# Sphincters --- **Sphincters** are rings of muscles that open or close different openings or tubes in the body to allow or block passage of substances. ## Sphincters of the Digestive System There are six sphincters of to the [[digestive system]]: - upper esophageal sphincter (UES) - [[stomach|lower esophageal sphincter]] (LES) (sometimes called the gastro-esophageal sphincter, or the cardiac sphincter) - [[stomach|pyloric sphincter]] - sphincter of oddi (hepatopancreatic sphincter?) - illeocecal sphincter - anal sphincter ## Other Sphincters There are two other "bonus" sphincters in the body: - urethral sphincter - iris sphincter (in your eye) ___