GI tract vs epithelial duct

GI tract and epithelial duct both are nouns.

Word	Noun	Adjective	Verb	Adverb
GI tract	Yes	No	No	No
epithelial duct	Yes	No	No	No

As nouns, epithelial duct is a hypernym of GI tract; that is, epithelial duct is a word with a broader meaning than GI tract:

GI tract: tubular passage of mucous membrane and muscle extending about 8.3 meters from mouth to anus; functions in digestion and elimination
epithelial duct: a bodily passage or tube lined with epithelial cells and conveying a secretion or other substance

Other hypernyms of GI tract include canal, channel, duct.

GI tract (noun)	epithelial duct (noun)
tubular passage of mucous membrane and muscle extending about 8.3 meters from mouth to anus; functions in digestion and elimination	a bodily passage or tube lined with epithelial cells and conveying a secretion or other substance