anatomical structure vs complex body part

anatomical structure and complex body part both are nouns.

Word	Noun	Adjective	Verb	Adverb
anatomical structure	Yes	No	No	No
complex body part	Yes	No	No	No

As nouns, anatomical structure and complex body part are synonyms defined as:

anatomical structure and complex body part: a particular complex anatomical part of a living thing and its construction and arrangement

Other synonyms of anatomical structure include bodily structure, body structure, structure.

anatomical structure (noun)	complex body part (noun)
a particular complex anatomical part of a living thing and its construction and arrangement	a particular complex anatomical part of a living thing and its construction and arrangement