffusion and minimize any increase in volume, and are involved in a wide variety of functions, including absorption, secretion, cellula ...
)


Variation

The duodenum's close anatomical association with the pancreas creates differences in function based on the position and orientation of the organs. The congenital abnormality, annular pancreas, causes a portion of the pancreas to encircle the duodenum. In an extramural annular pancreas, the pancreatic duct encircles the duodenum which results in gastrointestinal obstruction. An intramural annular pancreas is characterized by pancreatic tissue that is fused with the duodenal wall, causing duodenal ulceration.


Gene and protein expression

About 20,000 protein coding genes are expressed in human cells and 70% of these genes are expressed in the normal duodenum. Some 300 of these genes are more specifically expressed in the duodenum with very few genes expressed only in the duodenum. The corresponding specific proteins are expressed in the duodenal mucosa, and many of these are also expressed in the small intestine, such as alanine aminopeptidase, a digestive enzyme,
angiotensin-converting enzyme Angiotensin-converting enzyme (), or ACE, is a central component of the renin–angiotensin system (RAS), which controls blood pressure by regulating the volume of fluids in the body. It converts the hormone angiotensin I to the active vasocon ...
, involved in controlling
blood pressure Blood pressure (BP) is the pressure of Circulatory system, circulating blood against the walls of blood vessels. Most of this pressure results from the heart pumping blood through the circulatory system. When used without qualification, the term ...
, and RBP2, a protein involved in the uptake of
vitamin A Vitamin A is a fat-soluble vitamin that is an essential nutrient. The term "vitamin A" encompasses a group of chemically related organic compounds that includes retinol, retinyl esters, and several provitamin (precursor) carotenoids, most not ...
.


Function

The duodenum is largely responsible for the breakdown of food in the small intestine, using
enzymes An enzyme () is a protein that acts as a biological catalyst by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as pro ...
. The duodenum also regulates the rate of emptying of the stomach via hormonal pathways. Secretin and cholecystokinin are released from cells in the duodenal
epithelium Epithelium or epithelial tissue is a thin, continuous, protective layer of cells with little extracellular matrix. An example is the epidermis, the outermost layer of the skin. Epithelial ( mesothelial) tissues line the outer surfaces of man ...
in response to acidic and fatty stimuli present there when the pylorus opens and emits gastric
chyme Chyme or chymus (; ) is the semi-fluid mass of partly digested food that is expelled by the stomach, through the pyloric valve, into the duodenum (the beginning of the small intestine). Chyme results from the mechanical and chemical breakdown ...
into the duodenum for further digestion. These cause the
liver The liver is a major metabolic organ (anatomy), organ exclusively found in vertebrates, which performs many essential biological Function (biology), functions such as detoxification of the organism, and the Protein biosynthesis, synthesis of var ...
and
gallbladder In vertebrates, the gallbladder, also known as the cholecyst, is a small hollow Organ (anatomy), organ where bile is stored and concentrated before it is released into the small intestine. In humans, the pear-shaped gallbladder lies beneath t ...
to release
bile Bile (from Latin ''bilis''), also known as gall, is a yellow-green/misty green fluid produced by the liver of most vertebrates that aids the digestion of lipids in the small intestine. In humans, bile is primarily composed of water, is pro ...
, and the
pancreas The pancreas (plural pancreases, or pancreata) is an Organ (anatomy), organ of the Digestion, digestive system and endocrine system of vertebrates. In humans, it is located in the abdominal cavity, abdomen behind the stomach and functions as a ...
to release bicarbonate and digestive enzymes such as
trypsin Trypsin is an enzyme in the first section of the small intestine that starts the digestion of protein molecules by cutting long chains of amino acids into smaller pieces. It is a serine protease from the PA clan superfamily, found in the dig ...
,
lipase In biochemistry, lipase ( ) refers to a class of enzymes that catalyzes the hydrolysis of fats. Some lipases display broad substrate scope including esters of cholesterol, phospholipids, and of lipid-soluble vitamins and sphingomyelinases; howe ...
and
amylase An amylase () is an enzyme that catalysis, catalyses the hydrolysis of starch (Latin ') into sugars. Amylase is present in the saliva of humans and some other mammals, where it begins the chemical process of digestion. Foods that contain large ...
into the duodenum as they are needed. The duodenum is a critical contributor to the regulation of food intake and glycemic control. As the first part of the small intestine, the duodenum is the initial site of nutrient absorption in the gastrointestinal tract. The duodenum senses nutrient intake and composition, and signals to the liver, pancreas, adipose tissue and brain through the direct and indirect release of several key hormones and signaling molecules, including the
incretin Incretins are a group of metabolic hormones that decrease Blood sugar level, blood glucose levels. Incretins are released after eating and augment the secretion of insulin released from Pancreas, pancreatic beta cells of the islets of Langerhans ...
peptides Glucose-dependent insulinotropic polypeptide (GIP) and Glucagon-like peptide-1 (GLP-1), as well as Cholecystokinin (CCK) and Secretin.  The duodenum also signals to the brain directly via vagal afferents enabling neural control over food intake and glycemia.  Intestinal secretion of GIP and GLP-1 stimulates glucose-dependent insulin secretion from pancreatic beta-cells, known as the incretin effect. Incretin peptides, principally GLP-1 and GIP, regulate islet hormone secretion, glucose concentrations, lipid metabolism, gut motility, appetite and body weight, and immune function. The villi of the duodenum have a leafy-looking appearance, which is a histologically identifiable structure.
Brunner's glands Brunner's glands (or duodenal glands) are compound tubuloalveolar submucosal glands found in that portion of the duodenum proximal to the hepatopancreatic sphincter (i.e sphincter of Oddi). For decades, it was believed that the main function of ...
, which secrete
mucus Mucus (, ) is a slippery aqueous secretion produced by, and covering, mucous membranes. It is typically produced from cells found in mucous glands, although it may also originate from mixed glands, which contain both Serous fluid, serous and muc ...
, are only found in the duodenum. The duodenum wall consists of a very thin layer of cells that form the muscularis mucosae.


Clinical significance


Ulceration

Ulcers of the duodenum commonly occur because of infection by the bacteria '' Helicobacter pylori''. These bacteria, through a number of mechanisms, erode the protective mucosa of the duodenum, predisposing it to damage from gastric acids. The first part of the duodenum is the most common location of ulcers since it is where the acidic chyme meets the duodenal mucosa before mixing with the alkaline secretions of the duodenum. Duodenal ulcers may cause recurrent abdominal pain and
dyspepsia Indigestion, also known as dyspepsia or upset stomach, is a condition of impaired digestion. Symptoms may include upper abdominal fullness, heartburn, nausea, belching, or upper abdominal pain. People may also experience feeling full earlier ...
, and are often investigated using a urea breath test to test for the bacteria, and
endoscopy An endoscopy is a procedure used in medicine to look inside the body. The endoscopy procedure uses an endoscope to examine the interior of a hollow organ or cavity of the body. Unlike many other medical imaging techniques, endoscopes are insert ...
to confirm ulceration and take a
biopsy A biopsy is a medical test commonly performed by a surgeon, interventional radiologist, an interventional radiologist, or an interventional cardiology, interventional cardiologist. The process involves the extraction of sampling (medicine), sample ...
. If managed, these are often managed through
antibiotic An antibiotic is a type of antimicrobial substance active against bacteria. It is the most important type of antibacterial agent for fighting pathogenic bacteria, bacterial infections, and antibiotic medications are widely used in the therapy ...
s that aim to eradicate the bacteria, and proton-pump inhibitors and
antacid An antacid is a substance which neutralization (chemistry), neutralizes gastric acid, stomach acidity and is used to relieve heartburn, indigestion, or an upset stomach. Some antacids have been used in the treatment of constipation and diarrhe ...
s to reduce the gastric acidity.


Celiac disease

The British Society of Gastroenterology guidelines specify that a duodenal biopsy is required for the diagnosis of adult
celiac disease Coeliac disease (British English) or celiac disease (American English) is a long-term autoimmune disorder, primarily affecting the small intestine. Patients develop intolerance to gluten, which is present in foods such as wheat, rye, spel ...
. The biopsy is ideally performed at a moment when the patient is on a gluten-containing diet.


Cancer

Duodenal cancer is a cancer in the first section of the small intestine. Cancer of the duodenum is relatively rare compared to
stomach cancer Stomach cancer, also known as gastric cancer, is a malignant tumor of the stomach. It is a cancer that develops in the Gastric mucosa, lining of the stomach. Most cases of stomach cancers are gastric carcinomas, which can be divided into a numb ...
and
colorectal cancer Colorectal cancer (CRC), also known as bowel cancer, colon cancer, or rectal cancer, is the development of cancer from the Colon (anatomy), colon or rectum (parts of the large intestine). Signs and symptoms may include Lower gastrointestinal ...
; malignant tumors in the duodenum constitute only around 0.3% of all the gastrointestinal tract tumors but around half of cancerous tissues that develop in the small intestine. Its histology is often observed to be adenocarcinoma, meaning that the cancerous tissue arises from glandular cells in the
epithelial tissue Epithelium or epithelial tissue is a thin, continuous, protective layer of cells with little extracellular matrix. An example is the epidermis, the outermost layer of the skin. Epithelial ( mesothelial) tissues line the outer surfaces of man ...
lining the duodenum.


Obesity and diabetes

A western diet induces duodenal mucosal hyperplasia and dysfunction that underlie insulin resistance, type 2 diabetes and obesity. Diet-induced duodenal mucosal hyperplasia consists of increased mucosal mass, increased villus length, decreased crypt density, proliferation of enteroendocrine cells, increased enterocyte mass, and an accumulation of lipid droplets in the mucosa. Diet induced duodenal dysfunction includes increased duodenal nutrient absorption, altered duodenal hormone secretion, and altered intestinal vagal afferent neuronal function.


Inflammation

Inflammation of the duodenum is referred to as duodenitis. There are multiple known causes. Celiac disease and inflammatory bowel disease are two of the known causes.


Etymology

The name ''duodenum'' is
Medieval Latin Medieval Latin was the form of Literary Latin used in Roman Catholic Church, Roman Catholic Western Europe during the Middle Ages. It was also the administrative language in the former Western Roman Empire, Roman Provinces of Mauretania, Numidi ...
, short for ''intestīnum duodēnum digitōrum'', meaning "intestine of twelve finger-widths (in length)", genitive of ''duodēnī'', "twelve each", (related to ''duodecim'' "twelve"). Coined by Gerard of Cremona (d. 1187) in his Latin translation of "Canon Avicennae", "اثنا عشر" itself a loan-translation of Greek dodekadaktylon (δωδεκάδάκτυλον), literally "twelve fingers long". The intestine part was so called by the Greek physician Herophilus (c. 335–280 BCE) for its length, about equal to the breadth of 12 fingers. Many languages use
calque In linguistics, a calque () or loan translation is a word or phrase borrowed from another language by literal word-for-word or root-for-root translation. When used as a verb, "to calque" means to borrow a word or phrase from another language ...
s for this word. For example, German , Dutch and Turkish .


Additional images

File:Blausen 0817 SmallIntestine Anatomy.png, Sections of the small intestine Image:Gray533.png, The celiac artery and its branches; the stomach has been raised and the peritoneum removed Image:Gray1041.png , Superior and inferior duodenal fossæ Image:Gray1042.png, Duodenojejunal fossa Image:Gray1099.png, The pancreas and duodenum from behind Image:Gray1097.png, Transverse section through the middle of the first lumbar vertebra, showing the relations of the pancreas Image:Gray1100.png, The pancreatic duct Image:Illu pancrease.jpg, Region of pancreas File:Slide3ii.JPG, Duodenum File:Slide2ffff.JPG, Duodenum File:Slide7ffff.JPG, Duodenum


See also

*
Pancreas The pancreas (plural pancreases, or pancreata) is an Organ (anatomy), organ of the Digestion, digestive system and endocrine system of vertebrates. In humans, it is located in the abdominal cavity, abdomen behind the stomach and functions as a ...
* Choledochoduodenostomy - a surgical procedure to create a connection between the common bile duct (CBD) and an alternative portion of the duodenum.


References


External links


Duodenum
at th
Human Protein Atlas
* {{Authority control Digestive system Small intestine