vitelline sac vs vesicula umbilicus

vitelline sac and vesicula umbilicus both are nouns.

Word	Noun	Adjective	Verb	Adverb
vitelline sac	Yes	No	No	No
vesicula umbilicus	Yes	No	No	No

As nouns, vitelline sac and vesicula umbilicus are synonyms defined as:

vitelline sac and vesicula umbilicus: membranous structure that functions as the circulatory system in mammalian embryos until the heart becomes functional

Other synonyms of vitelline sac include umbilical vesicle, yolk sac.

vitelline sac (noun)	vesicula umbilicus (noun)
membranous structure that functions as the circulatory system in mammalian embryos until the heart becomes functional	membranous structure that functions as the circulatory system in mammalian embryos until the heart becomes functional