The pancreas (अग्न्याशय) is an organ of the digestive system and endocrine system of vertebrates. In humans, it is located in the abdomen behind the stomach and functions as a gland. As a part of the digestive system, it functions as an exocrine gland secreting pancreatic juice into the duodenum through the pancreatic duct. To know pancreas, structure, development, and clinical significance, Siddha Spirituality of Swami Hardas Life System appeals to our valuable readers to definitely read this article as it would be of great help to people affected with diabetes mellitus.
Pancreas Definition (अग्न्याशय की परिभाषा)
A spongy, tube-shaped organ that is about 6 inches long and is located in the back of the abdomen, behind the stomach. The head of the pancreas is on the right side of the abdomen. The narrow end of the pancreas, called the tail, extends to the left side of the body, however, the pancreas makes pancreatic juices and hormones, including insulin and secretin. But, the exocrine function of the pancreas involves the synthesis and secretion of pancreatic juices.
Pancreas Structure (अग्न्याशय की संरचना)
The pancreas is an organ that in humans lies in the upper left part of the abdomen. In adults, it is about 12–15 centimeters (4.7–5.9 in) long, lobulated, and salmon-colored in appearance.
Anatomically, the pancreas is divided into a head, neck, body, and tail.
The head of the pancreas sits within the curvature of the duodenum and wraps around the superior mesenteric artery and vein. To the right sits the descending part of the duodenum and between these travel the superior and inferior pancreaticoduodenal arteries. Behind rests the inferior vena cava, and in front sits the peritoneal membrane and the transverse colon.
Body and neck (शरीर और गर्दन)
The body of the pancreas travels from the head, separated by a short neck. The neck is about 2 cm (0.79 in) wide and sits in front of the portal vein. The gastroduodenal artery and the anterior superior pancreaticoduodenal arteries travel in front of the gland and begin where the neck meets the head of the pancreas. The neck lies mostly behind the pylorus of the stomach.
The pancreas narrows towards the tail, which sits next to the spleen. It is usually between 1.3–3.5 cm (0.51–1.38 in) long, and sits between the layers of the ligament between the spleen and the left kidney. The splenic vein, which also passes behind the body of the pancreas, passes behind the tail of the pancreas.
Blood supply (रक्त की आपूर्ति)
The pancreas has a rich blood supply, with vessels originating as branches of both the coeliac artery and superior mesenteric artery. However, splenic artery runs along the top margin of the pancreas and supplies the left part of the body and the tail of the pancreas through its pancreatic branches.
Both, superior and inferior pancreaticoduodenal arteries run along the anterior and posterior surfaces of the head of the pancreas at its border with the duodenum. These supply the head of the pancreas. These vessels join together in the middle.
Microanatomy (सूक्ष्म शरीर रचना विज्ञान)
The pancreas contains tissue with an endocrine and exocrine role, and this division is also visible when the pancreas is viewed under a microscope.
Pancreatic islets contain alpha cells, beta cells, delta cells, and PP cells, each of which releases a different hormone.
The size of the pancreas varies considerably. Several anatomical variations exist, relating to the embryological development of the two pancreatic buds. The pancreas develops from these buds on either side of the duodenum. The ventral bud eventually rotates to lie next to the dorsal bud, eventually fusing. If the two buds, each having a duct, do not fuse, a pancreas may exist with two separate ducts, a condition known as a pancreas divisum.
Gene and protein expression (जीन और प्रोटीन अभिव्यक्ति)
Similar to the salivary glands, most of the pancreas-specific genes encode for secreted proteins.
Corresponding pancreas-specific proteins are either expressed in the exocrine cellular compartment and have functions related to digestion of food uptakes such as digestive chymotrypsinogen enzymes and pancreatic lipase PNLIP, or expressed in the various cells of the endocrine pancreatic islets and have functions related to secreted hormones such as insulin, glucagon, somatostatin, and pancreatic polypeptide.
Pancreas Development (अग्न्याशय का विकास)
As part of embryonic development, the pancreas forms as two buds from the foregut, an embryonic tube that is a precursor to the gastrointestinal tract. It is therefore of endodermal origin. Pancreatic development begins with the formation of a dorsal and ventral pancreatic bud.
The definitive pancreas results from rotation of the ventral bud and the fusion of the two buds. The rotation of the ventral bud occurs in tandem with the duodenum, which also rotates to the right. Upon reaching its final destination, the ventral pancreatic bud fuses with the much larger dorsal pancreatic bud.
Insulin and glucagon can be detected in the human fetal circulation by the fourth or fifth month of fetal development.
Pancreas Function (अग्न्याशय का कार्य)
The pancreas is involved in blood sugar control and metabolism within the body, and also in the secretion of substances (collectively pancreatic juice) which help digestion. These are divided into an “endocrine” role, relating to the secretion of insulin and other substances within pancreatic islets and helping control blood sugar levels and metabolism within the body, and an “exocrine” role, relating to the secretion of enzymes involved in digesting substances from outside of the body.
Blood glucose regulation (रक्त शर्करा विनियमन)
Cells within the pancreas help to maintain blood sugar levels (homeostasis). The cells that do this are located within the pancreatic islets that are present throughout the pancreas. When blood glucose levels are low, alpha cells secrete glucagon, which increases blood glucose levels. When blood glucose levels are high, beta cells secrete insulin to decrease glucose in the blood. Delta cells in the islet also secrete somatostatin which decreases the release of insulin and glucose.
The pancreas plays a vital role in the digestive system. It does this by secreting a fluid that contains digestive enzymes into the duodenum, the first part of the small intestine that receives food from the stomach. These enzymes help to break down carbohydrates, proteins, and lipids (fats). The cells that do this are arranged in clusters called acini. Secretions into the middle of the acinus accumulate in intralobular ducts, which drain to the main pancreatic duct, which drains directly into the duodenum.
Additional functions of Pancreas (अग्न्याशय के अतिरिक्त कार्य)
The pancreas also secretes VIP and pancreatic polypeptide. Enterochromaffin cells secrete the hormones motilin, serotonin, and substance P.
Pancreas Clinical significance (अग्न्याशय का नैदानिक महत्व)
Acute pancreatitis (तीव्र अग्नाशयशोथ)
Acute pancreatitis is likely to cause intense pain in the central abdomen, which often radiates to the back, and maybe associated with nausea or vomiting. Severe pancreatitis may lead to bleeding or perforation of the pancreas resulting in shock or a systemic inflammatory response syndrome, bruising of the flanks or the region around the belly button.
In pancreatitis, enzymes of the exocrine pancreas damage the structure and tissue. Detection of some of these enzymes with Ultrasound or a CT scan often indicates that a person has pancreatitis.
Chronic pancreatitis (पुरानी अग्नाशयशोथ)
Chronic pancreatitis refers to the development of pancreatitis over time. It shares many similar causes, with the most common being chronic alcohol use, with other causes including recurrent acute episodes and cystic fibrosis.
Digestive system (पाचन तंत्र)
Abdominal pain, characteristically relieved by sitting forward or drinking alcohol, is the most common symptom. The digestive function of the pancreas when severely affected, which may lead to problems with fat digestion and the development of steatorrhoea. However, when the endocrine function is affected, this may lead to diabetes.
Pancreatic cancers, particularly the most common type, pancreatic adenocarcinoma, remain very difficult to treat and are mostly diagnosed only at a stage that is too late for surgery, which is the only curative treatment. Pancreatic cancer is rare in those younger than 40, and the median age of diagnosis is 71.
Risk factors (जोखिम)
Risk factors include:
- Chronic pancreatitis
- Older age
- Diabetes mellitus
- Certain rare genetic conditions including multiple endocrine neoplasia type 1
- Hereditary nonpolyposis colon cancer
- Dysplastic nevus syndrome among others
Pancreatic adenocarcinoma is the most common form of pancreatic cancer and is cancer arising from the exocrine digestive part of the pancreas. Most occur in the head of the pancreas. Symptoms tend to arise late in the course of cancer when it causes abdominal pain, weight loss, or yellowing of the skin i.e. jaundice.
A solid pseudopapillary tumor is a low-grade malignant tumor that typically afflicts young women.
Diabetes mellitus (मधुमेह)
Type 1 diabetes (मधुमेह प्रकार 1)
Diabetes mellitus type 1 is a chronic autoimmune disorder in which the immune system attacks the insulin-secreting cells of the pancreas. Insulin is needed to keep blood sugar levels within optimal ranges, and its lack can lead to high blood sugar. As an untreated chronic condition, diabetic neuropathy can result.
In addition, if there is not enough insulin for glucose to be used within cells, the medical emergency diabetic ketoacidosis, which is often the first symptom that a person with type 1 diabetes may have, can result. Type 1 diabetes can develop at any age but is most often diagnosed before adulthood. For people living with type 1 diabetes, insulin injections are critical for survival.
An experimental procedure to treat type 1 diabetes is the transplantation of pancreatic islet cells from a donor into the patient’s liver so that the cells can produce the deficient insulin.
Type 2 diabetes (मधुमेह प्रकार 2)
Diabetes mellitus type 2 is the most common form of diabetes. The causes for high blood sugar in this form of diabetes usually are a combination of insulin resistance and impaired insulin secretion, with both genetic and environmental factors playing an important role in the development of the disease.
The management of type 2 diabetes relies on a series of changes in diet and physical activity with the purpose of reducing blood sugar levels to normal ranges and increasing insulin sensitivity. Biguanides such as metformin are also used as part of the treatment along with insulin therapy.
It is possible for one to live without a pancreas, provided that the person takes insulin for the proper regulation of blood glucose concentration and pancreatic enzyme supplements to aid digestion.