placenta vs vascular structure

placenta and vascular structure both are nouns.

Word	Noun	Adjective	Verb	Adverb
placenta	Yes	No	No	No
vascular structure	Yes	No	No	No

As nouns, vascular structure is a hypernym of placenta; that is, vascular structure is a word with a broader meaning than placenta:

placenta: the vascular structure in the uterus of most mammals providing oxygen and nutrients for and transferring wastes from the developing fetus
vascular structure: a structure composed of or provided with blood vessels

placenta (noun)	vascular structure (noun)
the vascular structure in the uterus of most mammals providing oxygen and nutrients for and transferring wastes from the developing fetus	a structure composed of or provided with blood vessels
that part of the ovary of a flowering plant where the ovules form