pyloric sphincter


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Related to pyloric sphincter: pyloric stenosis, cardiac sphincter, Esophageal sphincter

sphincter

 [sfingk´ter]
a circular muscle that constricts a passage or closes a natural orifice. When relaxed, a sphincter allows materials to pass through the opening. When contracted, it closes the opening. Four main sphincter muscles along the alimentary canal aid in digestion: the cardiac sphincter, the pyloric sphincter, and two anal sphincters. Other sphincters are found in the iris of the eye, the bile duct (sphincter of Oddi), the urinary tract, and elsewhere.
anal sphincter (sphincter a´ni) either of two sphincters (the internal and external anal sphincters) that open and close to control evacuation of feces from the anus.
cardiac sphincter a sphincter between the esophagus and the stomach, opening at the approach of food that can then be swept into the stomach by rhythmic peristaltic waves.
sphincter of Oddi a sheath of muscle fibers investing the associated bile and pancreatic passages as they traverse the wall of the duodenum.
pyloric sphincter a sphincter at the opening from the stomach into the duodenum; it is usually closed, opening only for a moment when a peristaltic wave passes over it.
urinary sphincter, artificial a fluid-filled system that surrounds the urethra with a silicone cuff that functions as a sphincter; a pump is in the scrotum and a fluid reservoir is in the abdomen. For urination, the pump's release valve is squeezed to allow the fluid to leave the urethral cuff and return to the reservoir; after urination is complete, the pump is squeezed and the fluid returns to the cuff to occlude the urethra.

py·lor·ic sphinc·ter

[TA]
a thickening of the circular layer of the gastric musculature encircling the gastroduodenal junction.

pyloric sphincter

n.
A ring of smooth muscle fibers around the opening of the stomach into the duodenum.

pyloric sphincter

a sphincter at the opening from the stomach into the duodenum. It is usually closed, opening only for a moment when a peristaltic wave passes over it. Also called pyloric valve.

py·lor·ic sphinc·ter

(pī-lōr'ik sfingk'tĕr) [TA]
A thickening of the circular layer of the gastric musculature encircling the gastroduodenal junction.
Synonym(s): musculus sphincter pyloricus [TA] .

pyloric sphincter

a ring of smooth muscle surrounding the opening of the PYLORIC end of the stomach into the intestine. The sphincter prevents the premature escape of food from the stomach into the intestine before it is properly digested. Constriction of the sphincter (pyloric stenosis) is well known in young children, a condition recognised by explosive vomiting. Compare CARDIAC SPHINCTER.