Over the last two years I have encountered a fair number of SI practitioners who do not know where the pancreas is located. This leads me to suspect that there are probably a fair number who also do not understand the functions of the pancreas. The pancreas is very vulnerable to injury with abdominal work and the consequences can alter many important physiologic functions. Therefore, I have decided to write an article on the pancreas.

My intention with this article is to give an overview of the functions, embryology and location of the pancreas and explain why that knowledge is important to SI abdominal work. I will admit I am an inveterate physiology geek. I find bony and muscular anatomy a pale dull second to the study of physiology. When I was a nursing student, I would enjoy spending my spare time in the school library with physiology texts by Best and Taylor or Guyton reading things like what happens to make me say, ?I?m thirsty.? As a result of that passion, I had to do a number of revisions to this discussion to avoid producing an article that was far too long. If you find this discussion interesting, I encourage you to follow up with your own more detailed pursuit in a good physiology textbook.(1)

Before I launch into the physiology of the pancreas, let me point out that the entire physiology of the body is accomplished by feedback loops. These feedback loops are intricate, amazing, and are the mechanisms by which the body maintains balance and homeostasis in its functions. The physiology of the body is a perfect example of how everything is in relationship and nothing is isolated.

<center>Functions of the Pancreas</center>

The pancreas has two different functions. It has an exocrine (ducted) digestive function through production of enzymes. The other is an endocrine (ductless) hormonal function through the production of insulin and glucagon. I will discuss those functions separately.

<center>Pancreatic Digestive Function</center>

After food in the stomach is mixed with stomach secretions, that mix is called chime which is like a murky paste. Chyme is highly acidic, the state needed for proper breakdown of food which will allow all of its nutrient components to be absorbed by the tissues through the cells. There are specialized cells lining the esophagus and stomach that produce large amounts of mucus to protect these tissues from destruction by the highly acid liquids in the stomach. When chyme begins to leave the stomach and enter the intestine in the duodenum, feedback loops are triggered in the pancreas.

The pancreas has specialized cells called Ancini cells. These cells secrete enzymes that assist with the digestion of proteins, carbohydrates and fats. The pancreas secretes large amounts of bicarbonate ions that help neutralize the acidity of the chyme emptied from the stomach into the duodenum. This not only protects the intestine but also slows the process of digestion to enable more absorption of nutrients. The enzymes secreted by the Ancini cells in the pancreas are normally activated only after they enter the intestinal tract. When chyme is present in the intestine, the intestinal mucosa secrete a different enzyme whose purpose is to activate the Ancini-secreted enzymes. It is important that these (Ancini-secreted) pancreatic enzymes are not activated until they are secreted into the intestine, otherwise, the pancreas would digest itself. The Ancini cells also secrete a substance called trypsin inhibitor which prevents the activation of the digestive enzymes in the pancreas and its ducts.

?When the pancreas becomes severely damaged or when a duct becomes blocked, large quantities of pancreatic secretion sometimes become pooled in the damaged areas of the pancreas. Under these conditions, the effect of trypsin inhibitor is often overwhelmed, in which case the pancreatic secretions rapidly become activated and can literally digest the entire pancreas within a few hours, giving rise to the condition called acute pancreatitis. This sometimes is lethal because of accompanying circulatory shock; even if not lethal, it usually leads to a lifetime of pancreatic insufficiency.?(2)

I bet I have your attention now. What I have described here is a very brief overview of this function and to really appreciate the intricacies we would need to enter into a discussion beyond the scope of this article. Again, I encourage a visit to a good physiology text.

<center>Hormonal Functions of the Pancreas</center>

The most important hormones produced by the pancreas are insulin and glucagon. These are crucial to the regulation and maintenance of normal glucose, lipid, and protein metabolism. These hormones are secreted directly into the blood by the islets of Langerhans. There are one to two million of these islets in the pancreas. These islets have three major types of cells: alpha, which secrete glucagon; beta, which secrete insulin; and delta, which secrete somastatin. The close interrelations of these cells and their proximity to capillaries in the pancreas allow cell-tocell communication (ductless) and direct control of regulation of each of their secretions which in turn allows precise control of their effects on metabolism.

Insulin has the general effect of making the cellular utilization of glucose possible by increasing membrane permeability and by activating receptors in the cell that influence protein, fat and glucose synthesis. This affects almost all tissues (the major exception is brain tissue, discussed later in this article) but particularly the liver, muscles and adipose (fatty) tissues.

In the larger perspective, insulin facilitates glucose transport through muscle cell membranes. It works in concert with growth hormone to promote protein synthesis and storage. In the adult this is most pertinent to tissue repair and healing. Insulin also promotes uptake, storage, and use of glucose in the liver. The release of glucose from the liver is an important factor in maintaining stable blood sugar levels. When glucose levels in the liver are excessive then the excess glucose is converted to triglycerides and stored in adipose tissue and the liver as fat. Therefore, you can understand why increased body fat is an indication of excessive glucose levels and one of the clinical symptoms of alcoholism is fatty liver.

Paradoxically, in the absence of insulin (as in diabetes mellitus) the enzyme lipase becomes strongly activated in fat cells and the stored triglycerides are released as large quantities of fatty acids and glycerol in the blood. This high lipid concentration in the blood?particularly cholesterol? is one of the primary factors in the development of atherosclerosis. Atherosclerosis leads to heart attacks and strokes. Increased levels of fatty acids in the blood also result in a very acidic state called ketosis that can result in coma and death. Chronic overstimulation of insulin production can lead to desensitization of cellular receptors to insulin. This state is called insulin resistance. This is present in metabolic syndrome and is referred to as Type II Diabetes. There is a relationship between insulin resistance and elevated cholesterol levels.

Interestingly, insulin was not isolated from the pancreas until 1922. Prior to that, the prognosis for diabetics was rapid decline and death. Now the prognosis, with treatment compliance, is a healthy normal life. Insulin has always been associated with carbohydrate metabolism and ?blood sugar levels,? but it is the abnormalities of fat metabolism such as arteriosclerosis that are the usual causes of death in diabetics. Also, in poorly managed diabetes, the reduced ability to synthesize protein leads to many cellular function disorders, tissue wasting and an impaired ability to heal wounds or tissue infections which can result in tissue necrosis and amputations.

Unlike other body tissues insulin has almost no effect on glucose uptake in the brain. Brain cells normally use only glucose for energy and they are permeable to glucose without the presence of insulin; and brain cells are only able to utilize glucose from other sources such as fats with great difficulty, so it is essential that blood glucose levels are maintained above a critical level. Below that level hypoglycemic shock develops and proceeds from nervous irritability, to fainting, seizures, and eventually coma. You may begin to understand that people with hypoglycemic problems are also having difficulties with the feedback loops involving insulin and glucagon and the other mechanisms that maintain stable blood glucose levels.

In summary there is a feedback loop between blood glucose levels and insulin secretion, but just as a side note, there is also a feedback loop between blood glucose levels and the sense of hunger.

Insulin, secreted by the pancreas, promotes the utilization of carbohydrates for energy and depresses the utilization of fats. With a lack of insulin there is fat utilization rather than glucose utilization for energy. The trigger that causes a switch to fat utilization is a low glucose level. When blood glucose is high, insulin is secreted and carbohydrates are used for energy instead of fat. Excess blood glucose is stored as liver glycogen, liver fat, and muscle glycogen. The most important function of insulin is to control which of these two sources (carbohydrates or fats) will be used by the cells for energy. This is accomplished within a narrow range and a high degree of moment-to- moment control. That is why it is important to have a diet that promotes stable blood glucose levels. If you are feeling hungry about every two hours you are on the blood sugar roller coaster and your diet and body are not maintaining stable glucose levels.

Glucagon essentially has the opposite effect of insulin and acts to balance the effects of insulin. Low blood glucose (hypoglycemia) triggers an increase in the secretion of glucagon and this raises blood glucose. The most important function of glucagon is to increase blood glucose levels correcting hypoglycemia. The primary way this is accomplished is by stimulating breakdown of liver glycogen (glycogenolysis) and by stimulating glucose production from the liver (glyconeogenesis). These functions have the effect of significantly increasing the availability of glucose to other organs. One of the liver?s functions is that of a blood glucose buffer system. When blood glucose levels are high, for instance when eating a meal, the liver stores a large percentage almost immediately as glycogen. When blood glucose falls between meals, the liver releases glucose back into the blood. In this way it helps stabilize blood glucose so that it is always maintained within normal levels.

Why is this important? Glucose is the only nutrient that can be used by the brain, retina and germinal epithelium of the gonads in levels sufficient to supply them with the energy required for optimal function. Blood glucose levels should be between 80-100 mg/cc. Most of the glucose released from the liver during the periods between meals is used for brain metabolism.

The role of somastatin, the third major hormone secreted by the pancreas, is that of inhibition of several hormones in the intestines including insulin. It assists in regulating the speed of digestion and the action of insulin.

It is worth noting that there are three other hormones in play in this feedback loop/switching mechanism between carbohydrate and lipid metabolism. They are growth hormone, cortisol, and epinephrine. Both cortisol and epinephrine increase when stress levels increase. Higher levels of cortisol and epinephrine result in elevation of blood glucose in another set of interactions with insulin and glucagon. (Consider for a moment how stress, caffeine, and other stimulants affect your blood glucose levels.)

An additional factor worth noting is the effect of glucose in raising osmotic (fluid) pressure in extracellular fluid. High extracellular osmotic pressure results in fluid movement from the cells (thus cellular dehydration), which leads to dieresis (loss of fluid through the kidneys) resulting in dehydration and symptoms of excessive thirst. Excessive thirst is another symptom of diabetes mellitus.

I encourage you to study Type II diabetes (insulin resistance), which is closely related to obesity, a growing problem in the U.S. (Pardon the pun.) This is part of a cascade of disorders referred to as ?metabolic syndrome?. Understanding this will help you assist your clients in living more healthy lifestyles and understanding the importance of a healthy diet and maintaining normal weight.

The final note I would make is purely anecdotal and certainly not supported by research statistics. I have observed that many clients that are undiagnosed or poorly controlled diabetics have extremely dense tough tissue. I have found this to be so consistent that I have been able to use it in my practice as a fairly accurate indicator of those conditions.

<center>Embryologic Development and Location of the Pancreas</center>

The pancreas begins as two separate buds during the fourth week of pregnancy. The dorsal bud arises from the early upper intestine. The ventral bud arises from the stalk of the liver. As these two buds grow they eventually merge into a single pancreatic mass. Both original stalks remain and form the pancreatic duct system with the ventral stalk becoming the major duct and the dorsal stalk the smaller accessory duct. In some people the smaller accessory duct is vestigial or absent. The head and body of the pancreas formed from the ventral bud eventually adhere to the posterior parietal peritoneum and are essentially immobile. The tail formed from the dorsal bud lies in the left omental wall and is more freely moveable. The head of the pancreas is in the C-shaped curve of the duodenum and the tail touches the spleen. There is an old anatomical saying ?the romance of the abdomen is the pancreas lying in the arms of the duodenum.?(3)

The major pancreatic duct lies along the length of the pancreas and is adjacent to the common bile duct as it empties into the duodenum. This duct is how the digestive enzymes are transported to the duodenum.

The pancreas is very vascular and is served by branches of the large splenic, common hepatic and superior mesenteric arteries, and it is drained by the splenic and superior mesenteric veins both of which are direct branches of the hepatic (liver) portal vein.(4)

?The pancreas lies directly below and slightly dorsal to the stomach. It runs horizontally from the left edge of the stomach to a point slightly right of midline and it sits above the umbilicus. It protrudes very anterior as it crosses the vertebral bodies and then sits down on top of the psoas fascia left and right of the spine above an imaginary line drawn horizontal across the abdomen just above the umbilicus.?(5)

?When you gently palpate the pancreas it is pretty fragile. It feels like tapioca or cottage cheese or pomegranate seeds in custard inside a plastic bag.?(6)

<center>Conclusion</center>

At last, I arrive at the point of this article. You now have an understanding of the importance of pancreatic function and where it is located in the abdomen. You also have some sense of adjacent structures, particularly vascular ones, and you should have some sense that it is a fairly delicate organ. The pancreas is much more delicate than the stomach or liver or even the intestines. In 1981, when I was trained, we were told that the abdominal structures just ?moved out of the way? when you were doing psoas work. That is incorrect. We were also trained to work directly on the entire length of the psoas, even up to the respiratory diaphragm.

I have reviewed both of Barral?s books on visceral manipulation and I found no discussion of the pancreas in his first book. In his Visceral Manipulation II there is minimal discussion of pancreatic function and location and an interesting short discussion of pancreatitis. There is a general but brief discussion of diagnostic and VM techniques of the pancreas that are done either by inference from the duodenum and/or sphincter of Oddi; and there is a discussion of a more direct manipulation of the pancreas that essentially involves use of the open hand and palm in a subtle ?following? technique. There is certainly no description of any deep aggressive manipulation especially with the fingertips.(7, 8)

I have come to the conclusion that any direct psoas work or any deep direct tissue work in the abdomen above the umbilicus has a huge potential for injury to the pancreas.(9) You can now understand the potential effects of pancreatic injury. It is quite possible to do subtle gentle visceral manipulation in this area and certainly possible to do indirect work on the psoas. My personal policy is that I do not do any direct psoas work or deep direct manipulation of abdominal structures above the umbilicus. I would like to encourage my SI colleagues to consider this information when doing or teaching any abdominal work, particularly work on the psoas.

Notes

1. I suggest your local library for a good current physiology textbook like Guyton & Hall. These textbooks are expensive to buy and tend to become outdated fairly rapidly with respect to current research.

2. Guyton & Hall, Textbook of Medical Physiology, 11th ed., Elsevier Saunders, Philadelphia, 2006.

3. Guyton, A., Function of the Human Body, 4th ed., WB Saunders Co., Philadelphia, 1974.

4. Langebartel, D.A., The Anatomical Primer?An Embryological Explanation of Human Gross Morphology, University Park Press, Baltimore, 1977. (Sincere thanks to Jeff Burch CAR for introducing me to this rare and wonderful textbook.)

5. Gaggini, L., author?s notes from Visceral Manipulation workshop, Washington 1998.

6. Gaggini, L., quote from discussion of palpation of the pancreas, author?s notes from Visceral Manipulation workshop, Washington, 2001.

7. Barral, J.P., Mercier, P., Visceral Manipulation, Eastland Press, Seattle, 1988.

8. Barral, J.P., Visceral Manipulation II, Eastland Press, Seattle, 1989.

9. Please refer to your favorite anatomy atlas to study or review the location of the pancreas relative to the ribs, psoas, iliac crest, and other anatomical landmarks; and/or check out the illustration at this URL: http://adam.about.com/encyclopedia/Pancreas-and-kidneys.htm.