One of the British Crown Jewels is the Ampulla, which holds the holy oil used to anoint a new monarch during a coronation. Another ampulla inside us issues fluids less exalted but more important to life. It's called the ampulla of Vater.

In anatomy, ampulla means an enlarged duct or channel. Vater is the last name of Abraham Vater, the German anatomist who discovered this structure. It's also known by the less resonant but more medically descriptive name of the hepatopancreatic ampulla.

Two fluids course through the ampulla of Vater: pancreatic juice, consisting of a variety of digestive enzymes; and bile. Secreted by the liver, bile consists of a variety of alkaline chemicals, pigments and cholesterol. These empty into the duodenum, the beginning of the small intestine, to aid in digestion.

That's not true in everyone; in a large minority of people, the ampulla channels only bile, as the pancreatic duct enters directly into the duodenum.

Food is highly acidic upon entering the duodenum, because it is mixed with hydrochloric acid produced in the stomach. The alkaline bile neutralizes the acid, and a new phase of digestion begins. Bile is a detergent, breaking apart fat into small globules that can be absorbed by the blood-rich lining of the small intestine. Most nutrients are absorbed in the duodenum.

The ampulla is the conductor in this digestive orchestra, ensuring that pancreatic and bile fluids are introduced at the appropriate time. At the end of the ampulla, a muscle called the sphincter of Oddi dilates or contracts as needed to allow the fluids to enter the duodenum. Other sphincters are found at the junction with the gallbladder and the pancreatic duct.

When the sphincter of Oddi is closed, bile drains into the gall bladder. The gall bladder absorbs water from the bile, concentrating it so it is more potent. When food flows from the stomach into the duodenum, a structure at the end of the ampulla of Vater called the sphincter of Oddi opens. With the ampulla open, the pancreatic juices and concentrated bile flow through to meet the food. The sphincter closes to prevent the digested food from entering the ampulla.

A disease called Sphincter of Oddi dysfunction causes the sphincter to remain closed, and pancreatic fluid and bile back up. This condition can cause pancreatitis (inflammation of the pancreas), or pain in the gall bladder like that caused by a diseased gallbladder.

In rare cases, the ampulla of Vater can become cancerous. Also rarely, pancreatic tissue can grow into the ampulla, a condition called ectopic pancreas.

The ampulla of Vater can also be blocked by a gallstone, causing the distress typical of gallstone attacks. Gallstones can be removed by surgery, or in some cases by a drug that causes the gallstones to dissolve.

A poetic account of a gallstone attack and other maladies of the ampulla of Vater was written by Dr. Leslie H. Sobin of the Armed Forces Institute of Pathology, in the style of "The Song of Hiawatha" by Henry Wadsworth Longfellow.

Here's a taste of this medical poetry to whet your appetite:

I: the stone

By the shores of Duodenum

where there flows the River Bile

Rules the Ampulla of Vater

like a Pharaoh on the Nile.

Happy was his tribe of Villi

striving by these shores so green

Fishing for the chylomicron

in a state of peace serene …

You can read it all here: http://tinyurl.com/ytgjte.

Contact staff writer Bradley J. Fikes at (760) 739-6641 or bfikes@nctimes.com.