Gastrointestinal system

A collective term for the digestive and circulatory systems of jellyfish-type coelenterates. This system consists of the mouth (the center of the underside of the body), stomach (an extension following the mouth, also called the coelenteron or gastric cavity), radial aquatic tubes (water tubes extending radially from the stomach to the edge of the umbrella), and annular aquatic tube (water tube continuing from the radial aquatic tube and running in a circular shape around the edge of the umbrella). External fluid (water) circulates within this system, and food is digested between the mouth and stomach and transported by the aquatic tube, and in addition to digestion and circulation, breathing and excretion also take place.

[Masayuki Uchibori]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

腔腸(こうちょう)動物のクラゲ型において消化器官系と循環器官系を総称したもの。この系は、口（体の下面中央部）、胃（口に続く拡張部で、腔腸あるいは胃腔ともいう）、放射水管（胃から傘の縁まで放射状に伸びた水管）、環状水管（放射水管から続いて傘の縁を環状に走る水管）よりなる。この中には外液（水）が循環し、また食物は口から胃までの間で消化され、水管によって運ばれるなど消化、循環が行われるほか、呼吸や排出も行われる。

［内堀雅行］

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