vitelline sac vs umbilical vesicle

vitelline sac and umbilical vesicle both are nouns.

Word	Noun	Adjective	Verb	Adverb
vitelline sac	Yes	No	No	No
umbilical vesicle	Yes	No	No	No

As nouns, vitelline sac and umbilical vesicle are synonyms defined as:

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

Other synonyms of vitelline sac include vesicula umbilicus, yolk sac.

vitelline sac (noun)	umbilical vesicle (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