Many years ago, one of America’s most accomplished medical writers, Dr. Lewis Thomas, described how insecure he would be if faced with taking on the responsibilities of his liver. He wrote that he was considerably less intelligent and unable to make all of the decisions the liver is designed for.  

Thomas would have been even more humble had he chosen the pancreas. When it functions properly, this organ is silent and unrecognized, but when it malfunctions, extraordinary complications and even death can ensue. Even in the 21st century, when medical discoveries abound, the pancreas carries an aura of mystery and its diseases present a challenge for diagnosis and treatment. Fortunately, research is ongoing and progress is being made to treat pancreatic diseases.

The pancreas was first described by the Greek anatomist and surgeon Herophilus in approximately 310 BC. Herophilus (335 B.C. to 280 B.C.) may have been one of the first surgeons to dissect the human body using criminals from prison. He was given royal permission to procure them, even though there was public criticism of the practice. The reason may have been that some of his dissections were performed while the criminals were still alive.

Herophilus, however, did not name the pancreas. The term may first have been used by Aristotle (384–322 B.C.) in his treatise Histora Animalium, although there was some controversy regarding his description.

It was not until the latter half of the 15th century that the first signs of advancements in medicine became apparent. Giacomo Berengario da Carpi (1470–1550), a professor of surgery in Bologna, Italy, produced the first illustrated textbook of anatomy. He accurately described the bile duct and wrote of the pancreas as a secretory gland.

His work was followed by one of true genius several years later.

In 1543, Andreas Vesalius (1515–1564) published his famous textbook of anatomy, De Humani corporis fabrica libri VII (“Seven books on the workings of the human body”). With its publication, medicine was finally lifted out of medieval murkiness and misinformation. The book, an outgrowth of the vigorous spirit of the Renaissance, corrected a number of ancient Roman physician Galen’s errors and returned society to the logical thought and observational methods of the ancient Greeks.

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 6 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.

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.

Scattered throughout the exocrine tissue are small, isolated pockets of endocrine tissue; these pockets are known as the islets of Langerhans. The islets are composed of several types of cells that produce insulin and glucagon. 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 mechanisms come with a terrible downside that helps explain why pancreatic cancer can be so difficult to treat.

Pancreatic cancer is one of the deadliest of all solid malignancies. The five-year survival rate is only 4 percent. 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.

Cigarette smoking is by far the leading preventable cause of pancreatic cancer; it doubles the risk. It is believed that as many as 1 in 4 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 mellitus, chronic pancreatitis and a family history of the disease.

The pancreas is also the linchpin in two current epidemics. When the pancreas goes awry it is the source of diabetes, which afflicts more than 23 million people in the US. And as the tireless brewer of digestive juices, the pancreas is at the front line of the growing incidence of obesity that affects 60 percent of Americans.

Researchers have found that the pancreas helps mediate appetite-related messages between the brain and the gastrointestinal tract. However, it is not quite clear how the pancreas conveys sensations of hunger and satiety. When these are understood, the knowledge could lead to new ways to combat obesity.

Max Sherman is a medical writer and pharmacist retired from the medical device industry. He has taught college courses on regulatory and compliance issues at Ivy Tech, Grace College and Butler University. Sherman has an unquenchable thirst for knowledge on all levels. Eclectic Science, the title of his column, will touch on famed doctors and scientists, human senses, aging, various diseases, and little-known facts about many species, including their contributions to scientific research. He can be reached by email at