Lymphatic vessel - Lymphatic vessel

Japanese: リンパ管 - リンパかん（英語表記）lymphatic vessel

Lymphatic vessels. The lymphatic capillaries at the origin are similar to blood capillaries, but are thicker and have ampullations in various places. They join together to form a lymphatic network. The lymphatic vessels emerging from these have lymphatic valves, and many of them connect with each other to form lymphatic plexuses, which gradually merge to form the main trunk and flow in the same direction as veins. The structure is roughly similar to that of veins, but small lymphatic vessels lack the tunica media, and even large lymphatic vessels are thinner than veins, with fewer longitudinal muscles in the tunica adventitia. The valves are semilunar valves made of folds in the tunica intima, and serve to prevent lymph from flowing backwards. Usually, two of them face the duct wall, and appear swollen from the outside. For this reason, if lymph stagnates in the duct due to lymphangitis or other reasons, a jelly-like bulge forms and can be felt from outside the body.

Source: Encyclopaedia Britannica Concise Encyclopedia About Encyclopaedia Britannica Concise Encyclopedia Information

Japanese:

リンパの導管をいう。起始部の毛細リンパ管は毛細血管と似ているが，これよりも太く，各所に膨大部があって，互いに結合して毛細リンパ管網をつくっている。ここから出るリンパ管はリンパ管弁をもち，多くは互いに連絡してリンパ叢をつくり，次第に合流して本幹となって静脈と同じ方向に流れる。構造はだいたい静脈に似ているが，小リンパ管では中膜を欠き，大リンパ管でも静脈の場合より薄く，外膜の縦走筋も少い。弁は内膜のひだから成る半月弁で，リンパの逆流を防ぐ働きをする。通常2個ずつ管壁に対立し，外面からはふくれて見える。このため，リンパ管炎などでリンパが管内に滞ると，じゅず状のふくれができ体外から触れることができる。

出典　ブリタニカ国際大百科事典小項目事典ブリタニカ国際大百科事典小項目事典について　情報

<<: Lymphangitis - Lymphangitis

>>: Lymph - Lymph axilla