pylorus

pyloric /puy lawr"ik, -lor"-, pi-/, adj.
/puy lawr"euhs, -lohr"-, pi-/, n., pl. pylori /-lawr"uy, -lohr"uy/. Anat.
the opening between the stomach and the duodenum. See diag. under intestine.
[1605-15; < LL < Gk pylorós lit., gatekeeper]

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      cone-shaped constriction in the gastrointestinal tract that demarcates the end of the stomach and the beginning of the small intestine. The main functions of the pylorus are to prevent intestinal contents from reentering the stomach when the small intestine contracts and to limit the passage of large food particles or undigested material into the intestine.

      The internal surface of the pylorus is covered with a mucous-membrane lining that secretes gastric juices. Beneath the lining, circular muscle tissue allows the pyloric sphincter to open or close, permitting food to pass or be retained. The sphincter remains in an open or relaxed state two-thirds of the time, permitting small quantities of food to pass into the duodenum, the upper portion of the small intestine. When the duodenum begins to fill, pressure increases and causes the pyloric sphincter to contract and close. Muscular contractions (peristaltic waves) in the duodenum then push food deeper into the intestine. Because the pyloric sphincter is relatively narrow, only small amounts of well-emulsified food can pass through it even while it is open. Surgical removal of the valve does not significantly affect the gastric emptying of the stomach. The term pylorus is used to refer to the pyloric sphincter and can also be applied to that portion of the stomach immediately above the pyloric sphincter.

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Universalium. 2010.

Look at other dictionaries:

  • Pylorus — Py*lo rus, n.; pl. {Pylori}. [L., fr. Gr. ? pylorus, gate keeper; ? a gate + ? watcher, guardian.] (Anat.) (a) The opening from the stomach into the intestine. (b) A posterior division of the stomach in some invertebrates. [1913 Webster] …   The Collaborative International Dictionary of English

  • Pylōrus — (gr.), 1) Thürhüter; 2) (Anat.), der Pförtner der untern Magenöffnung. Daher Pylorĭcae arterĭae, P. venae, Arterien u. Venen des Pylorus, s. u. Bauch 2) C) a) bb) …   Pierer's Universal-Lexikon

  • pylorus — 1610s, from L.L. pylorus “the lower orifice of the stomach,” from Gk. pyloros “gatekeeper, porter,” from pyle “gate” (see PYLON (Cf. pylon)) + ouros “watcher, guardian” (see WARRANT (Cf. warrant)) …   Etymology dictionary

  • Pylŏrus — (griech.), Pförtner, s. Magen …   Meyers Großes Konversations-Lexikon

  • Pylorus — Pylōrus (grch.), Pförtner (s. Magen); Pylorusstenōse, Verengerung des Magenpförtners; Pylorusresektion, operative Entfernung des Pförtners, bes. bei Magenkrebs …   Kleines Konversations-Lexikon

  • Pylorus — Pylorus, s. Magen …   Herders Conversations-Lexikon

  • Pylorus — Pylorus, Magenpförtner ⇒ Magen …   Deutsch wörterbuch der biologie

  • pylorus — [pī lôr′əs] n. pl. pylori [pī lôr′ī, pə lôr′ī] [LL < Gr pylōros, gatekeeper < pylē, gate + ouros, watchman] the opening, surrounded by muscular tissue, from the stomach into the duodenum, the first part of the small intestine pyloric… …   English World dictionary

  • Pylorus — Infobox Anatomy Name = PAGENAME Latin = valvula pylori GraySubject = 247 GrayPage = 1164 Caption = Outline of stomach, showing its anatomical landmarks. Caption2 = Interior of the stomach. (Pylorus labeled at center left.) System = MeshName =… …   Wikipedia

  • Pylorus — Der Pylorus (gr. πυλωρός [pylōrós], „Pförtner“[1]) ist die ringförmig angeordnete glatte Muskulatur, die sich zwischen dem Antrum des Magens (Antrum pyloricum) und dem Zwölffingerdarm (Duodenum) befindet. Der Pylorus ist in Ruhe geschlossen. Er… …   Deutsch Wikipedia

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