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.
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.
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.
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.
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.
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.