intrinsic

adjectives

belonging to a thing by its very nature
"form was treated as something intrinsic, as the very essence of the thing"- John Dewey
intrinsic, intrinsical
antonym
extrinsic
situated within or belonging solely to the organ or body part on which it acts
"intrinsic muscles"
intrinsic
is similar to
happening or arising or located within some limits or especially surface
"internal organs"; "internal mechanism of a toy"; "internal party maneuvering"
internal
domain category
the branch of morphology that deals with the structure of animals
anatomy, general anatomy