| Sphincter of Oddi | |
|---|---|
 Interior of the descending portion of the duodenum, showing bile papilla | |
| Details | |
| System | Digestive system |
| Location | Surrounds theMajor duodenal papilla |
| Function | A circular muscle (sphincter) that controls the secretion of pancreatic juices and bile into the duodenum, and prevents reflux from the duodenum. |
| Identifiers | |
| Latin | m. sphincter ampullae |
| Acronym(s) | SO |
| MeSH | D009803 |
| TA98 | A05.8.02.018 |
| TA2 | 3112 |
| FMA | 15077 |
| Anatomical terminology | |
Thesphincter of Oddi (alsohepatopancreatic sphincter orGlisson's sphincter), abbreviated asSO,[1] is a muscular valve that, in humans and some animals, controls the flow ofbile andpancreatic juice out of the gallbladder and pancreas respectively through theampulla of Vater into the second part of theduodenum. It is named afterRuggero Oddi.
The sphincter of Oddi is a circular muscle band (sphincter) that surrounds themajor duodenal papilla.[2]
The sphincter regulates the secretion of pancreatic juice and bile into the duodenum.[3] It also prevents reflux of duodenal contents into the ampulla of Vater.[4] By preventing reflux of the contents of the duodenum, the sphincter of Oddi prevents the accumulation of particulate matter and sludge in the bile ducts, reducing the risk ofcholangitis. The sphincter of Oddi also allows retrograde filling of the gallbladder.[5]
The sphincter of Oddi is relaxed by the hormonecholecystokinin[6][7] viavasoactive intestinal peptide.[8]
Pancreatitis can result from a failure of pancreatic secretions to drain properly. One possible cause of impaired drainage of pancreatic juice is blockage of the sphincter of Oddi. A common cause of blockage is agallstone in thecommon bile duct.[citation needed]
Opiates may cause spasms of the sphincter of Oddi, leading to increased serum amylase levels.[9]
The sphincter was described for the first time byRuggero Oddi when he was a young student in 1887.[10] This description followed extensive research into the physiology of dogs and detailedhistological examinations of humans and many other species.[1]
In many mammals (includingmice,guinea pigs,dogs, andopossums), thesmooth muscle around theampulla of Vater does not form a sphincter.[11]
