Summary
The papilla of Vater is involved in the regulation of bile flow (inhibition and facilitation)
into the duodenum and the prevention of reflux into the bile and pancreatic duct system.
These functions are achieved by a special muscular, neural and mucosal structure of
the papilla of Vater. The mucosa of the papilla of Vater consists of a complicated
system of mucosal folds which can function as an anti-reflux valve or might even participate
in the regulation of bile outflow. The smooth muscle of the spincter of Oddi differs
anatomically and embryologically from the surrounding duodenal muscle. It shows spontaneous
electrical and mechanical activity acting independently from the duodenum but integrated
into the overall function of the gastrointestinal tract by myogenic mechanisms, extrinsic
and intrinsic nerves and circulating hormones. A spontaneous myogenic electrical activity
propagates distally and leads to distally propagating phasic contractions. With endoscopic
manometry in humans these phasic contractions as well as basal tone, bile duct pressure
and pancreatic duct pressure can be measured. Changes of the basal tone and the phasic
activity will alter the flow resistance thus regulating bile flow and inducing gallbladder
filling. The most characteristic feature of the sphincter of Oddi is the inhibitory
effect of cholecystokinin, which is a powerful contractor of the gallbladder, on the
sphincter of Oddi motor activity. Cholecystokinin released in response to intra-duodenal
fat and other nutrients might be the physiological stimulus of the increased bile
flow post-prandially. The function of other hormones is still rather speculative and
their physiological significance awaits further confirmation.
Key words:
Sphincter of Oddi - Papilla of Vater - Anatomy - Cholecystokinin - Manometry - Hormones
- Electrical activity - Motility
