mesenteric vein vs vena

mesenteric vein and vena both are nouns.

Word	Noun	Adjective	Verb	Adverb
mesenteric vein	Yes	No	No	No
vena	Yes	No	No	No

As nouns, vena is a hypernym of mesenteric vein; that is, vena is a word with a broader meaning than mesenteric vein:

mesenteric vein: a tributary of the portal vein passing from the intestine between the two layers of mesentery
vena: a blood vessel that carries blood from the capillaries toward the heart

Other hypernyms of mesenteric vein include vein, venous blood vessel.

mesenteric vein (noun)	vena (noun)
a tributary of the portal vein passing from the intestine between the two layers of mesentery	a blood vessel that carries blood from the capillaries toward the heart