The sphincter of Oddi (also hepatopancreatic sphincter or Glisson's sphincter), abbreviated as SO,
is a muscular valve that in some animals, including humans, controls the flow of digestive juices (
bile
Bile (from Latin ''bilis''), or gall, is a dark-green-to-yellowish-brown fluid produced by the liver of most vertebrates that aids the digestion of lipids in the small intestine. In humans, bile is produced continuously by the liver (liver bi ...
and
pancreatic juice) out of the pancreas through the
ampulla of Vater
The ampulla of Vater, also known as the or the hepatopancreatic duct, is formed by the union of the pancreatic duct and the common bile duct. The ampulla is specifically located at the major duodenal papilla.
The ampulla of Vater is an imp ...
into the second part of the
duodenum
The duodenum is the first section of the small intestine in most higher vertebrates, including mammals, reptiles, and birds. In fish, the divisions of the small intestine are not as clear, and the terms anterior intestine or proximal intestine m ...
. It is named after
Ruggero Oddi
Ruggero Oddi (July 20, 1864 – March 22, 1913) was an Italian physiologist and anatomist who was a native of Perugia. He is most well known for the Sphincter of Oddi, which was named after him.
Biography
He studied medicine at Perugia, Universi ...
.
Structure
The sphincter of Oddi is a circular muscle band (
Sphincter
A sphincter is a circular muscle that normally maintains constriction of a natural body passage or orifice and which relaxes as required by normal physiological functioning. Sphincters are found in many animals. There are over 60 types in the h ...
) that surrounds the
major duodenal papilla.
Function
The sphincter regulates the secretion of pancreatic juice and bile into the duodenum. It also prevents reflux of duodenal contents into the ampulla of Vater.
The sphincter of Oddi is relaxed by the hormone
cholecystokinin
Cholecystokinin (CCK or CCK-PZ; from Greek ''chole'', "bile"; ''cysto'', "sac"; ''kinin'', "move"; hence, ''move the bile-sac (gallbladder)'') is a peptide hormone of the gastrointestinal system responsible for stimulating the digestion of fat an ...
via
vasoactive intestinal peptide
Vasoactive intestinal peptide, also known as vasoactive intestinal polypeptide or VIP, is a peptide hormone that is vasoactive in the intestine. VIP is a peptide of 28 amino acid residues that belongs to a glucagon/secretin superfamily, the lig ...
.
Clinical significance
Opiates may cause spasms of the sphincter of Oddi, leading to increased serum amylase levels.
History
The sphincter was described for the first time by
Ruggero Oddi
Ruggero Oddi (July 20, 1864 – March 22, 1913) was an Italian physiologist and anatomist who was a native of Perugia. He is most well known for the Sphincter of Oddi, which was named after him.
Biography
He studied medicine at Perugia, Universi ...
when he was a young student in 1887.
This description followed extensive research into the physiology of dogs and detailed
histological
Histology,
also known as microscopic anatomy or microanatomy, is the branch of biology which studies the microscopic anatomy of biological tissues. Histology is the microscopic counterpart to gross anatomy, which looks at larger structures vis ...
examinations of humans and many other species.
Other animals
In many mammals (including
mice
A mouse ( : mice) is a small rodent. Characteristically, mice are known to have a pointed snout, small rounded ears, a body-length scaly tail, and a high breeding rate. The best known mouse species is the common house mouse (''Mus musculus'' ...
,
guinea pigs
The guinea pig or domestic guinea pig (''Cavia porcellus''), also known as the cavy or domestic cavy (), is a species of rodent belonging to the genus '' Cavia'' in the family Caviidae. Breeders tend to use the word ''cavy'' to describe the a ...
,
dogs
The dog (''Canis familiaris'' or ''Canis lupus familiaris'') is a domesticated descendant of the wolf. Also called the domestic dog, it is derived from the extinct Pleistocene wolf, and the modern wolf is the dog's nearest living relative. ...
, and
opossums
Opossums () are members of the marsupial order Didelphimorphia () endemic to the Americas. The largest order of marsupials in the Western Hemisphere, it comprises 93 species in 18 genera. Opossums originated in South America and entered North A ...
), the
smooth muscle
Smooth muscle is an involuntary non- striated muscle, so-called because it has no sarcomeres and therefore no striations (''bands'' or ''stripes''). It is divided into two subgroups, single-unit and multiunit smooth muscle. Within single-unit ...
around the
ampulla of Vater
The ampulla of Vater, also known as the or the hepatopancreatic duct, is formed by the union of the pancreatic duct and the common bile duct. The ampulla is specifically located at the major duodenal papilla.
The ampulla of Vater is an imp ...
does not form a sphincter.
References
Further reading
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{{Authority control
Digestive system
Gallbladder