pylorus

(noun)

The opening in a vertebrate, including humans, at the lower end of the stomach that opens into the duodenum.

Related Terms

Examples of pylorus in the following topics:

  • Pylorospasm and Pyloric Stenosis

    • There is narrowing (stenosis) of the opening from the stomach to the first part of the small intestine known as the duodenum, due to enlargement (hypertrophy) of the muscle surrounding this opening (the pylorus, meaning "gate"), which spasms when the stomach empties.
    • Pyloric stenosis also occurs in adults where the cause is usually a narrowed pylorus due to scarring from chronic peptic ulceration.
    • The gastric outlet obstruction due to the hypertrophic pylorus impairs emptying of gastric contents into the duodenum.
    • This diagram shows the location of the pylorus in relation to the stomach.

  • Gross Anatomy of the Stomach

    • The pylorus or atrium, the lower section of the organ that facilitates the emptying of the contents into the small intestine.
    • This diagram of the stomach shows the cardiac region, fundus, body, and pylorus.

  • Muscularis

    • The pylorus of the stomach has a thickened portion of the inner circular layer: the pyloric sphincter.

  • Microscopic Anatomy of the Stomach

    • The pylorus is surrounded by a thick circular muscular wall that is normally tonically constricted, forming a functional (if not anatomically discrete) pyloric sphincter that controls the movement of chyme.