103
the organ, but also definitively established the role of the pancreas as a secretory gland.9
This discovery abolished the previous theory that the pancreas acted as a cushion of
the stomach and led directly to studies of the physiology of the gastrointestinal tract by
Claude Bernard (1812–78). Bernard’s work, published in 1856, was briefly entitled Memoire
sur le pancreas et sur le role du suc pancreatique dans la digestion des matieres grasses neuters
(“Memoir on the pancreas and the role of pancreatic juice in the digestion of neutral fat
substances”). It was the classic document of pancreatic physiology. When Claude Bernard
died in Paris at the age of 65, he was the first French scientist to be given a state funeral.
Anatomy and Function
The pancreas is located partially behind the stomach and attached to the duodenum
(a portion of the small intestine connected to the stomach). The human pancreas is a
large gland that weighs about 70 grams. It is about six inches long, and its inverted,
bowl-shaped head and elongated body make it look like a salmon-colored snake lying
transversely across the back of the upper abdomen.10 The pancreas is composed of two
main elements: exocrine tissue and endocrine tissue. Exocrine tissue makes up the bulk of
the pancreas. It is organized into a large number of saclike structures whose interiors are
lined with cells that secrete various enzymes important to the digestive process. As these
pancreatic juices are made, they flow into the main pancreatic duct. This duct joins the
common bile duct, which connects the pancreas to the liver and gall bladder.11
Scattered throughout the exocrine tissue are small, isolated pockets of endocrine tis-
sue these pockets are known as the islets of Langerhans. The islets may be composed of
several types of cells, but the predominant constituents are alpha and beta cells. Granules
in the beta cells produce insulin, while those in the alpha cells produce glucagon.12 Both
hormones are secreted directly into the bloodstream. Insulin helps control carbohydrate
metabolism, while glucagon counters the action of insulin.
Researchers today remain intrigued by the mysterious means by which the pancreas
shields itself from harm. It can churn out huge quantities of enzymes to rapidly reduce
our fast food diets into particles of amino acids, carbohydrates and fats without digesting
its own tissue in the process. Researchers suspect that the organ’s self-protective mecha-
nisms come with a terrible downside that helps explain why pancreatic cancer can be so
difficult to treat.13
Pancreatic Cancer
The past two decades have witnessed an explosion in our understanding of pancreatic
cancer. It is now clear that pancreatic cancer is a disease of inherited (germ-line from egg
or sperm) and somatic (cells of the body) gene mutations.14 Unfortunately, because of the
pancreas’ deep location, pancreatic tumors are rarely palpable, which explains why many
symptoms of pancreatic cancer often do not appear until the tumor grows large enough
to interfere with the function of nearby structures such as the stomach, duodenum, liver
or gall bladder. Although the actual cell of origin for pancreatic cancer remains elusive,
minor populations of cells with stem-like properties appear responsible for tumor initia-
tion and metastasis and the resistance of pancreatic cancer to conventional therapies.
Pancreatic cancer is one of the deadliest of all solid malignancies. The five-year sur-
vival rate is only 4%.15 More than 35,000 Americans were diagnosed with pancreatic cancer
in 2007, making the disease the fourth leading cause of cancer deaths. Pancreatic cancer is
rare before age 40 the median age at diagnosis is 73.16 Cigarette smoking is by far the lead-
ing preventable cause of pancreatic cancer it doubles the risk. It is believed that as many
as one in four cases may be attributable to smoking. Other established risk factors include
a diet high in meats and fat, low serum folate levels, obesity, longstanding diabetes mel-
litus, chronic pancreatitis and a family history of the disease.17
The Pancreas—Mysteries of a Hidden Organ
the organ, but also definitively established the role of the pancreas as a secretory gland.9
This discovery abolished the previous theory that the pancreas acted as a cushion of
the stomach and led directly to studies of the physiology of the gastrointestinal tract by
Claude Bernard (1812–78). Bernard’s work, published in 1856, was briefly entitled Memoire
sur le pancreas et sur le role du suc pancreatique dans la digestion des matieres grasses neuters
(“Memoir on the pancreas and the role of pancreatic juice in the digestion of neutral fat
substances”). It was the classic document of pancreatic physiology. When Claude Bernard
died in Paris at the age of 65, he was the first French scientist to be given a state funeral.
Anatomy and Function
The pancreas is located partially behind the stomach and attached to the duodenum
(a portion of the small intestine connected to the stomach). The human pancreas is a
large gland that weighs about 70 grams. It is about six inches long, and its inverted,
bowl-shaped head and elongated body make it look like a salmon-colored snake lying
transversely across the back of the upper abdomen.10 The pancreas is composed of two
main elements: exocrine tissue and endocrine tissue. Exocrine tissue makes up the bulk of
the pancreas. It is organized into a large number of saclike structures whose interiors are
lined with cells that secrete various enzymes important to the digestive process. As these
pancreatic juices are made, they flow into the main pancreatic duct. This duct joins the
common bile duct, which connects the pancreas to the liver and gall bladder.11
Scattered throughout the exocrine tissue are small, isolated pockets of endocrine tis-
sue these pockets are known as the islets of Langerhans. The islets may be composed of
several types of cells, but the predominant constituents are alpha and beta cells. Granules
in the beta cells produce insulin, while those in the alpha cells produce glucagon.12 Both
hormones are secreted directly into the bloodstream. Insulin helps control carbohydrate
metabolism, while glucagon counters the action of insulin.
Researchers today remain intrigued by the mysterious means by which the pancreas
shields itself from harm. It can churn out huge quantities of enzymes to rapidly reduce
our fast food diets into particles of amino acids, carbohydrates and fats without digesting
its own tissue in the process. Researchers suspect that the organ’s self-protective mecha-
nisms come with a terrible downside that helps explain why pancreatic cancer can be so
difficult to treat.13
Pancreatic Cancer
The past two decades have witnessed an explosion in our understanding of pancreatic
cancer. It is now clear that pancreatic cancer is a disease of inherited (germ-line from egg
or sperm) and somatic (cells of the body) gene mutations.14 Unfortunately, because of the
pancreas’ deep location, pancreatic tumors are rarely palpable, which explains why many
symptoms of pancreatic cancer often do not appear until the tumor grows large enough
to interfere with the function of nearby structures such as the stomach, duodenum, liver
or gall bladder. Although the actual cell of origin for pancreatic cancer remains elusive,
minor populations of cells with stem-like properties appear responsible for tumor initia-
tion and metastasis and the resistance of pancreatic cancer to conventional therapies.
Pancreatic cancer is one of the deadliest of all solid malignancies. The five-year sur-
vival rate is only 4%.15 More than 35,000 Americans were diagnosed with pancreatic cancer
in 2007, making the disease the fourth leading cause of cancer deaths. Pancreatic cancer is
rare before age 40 the median age at diagnosis is 73.16 Cigarette smoking is by far the lead-
ing preventable cause of pancreatic cancer it doubles the risk. It is believed that as many
as one in four cases may be attributable to smoking. Other established risk factors include
a diet high in meats and fat, low serum folate levels, obesity, longstanding diabetes mel-
litus, chronic pancreatitis and a family history of the disease.17
The Pancreas—Mysteries of a Hidden Organ