Pancreas

What is the Pancreas?
The pancreas is a part of both the endocrine (ductless glands) and the exocrine (glands with ducts) system. It secretes the hormones that maintain the blood glucose levels.

Where is the pancreas situated?
The pancreas is obliquely placed behind the stomach and the duodenum, which is the first part of the small intestine. The pancreas stretches from the duodenum to the spleen.

How can we describe the pancreas?
The pancreas is a soft, lobulated structure. This means it is compartmentalized into small sac-like structures within the large sac. This gives it a rough, uneven appearance.

For description purposes the pancreas is divided into the head, neck, body and tail. The head lies in the concavity created by the C-shaped duodenum. There is a duct or tube arising from the pancreas that opens into the small intestine. This duct is called as the pancreatic duct and it transports the pancreatic secretions to the intestine.

Internal structure of the pancreas : The pancreas consists of clusters of cells called alpha and beta Islets of Langerhans. These islets are responsible for secretion of glucose regulating hormones. There is also presence of exocrine (with ducts) tissue which secretes digestive enzymes mainly amylase and lipase.

Functions of the Pancreas

The pancreas is mainly a digestive organ though it also secretes glucose regulating hormones. Glucose is important in the body, as it is the only form of food that can be used by the brain.

The exocrine part of the pancreas secretes amylase and lipase along with some other enzymes. These enzymes are responsible for digesting fats and starch. The pancreatic duct takes these enzymes to the intestines for digestion of food. As soon as food reaches the duodenum or the first part of the intestine, the pancreas releases the enzymes and the digestive process begins.

The endocrine part of the pancreas secretes two hormones:

The beta cells of the Islets of Langerhans secrete insulin while the alpha cells secrete glucagon.
• Insulin: It lowers the blood glucose levels if they exceed a certain limit. Usually the normal fasting level of glucose is 120mg% and that after meals is 180mg%. If the levels exceed these limits, the hormone insulin stimulates the body cells to absorb more glucose. It also stimulates the liver to form glycogen from glucose, which can then be stored in the liver. It also promotes the formation of fatty acids from glucose. Thus insulin causes increased utilization of glucose by the body. Lack of insulin causes diabetes mellitus.
• Glucagon: This hormone increases the blood glucose levels by stimulating the breakdown of glycogen and similarly stored glucose in the liver and muscle.