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The Pancreas

Home
Table of Contents
Introduction
The Lungs
The Trachea
The Testes
The Submaxillary Gland
The Liver
The Stomach and Duodenum
The Blood
The Arteries and Veins
The Adipose Tissue
The Skin
The Pituitary Gland
The Pancreas
The Thyroid
The Kidney
The Spinal Cord
The Cerebellum
The Elastic Cartilage
The Bone
The Smooth Muscle
The Striated Muscle
Conclusion
Bibliography

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The pancreas is long, triangular glandular organ located underneath the stomach in the abdominal cavity. It serves a dual purpose as a gland that secretes both digestive enzymes which aid in breaking down food, and as a gland that secretes insulin and glucagon, which glucose levels in the bloodstream.

 

 As a digestive organ, the pancreas releases pancreatic amylase when partially digested foods enter the small intestine. Pancreatic amylase acts on carbohydrates, breaking down polysaccharides into disaccharides. The pancreas also releases the inactive form of three enzymes; trypsin, chymotrypsin, and carboxypeptidase. Once the inactive forms of these enzymes move down the pancreatic duct into the small intestine, they are activated by intestinal enzymes that are released in the presence of food. These enzymes then work to break down short polypeptide chains into shorter chains, and finally amino acids, along with other peptidases found in the intestine.

 

As a part of the endocrine system, the pancreas works to control the amount of glucose found in the blood and tissues.

 

The endocrine hormones of the pancreas are produced and secreted by parts of the pancreas called the islets of Langerhans. The islets of Langerhans contain three types of cells; Alpha cells which secrete glucagon, Beta cells which secrete insulin, and Delta cells which secrete Somatostatin, which influences insulin and glucagon levels.

 

When the glucose levels in the bloodstream are elevated, for example after a meal, the beta cells in the pancreatic islets release insulin. Insulin causes the tissues to become more permeable to glucose, absorbing it from the blood. It also causes extra glucose that can not be absorbed by the tissues to be converted and stored by the liver as glycogen.

 

When blood glucose levels are low, for example when meals are skipped, the alpha cells of the pancreatic islets release glucagon, which acts directly on the liver. Glucagon causes the liver to convert its glycogen stores back into glucose, which is then released into the blood, restoring blood sugar levels to normal.

 

In some cases, the pancreas can not produce sufficient insulin, or the insulin it does produce is not sufficient to control blood sugar levels. This condition is known as diabetes, and comes in three forms. The first, Type I diabetes, is congenital, occurs in young people, and is caused by beta cells which have been destroyed, or do not produce insulin. Type II diabetes, occurring in older people, is caused by poor eating habits or obesity, where insulin levels are abnormally high to the point that insulin receptors in the cells are destroyed. This makes it harder for insulin to act on the tissues and make them more permeable to glucose, so in effect, the insulin can not do its job. The third type of diabetes, gestational diabetes, and is caused by hormonal interference in both mother and child during pregnancy.

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THE WONDERS OF THE HUMAN BODY!