Posted in Psychology & Medicine

Viscera: Pancreas

(Learn more about the organs of the human bodies in other posts in the Viscera series here:

The pancreas is probably the most central organ in the human body. It is situated just under the liver and stomach, surrounded by the duodenum (first part of small intestine) and lies in front of the aorta. It is shaped like a fish and thus is divided into parts named the head, neck, body and tail. The head of the pancreas tucks into the loop of duodenum and drains its contents via the pancreatic duct, which joins with the common bile duct (from the liver and gallbladder).


The function of the pancreas is divided into two functions: exocrine and endocrine.

An exocrine gland is an organ that excretes its products out of the body (including the intestines), such as the salivary or tear glands. The exocrine function of the pancreas is the production and secretion of digestive enzymes that break down proteins, fats and carbohydrates in the small intestine. Because of this, injury to the pancreas often causes a leak of this digestive juice, causing the body to self-digest the pancreas (leading to pancreatitis) and surrounding organs.

An endocrine gland is the opposite in that it secretes its contents into the bloodstream. These glands typically produce hormones, such as the thyroid, ovaries and adrenal glands. The pancreas’ endocrine function is related to an extremely common yet deadly disease: diabetes. Within the pancreas, there are millions of cells that cluster into groups called islets of Langerhans. There are various types of cells, but the most common are the alpha-islet cells that secrete glucagon and beta-islet cells that secrete insulin. Insulin acts to lower blood sugar (glucose) levels by promoting storage and use of glucose after a meal. Glucagon acts to increase blood glucose by promoting the breakdown of glucose storage units (glycogen) and the production of more glucose by the liver. Diabetes occurs when beta-islet cells fail to produce insulin because they are destroyed by the immune system (type 1 diabetes mellitus) or become desensitised by chronically elevated blood glucose levels (type 2 diabetes mellitus).

Another important disease concerning the pancreas is pancreatic cancer. Pancreatic cancer is notorious for its deadliness as it carries a 5-year mortality rate of over 95%. This is because it usually remains hidden – without any symptoms – until it as grown substantially and spread to other organs. However, this prognosis only applies to the most common type of pancreatic cancer involving exocrine cells (adenocarcinoma). There are far rarer cancers of the pancreas that involve the endocrine cells (e.g. insulinoma), which tend to have extremely good prognoses and are usually curable.

Steve Jobs (founder of Apple Inc.) had this kind of pancreatic cancer – an islet cell neuroendocrine tumour. Despite his excellent chance of cure with chemotherapy and surgery, he refused treatment for nine months and instead relied on alternative medicine for cure. However, his disease worsened and he finally resorted to having surgery. By this stage, his disease had spread to the liver due to the nine-month delay in treatment. Spreading of cancer is called metastasis and is often an indication that the cancer is no longer curable. Jobs went against his doctors’ advice and opted for a liver transplant in the hopes of curing his cancer. Organ transplant involves suppressing the patient’s immune system (which also keeps cancers in check) to prevent rejection of the donor organ, which is why oncologists advise against transplants in cancer patients. Jobs’ condition deteriorated quickly after his liver transplant and his decisions ultimately led to his demise.