Pancreas


 Pancreas


Pancreas- Pancreas is a soft, pink, brown, flat and about 12 to 15 cm (5 to 6 inches) long gland which is situated behind the stomach transversely with the support of abdominal wall. It is lie from duodenum to spleen.

It has three parts-Pancreatic tissue is made up of both types of cells- exocrine and endocrine. Exocrine cells make the group of cells, called acini.

  1. Head- It is the widest part of the pancreas and situated in concavity of ‘C’-shape of duodenum rightwards in abdominal cavity.
  2. Body- It is the important part of the pancreas and situated behind the stomach in front of second and third lumber vertebra.
  3. Tail- It is a narrow and pointed part going towards the left side of pancreas and situated in front of left kidney and up to spleen.

Microscopic anatomy- Pancreatic tissue is made up of both types of cells- exocrine and endocrine. Exocrine cells make the group of cells, called acini. It appears like the bunches of grapes and secretes digestive enzymes in small intestine. Pancreas produces about 1.5 liter digestive juices daily.

       Group of special endocrine cells are found in between acini that form a net like structure and having many cells. These cells are known as islets of langerhans. These islets secrete hormones named insulin that reaches directly in blood. So, the pancreas acts like both digestion and endocrine.

        Exocrine cells (Acinus’s) are found in bunches around tiny vessels passing from tail to head in pancreas. Every acinus’s has a central lumen that connects with main pancreatic duct or duct of wirsung. It carries digestive enzymes towards ascending part of duodenum. Accessory pancreatic duct or duct of santorini secretes little amount of pancreatic enzymes in the duodenum about one inch above the main duct. Main pancreatic duct does not pour its enternal things directly in the duodenum, but connects with common bile duct, called hepatopancratic ampulla or ampulla or vater. 

        Exocrine cells (Acinus’s) produces and secretes a transparent alkaline fluid, called pancreatic juice. It has water and salt as well as three types of enzymes which do final digestion of proteins, carbohydrates and lipid.-

Lipase- It converts triglycerides into glycerol and free fatty acids after breaking in small particles resulting it is being absorbed easily. 

Amylase- It converts polysaccharides (starch) into monosaccharide and disaccharides especially into maltose on which there is not affect of the amylase of saliva falls. Due to action of maltase enzymes on maltose, it is converted into glucose. 

Trypsinogen- It is found as inactive form in pancreatic juice. After reaching in duodenum, it is converted into active trypsin by the action of enzymes called enterokinase secreted by small intestine. Trypsin, in its active form, converts peptones and proteins into amino acids, which is absorbed by blood.

Secretion of pancreatic juice- When taste buds present inside the mouth comes in contact of food particles, it sends impulses to brain that stimulates pancreas through Vegas nerves. When partial digested cymae reaches in the duodenum from stomach, it increases pancreatic function through two hormones named secretin and cholecystokinin, resulting secretion of pancreatic juice is increased. The secretion of pancreatic juice takes place only at the time of digestion.