They are relatively difficult to distinguish using standard staining techniques, but they can be classified by their secretion. The islets are a compact collection of endocrine cells arranged in clusters and cords and are crisscrossed by a dense network of capillaries.
The capillaries of the islets are lined by layers of endocrine cells in direct contact with vessels, and most endocrine cells are in direct contact with blood vessels, either by cytoplasmic processes or by direct apposition.
Pancreatic fluid contains digestive enzymes that help to further break down the carbohydrates, proteins, and lipids in the chyme.
It is both an endocrine gland that produces several important hormones—including insulin, glucagon, somatostatin, and pancreatic polypeptide—and a digestive organ that secretes pancreatic juice that has digestive enzymes that assist the absorption of nutrients and digestion in the small intestine.
Pancreatic juice is a liquid secreted by the pancreas that contains a variety of enzymes, including trypsinogen, chymotrypsinogen, elastase, carboxypeptidase, pancreatic lipase, nucleases, and amylase. Pancreatic fluid : A schematic diagram that shows pancreatic acini and the ducts where fluid is created and released. Pancreatic juice is alkaline in nature due to its high concentration of bicarbonate ions that neutralize the gastric acid and allow effective enzymic action.
Pancreatic juice secretion is regulated by the hormones secretin and cholecystokinin. It is produced by the walls of the duodenum upon detection of acid food, proteins, fats, and vitamins. Pancreatic secretion consists of an aqueous bicarbonate component from the duct cells and an enzymatic component from the acinar cells.
Because the pancreas is a sort of storage depot for digestive enzymes, injury to the pancreas is potentially fatal. A puncture of the pancreas generally requires prompt and experienced medical intervention.
A variety of factors cause a high pressure within pancreatic ducts. Pancreatic duct rupture and pancreatic juice leakage cause pancreatic self-digestion. Privacy Policy. Skip to main content. Digestive System. Search for:. The Pancreas. Pancreas The pancreas is a gland organ in the digestive and endocrine systems. Learning Objectives Describe the function of the pancreas. Key Takeaways Key Points The pancreas is a gland organ in the digestive and endocrine systems.
Key Terms pancreas : A gland near the stomach that secretes a fluid into the duodenum to help with food digestion. Anatomy of the Pancreas The pancreas lies in the epigastrium or upper central region of the abdomen and can vary in shape. Learning Objectives Outline the anatomy of the pancreas.
Key Takeaways Key Points The pancreas lies in the epigastrium or upper central region of the abdomen. The pancreas is composed of a head, uncinate process, neck, body, and tail. A number of blood vessels connect the pancreas to the duodenum, spleen, and liver. Key Terms epigastrium : The upper middle region of the abdomen, between the umbilical and hypochondriac regions.
A duct runs the length of the pancreas, and it is joined by several small branches from the glandular tissue. The end of this duct is connected to a similar duct that comes from the liver, which delivers bile to the duodenum.
Around 95 percent of the pancreas is exocrine tissue. It produces pancreatic enzymes to aid digestion. A healthy pancreas makes about 2. The remaining 5 percent comprises hundreds of thousands of endocrine cells known as islets of Langerhans. These grape-like cell clusters produce important hormones that regulate pancreatic secretions and control blood sugar.
The exocrine tissues secrete a clear, watery, alkaline juice that contains several enzymes. These break down food into small molecules that can be absorbed by the intestines. If the pancreas does not produce enough digestive enzymes, for example, food will not be properly absorbed. This can lead to weight loss and diarrhea. The islets of Langerhans are responsible for regulating blood glucose. Too little insulin production will increase the risk of diabetes, and blood glucose levels will rise.
Pancreatitis refers to an acute or chronic inflammation of the pancreas. It can lead to secondary diabetes. Inflammation can occur if the main duct from the pancreas is blocked by a gallstone or tumor. Pancreatic juices will accumulate in the pancreas, causing damage to the pancreas.
The pancreas may start to digest itself. Pancreatitis can happen as a result of mumps, gallstones, trauma and the use of alcohol, steroids, and drugs. Immediate treatment is normally with fluids and painkillers. Patients often do not want to eat at the beginning, but if the pancreatitis is mild, they will start to eat again relatively quickly.
Chronic pancreatitis can develop if acute pancreatitis happens repeatedly, resulting in permanent damage. Hereditary pancreatitis can happen if there is an inherited problem in the pancreas or the intestine. A person under 30 years of age may experience repeated acute pancreatitis, leading to a chronic condition. It is a progressive condition that can lead to permanent damage.
The person may experience pain, diarrhea, malnutrition or diabetes. Treatment aims to control pain to replace lost enzymes. The most important hormone that the pancreas produces is insulin. Insulin is released by the 'beta cells' in the islets of Langerhans in response to food.
Its role is to lower glucose levels in the bloodstream and promote the storage of glucose in fat, muscle, liver and other body tissues. This has the opposite effect to insulin, by helping release energy into the bloodstream from where it is stored, thus raising blood sugar levels.
Therefore, glucagon and insulin work in tandem to control the balance of glucose in the bloodstream. Other hormones produced by the pancreas include pancreatic polypeptide and somatostatin.
They are believed to play a part in regulating and fine-tuning the insulin and glucagon-producing cells. Type 1 diabetes mellitus is caused when the body's immune system attacks its own cells in the islets of Langerhans, meaning that these cells cannot produce insulin. Type 2 diabetes mellitus is a metabolic disorder where the body is no longer able to produce or respond to insulin. Some women also get diabetes temporarily when they are pregnant.
This is called gestational diabetes. There are other rarer forms of diabetes, some of which are inherited. In addition, people will get diabetes if their pancreas is taken away surgically or damaged for instance by severe pancreatitis. Very rarely, patients develop growths tumours of the cells that make up the islets of Langerhans.
These may be benign tumours, where a particular kind of cell multiplies and makes large quantities of its hormone whether it is needed or not. For example, if the tumour is made of insulin-producing cells, it is called an insulinoma. This is where too much insulin is produced when it is not required.
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