vitelline sac vitelline circulation • vitellogene · · · Info · Definitions · Synonyms · Characters · · vitelline sac · · Text Common · · Latin · · Scripts 13 · · Length 4 · · Syllables Definitions · · · (noun) membranous structure that functions as the circulatory system in mammalian embryos until the heart becomes functional. Synonyms: yolk sac, vitelline sac, umbilical vesicle, vesicula umbilicus. · · Noun Definition 1 Synonyms · · · yolk sac · · Synonym 1 umbilical vesicle · · Synonym 2 vesicula umbilicus · · Synonym 3 Characters · · space U+0020 a latin small letter a U+0061 c latin small letter c U+0063 e latin small letter e U+0065 i latin small letter i U+0069 l latin small letter l U+006C n latin small letter n U+006E s latin small letter s U+0073 t latin small letter t U+0074 v latin small letter v U+0076