pancreas

(păn`krēəs), glandular organ that secretes digestive enzymes and hormones. In humans, the pancreas is a yellowish organ about 7 in. (17.8 cm) long and 1.5 in. (3.8 cm) wide. It lies beneath the stomach and is connected to the small intestineintestine,
muscular hoselike portion of the gastrointestinal tract extending from the lower end of the stomach (pylorus) to the anal opening. In humans this fairly narrow (about 1 in./2.
..... Click the link for more information. at the duodenum (see digestive systemdigestive system,
in the animal kingdom, a group of organs functioning in digestion and assimilation of food and elimination of wastes. Virtually all animals have a digestive system. In the vertebrates (phylum Chordata, subphylum Vertebrata) the digestive system is very complex.
..... Click the link for more information. ). Most of the pancreatic tissue consists of grapelike clusters of cells that produce a clear fluid (pancreatic juice) that flows into the duodenum through a common duct along with bile from the liver. Pancreatic juice contains three digestive enzymes: tryptase, amylase, and lipase, that, along with intestinal enzymes, complete the digestion of proteins, carbohydrates, and fats, respectively. Scattered among the enzyme-producing cells of the pancreas are small groups of endocrine cells, called the islets of Langerhans, that secrete two hormones, insulin and glucagon. The pancreatic islets contain several types of cells: alpha-2 cells, which produce the hormone glucagon; beta cells, which manufacture the hormone insulin; and alpha-1 cells, which produce the regulatory agent somatostatin. These hormones are secreted directly into the bloodstream, and together, they regulate the level of glucose in the blood. Insulin lowers the blood sugar level and increases the amount of glycogen (stored carbohydrate) in the liver; glucagon has the opposite action. Failure of the insulin-secreting cells to function properly results in diabetesdiabetes
or diabetes mellitus
, chronic disorder of glucose (sugar) metabolism caused by inadequate production or use of insulin, a hormone produced in specialized cells (beta cells in the islets of Langerhans) in the pancreas that allows the body to use and store
..... Click the link for more information. , which can occur in two major forms, the division being between juvenile onset and onset in maturity. Pancreatic cancer has a particularly high mortality rate, and patients with a family history of the disease sometimes have the pancreas removed if precancerous cysts are present in the organ.

Pancreas

A composite gland in most vertebrates, containing both exocrine cells—which produce and secrete enzymes involved in digestion—and endocrine cells, arranged in separate islets which elaborate at least two distinct hormones, insulin and glucagon, both of which play a role in the regulation of metabolism, and particularly of carbohydrate metabolism. See Carbohydrate metabolism

Anatomy

The pancreas of mammals shows large variations. The extremes are the unique, massive pancreas of humans, and the richly branched organ of the rabbit. Usually, the main duct, the duct of Wirsung, opens into the duodenum very close to the hepatic duct. In humans, the pancreas weighs about 2.5 oz (70 g). It can be divided into head, body, and tail. Accessory pancreases are frequently found anywhere along the small intestine, in the wall of the stomach, and in Meckel's diverticulum.

The exocrine portion of the pancreas shows tubuloalveolar glands. Each terminal alveolus is called an acinus. The various acini have central cavities, which open into intralobular ducts through narrow intercalated tubes. The interlobular ducts anastomose and ultimately form the main duct of Wirsung. The activity of the acini is stimulated by secretin as well as by pilocarpine.

The endocrine portion shows cellular masses called islands or islets of Langerhans, in which the cellular cords or masses are more or less isolated by irregular spaces filled with connective tissue and blood capillaries. The two main types of cells are the alpha and the beta cells.

Between the grapelike exocrine portion with its ducts and the islands of Langerhans, it is possible to observe connective tissue septa, numerous blood vessels, and nerves.

Physiology

The pancreatic juice carried to the duodenum is a slightly alkaline liquid containing trypsinogen, which, when activated, causes the hydrolysis of the proteins into amino acids, amylase, and maltase, which act on the glucides, and lipase, which causes the hydrolysis of fatty substances. The intense stimulation of the pancreatic secretion after ingestion of food is considered to be the result of a nervous reflex originating in the mouth, and also of direct introduction of acids and fats into the duodenum, causing the liberation of a hormone called secretin into the bloodstream to stimulate the exocrine secretion.

F. Banting and C. Best (1922) prepared pancreatic extracts which were able to prevent the lethal effects of pancreatectomy. The same effect was obtained with extracts from pancreas in which, after ligature of the duct of Wirsung, the exocrine portion of the gland had disappeared.

The alpha cells and beta cells in the islets are the sources of two hormones, insulin from the beta, and glucagon, also known as the hyperglycemic factor, from the alpha. The former is a hormone which influences carbohydrate metabolism, enabling the organism to utilize sugar. The latter accelerates the conversion of liver glycogen into glucose. Glucagon elevates the blood sugar level, and its effects are the opposite of those of insulin, so that the two hormones together maintain the sugar metabolism of the body in balance. When the level of sugar in the blood becomes too low, the secretion of glucagon is stimulated. See Glucagon, Insulin

Pancreas

a large digestive gland of animals and man that has exocrine and endocrine functions and that helps digest and regulate the metabolism of carbohydrates, fats, and proteins. Among invertebrates, a separate pancreas, considered a detached part of the liver, is found only in cephalopods. In vertebrates, the pancreas is situated in the mesentery of the middle intestine, close to the stomach; in amniotes, it is in the mesentery of the duodenum. In lampreys and dipnoans, the pancreas is concealed in the intestinal wall. In hagfishes, fishes of the family Acipenseridae, and some fishes of the superorder Teleostei, the gland is found in the liver tissue, forming with the liver a single organ, the hepatopancreas.

The exocrine part of the pancreas has a complex alveolar and tubular structure. It is covered by a thin connective-tissue capsule from which bands of connective tissue branch out, separating the pancreatic parenchyma into separate lobules. Most of the lobules basically consist of terminal saclike dilatations, or acini, whose cells secrete pancreatic juice. The efferent ducts of the lobules merge into the common efferent ducts of the gland. The endocrine part of the pancreas consists of special groups of cells arranged like islets in the lobules, which are richly furnished with blood vessels and do not have excretory ducts.

In man, the pancreas is situated in the retroperitoneal space behind and beneath the stomach perpendicular to the spinal column at the level of the first and second lumbar vertebrae in the form of a flattened band stretching horizontally from the duodenum to the spleen. The gland is 15–25 cm long, 3–9 cm wide at the head, 2–3 cm thick, and weighs 70–80 g. The head of the pancreas, the thick right extremity, is situated in the curve of the duodenum, while the tail, the narrow left extremity, is close to the spleen. The body of the gland is shaped like a three-faced prism and is covered in front by a peritoneum.

The main efferent duct of the pancreas passes from the tail to the head and opens into the duodenum. The pancreas is supplied with blood through the superior and inferior pancreaticoduodenal arteries. Blood flows out into the portal vein system. The pancreas has a well-developed network of lymphatics. It is innervated by the parasympathetic and sympathetic nervous systems, the latter being presented by branches of the celiac, superior mesenteric, renal, and splenic plexus. Impulses travel from the cerebral cortex to the pancreas through the hypothalamus along parasympathetic nerve fibers to the acinar cells, islands, and smooth muscle fibers of the ducts. The sympathetic fibers proceed to the blood vessels.

Modern ideas on the physiology and functioning of the pancreas were established by I. P. Pavlov and his colleagues. In man and dogs, 1.5–2 liters and 600–800 ml of pancreatic juice, respectively, are secreted a day. The juice, a colorless and odorless fluid with an alkaline reaction, consists of inorganic (HCO^-₃, Cl^-, Na⁺, Ca²⁺, Mg²⁺) and organic (mainly proteins and enzymes) substances. Three main groups of enzymes—proteases, lipases, and amylases—help digest proteins, fats, and carbohydrates. In man and dogs the largest amount of pancreatic juice is secreted for carbohydrate digestion, the next largest amount for proteins, and the smallest amount for fats. The composition of the enzymes in the juice varies with the diet. Secretion begins one to three min after the ingestion of food and continues for six to ten hr. The rate of secretion when the stomach is empty is insignificant.

The endocrine function of the pancreas is the production of several hormones, including insulin and glucagon, which enter the bloodstream directly. The pancreas’ functions are regulated by neurohormonal mechanisms. The gland is affected by hormones of the digestive tract—secretin, pancreozymin, and gastrin—and by hormones of the thyroid and parathyroid glands, the hypophysis, and the adrenal glands. There is a close functional relationship between the pancreas and the other organs of the digestive pancreatitis. Diabetes mellitus results from disturbance of the insulin-manufacturing mechanism.

REFERENCES

Shamal’ gauzen, I. I. Osnovy sramitel’noi anatomii pozvonochnykh zhivotnykh, 4th ed. Moscow, 1947.
Pavlov, I. P. Poln. sobr. soch., 2nd ed., vol. 2, book 2. Moscow-Leningrad, 1951.
Brooks, F. P. “The Neurohumoral Control of Pancreatic Exocrine Secretion.” American Journal of Clinical Nutrition, 1973, vol. 26, no. 3. Pages 291–310.

V. B. TROITSKAIA AND T. V. SHAAK

pancreas

[′pan·krē·əs] (anatomy) A composite gland in most vertebrates that produces and secretes digestive enzymes, as well as at least two hormones, insulin and glucagon.

pancreas

a large elongated glandular organ, situated behind the stomach, that secretes insulin and pancreatic juice

Pancreas

pancreas

[pan´kre-as] (pl. pancre´ata) (Gr.) a large, elongated, racemose gland located transversely behind the stomach, between the spleen and duodenum. (See also Plate 11.) It is composed of both exocrine and endocrine tissue. The acini secrete digestive enzymes, and small ductules leading from the acini secrete sodium bicarbonate solution. The combined product, pancreatic juice, enters a long pancreatic duct and from there is transported through the hepatic duct to the duodenum. The pancreatic juice contains enzymes for the breakdown of proteins, carbohydrates, and fats. The bicarbonate ions in the pancreatic secretion help neutralize the acidic chyme that is passed along from the stomach to the duodenum.
Regulation of pancreatic secretion of enzymes and bicarbonate ions is both neural and hormonal; however, the influences of the hormones secretin and cholecystokinin are more important than vagal stimulation. The entry of chyme into the small intestine causes the transformation of an inactive proenzyme, prosecretin, into active secretin that is released from the mucosa of the upper portion of the duodenum. The composition of the partially digested food entering the duodenum influences the amount of each hormone that is released and, therefore, the characteristics of the pancreatic juice.
The endocrine functions of the pancreas are related to the islets of Langerhans located on the surface of the pancreas. These small islands contain three major types of cells: the alpha, beta, and delta cells. The alpha cells secrete the hormone glucagon, which elevates blood sugar. The beta cells secrete insulin, which affects the metabolism of carbohydrates, proteins, and fats. The delta cells secrete somatostatin, the functions of which are not fully understood, but it is known that it can inhibit the secretion of both glucagon and insulin and may act as a controller of metabolic processes. The somatostatin produced by the delta cells of the pancreas is the same as that produced by the hypothalamus as an inhibitor of the release of growth hormone from the pituitary gland.Disorders of the Pancreas. Failure of the islets of Langerhans to produce sufficient amounts of insulin results in diabetes mellitus. Disturbances in the exocrine functions of the pancreas produce serious digestive disorders. The pancreas can also be the seat of cancerous growth, and occasionally the pancreatic ducts are blocked by stones. Various factors, not yet fully understood, may result in acute pancreatitis, a condition in which the fluids digest the tissue of the organ itself. cystic fibrosis, a serious congenital disease, is characterized by a deficiency in the secretion of pancreatic juice, and an increase in its viscosity.

The anatomical relations of the pancreas. From Aspinal and Taylor-Robinson, 2001.annular pancreas a developmental anomaly in which the pancreas forms a ring entirely surrounding the duodenum.

pan·cre·as

, pl.

pan·cre·a·ta

(pan'krē-as, pan-krē-ā'tă), [TA] An elongated lobulated retroperitoneal gland, devoid of a distinct capsule, extending from the concavity of the duodenum to the spleen; it consists of a flattened head within the duodenal concavity, a neck connecting the head and body, an elongated three-sided body extending transversely across the abdomen, and a tail in contact with the spleen. The gland secretes from its exocrine part pancreatic juice that is discharged into the intestine, and from its endocrine part the internal secretions insulin and glucagon. [G. pankreas, the sweetbread, fr. pas (pan), all, + kreas, flesh]

pancreas

(păng′krē-əs, păn′-)n. A long, irregularly shaped gland in vertebrates, lying behind the stomach, that secretes pancreatic juice into the duodenum and insulin, glucagon, and somatostatin into the bloodstream.

pan′cre·at′ic (păng′krē-ăt′ĭk, păn′-) adj.

pan·cre·as

, pl. pancreata (pan'krē-ăs, -ā'tă) [TA] An elongated lobulated retroperitoneal gland extending from the duodenum to the spleen; it consists of a flattened head (caput) within the duodenal concavity, an elongated three-sided body extending transversely across the abdomen, and a tail in contact with the spleen. The gland secretes from its exocrine part pancreatic juice that is discharged into the intestine, and from its endocrine part the internal secretions, insulin and glucagon. [G. pankreas, the sweetbread, fr. pas (pan), all, + kreas, flesh]

pancreas

(pang'kre-as, pan') (pan-kre'at-a) plural.pancreata [ pan- + Gr. kreas, flesh, meat]

PANCREASA compound acinotubular gland located behind the stomach and in front of the first and second lumbar vertebrae. The head lies within the curve of the duodenum, the tail lies near the spleen, and the middle portion constitutes the body. The pancreas is both an exocrine and an endocrine organ. The exocrine glands are acini, each with its own duct; these ducts anastomose to form the main pancreatic duct or duct of Wirsung, which joins the common bile duct and empties into the duodenum at the hepatopancreatic ampulla. An accessory pancreatic duct or duct of Santorini is often present and opens into the duodenum directly. Scattered throughout the exocrine glandular tissue are masses of cells called islets of Langerhans, endocrine glands that secrete hormones. See: illustration

Function

The exocrine secretion of the pancreas consists of enzymes that digest food in the small intestine, and sodium bicarbonate to neutralize hydrochloric acid from the stomach in the duodenum. See: pancreatic juice

The islets of Langerhans contain alpha, beta, and delta cells. Alpha cells secrete glucagon, which raises blood glucose; beta cells secrete insulin, which lowers blood glucose; delta cells secrete somatostatin, which inhibits the secretion of insulin, glucagon, growth hormone from the anterior pituitary, and gastrin from the stomach.

Diseases of the Pancreas

Autoimmune damage to the islets of Langerhans results in type 1 diabetes mellitus, a disease in which insulin secretion is insufficient or completely absent. Insulin-secreting tumors of the pancreas, called insulinomas, produce hypoglycemia; they are exceptionally rare. Inflammation of the pancreas, known as pancreatitis, is a common condition that often results from excessive use of alcohol or from obstruction of the exocrine secretions of the pancreas by gallstones. Pancreas divisum is a common congenital anomaly in which the main duct of the exocrine pancreas drains into an accessory pancreatic papilla instead of the duodenal papilla; it has been associated with recurring episodes of pancreatitis. See: diabetes mellitus; insulin; pancreatic function test

accessory pancreas

A small mass of pancreatic tissue close to the pancreas but detached from it.

annular pancreas

An anomalous condition in which a portion of the pancreas encircles the duodenum.

pancreas divisum

A congenital anomaly in which the dorsal and ventral pancreatic ducts fail to unite during embryonic development. It has been associated with pancreatitis.

dorsal pancreas

A dorsal outpocketing of the embryonic gut that gives rise to the body and tail of the adult pancreas.

lesser pancreas

The semidetached lobular part of the posterior surface of a head of the pancreas, sometimes having a separate duct opening into the principal one.

ventral pancreas

An outgrowth at the angle of the hepatic diverticulum and the embryonic gut that migrates and fuses with the dorsal pancreas. It forms the head of the definitive organ.

Willis' pancreas

See: Willis, Thomas

pancreas

A dual function gland situated immediately behind the STOMACH with its head lying within the loop of the DUODENUM, into which the duct of the pancreas runs. The pancreas secretes digestive enzymes capable of breaking down carbohydrates, proteins and fats into simpler, absorbable, compounds. It is also a gland of internal secretion (an endocrine gland). The endocrine element consists of the Islets of Langerhans, specialized cells that monitor blood and produce four hormones-INSULIN, GLUCAGON, SOMATOSTATIN and a pancreatic polypeptide of unknown function. See also DIABETES.

pancreas

a gland situated in the mesentary of the DUODENUM of jawed vertebrates that has both an exocrine and an endocrine function. The pancreatic duct carries digestive enzymes (see PANCREATIC JUICES from the gland into the duodenum, secretion being stimulated by

(a) the vagus nerve,
(b) the hormone SECRETIN,
(c) PANCREOZYMIN.

Groups of cells known as ISLETS OF LANGERHANS secrete two hormones into the blood system; large ‘alpha’ cells secrete GLUCAGON, while smaller ‘beta’ cells secrete INSULIN.

Pancreas

A five-inch-long gland that lies behind the stomach and next to the duodenum. The pancreas releases glucagon, insulin and some of the enzymes which aid digestion. Pancreatitis is the swelling of the pancreas which can nausea, jaundice, and severe pain and may be fatal.Mentioned in: Adrenalectomy, Antiretroviral Drugs, Diabetes Mellitus, Diuretics, Hypotonic Duodenography, Insulin Resistance, Jaundice, Lipase Test, Pancreatectomy

Patient discussion about Pancreas

Q. Can any one give me information about Carcinoma of the pancreas? What is the prognosis for carcinoma of the pancreas? I want to know as much as I can information on carcinoma of the pancreas.A. I’m sorry to say that 95% people that have pancreatic carcinoma do not survive. Apparently the area around it and the pancreas itself is without sensory nerves. That means that when it starts to be painful – it’s much too late…this is a silent killer.
Sorry for the bad news…

Q. DO YOU KNOW HOW TO STOP YOUR PANCREAS FROM SPASMS, I HAVE A HARD TIME WHEN IT SEEMS MY PANCREAS IS ACTING UP IT HURTS SO BAD AND MY LIPIDS ARE HIGH HOW DO I GET RID OF THE PAIN OR CONTROLL IT.A. the Pancreas does not have sensory nerves in it. this is the reason why pancreas cancer is the most deadly- you don't realize it's there until it's much too late. so this pain you describe does not ad up to be from the Pancreas.
i think this is a very good reason to see a Doctor.

Q. hello friend i want to know how to over come deseases related to stomach and pancreas and what are the remedi A. you'll have to be specific. there are dozens of different diseases that affects the stomach & pancreas. and as far as i know- none of them is connected to bi-polar disorder.

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REFERENCES

pancreas

pancreas

Pancreas

pancreas

pan·cre·as

pan·cre·a·ta

pancreas

pan·cre·as

pancreas

Function

Diseases of the Pancreas

accessory pancreas

annular pancreas

pancreas divisum

dorsal pancreas

lesser pancreas

ventral pancreas

Willis' pancreas

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noun a large elongated exocrine gland located behind the stomach

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