An aggregation of similarly specialized cells and the associated intercellular substance. Tissues are relatively non-localized in comparison to body parts, organs or organ components. As far as distinctions made to now are concerned, the main feature of tissues is self-connexity and being a homogeneous mass (all parts in the same granularity are tissue as well); though, the definition needs extension.
(Slot-Value-Type Tissue Adjacent-To Anatomical-Structure)
(Slot-Cardinality Tissue _Homogeneous 1)
(Slot-Cardinality Tissue _Self-Connected 1)
(=> (Tissue ?Self)
(And (Exists (?A)
(And (Component-Of ?Self ?A)
(Or (Body-Part ?A) (Body-System ?A))))
(Exists (?B)
(And (Element ?Self ?B) (*Specialized-Cell ?B)))
(Exists (?C)
(And (Surrounds ?Self ?C)
(Or (Anatomical-Structure ?C)
(Substance ?C)
(Body-Region ?C))))
(Forall (?D)
(=> (Developmental-Form-Of ?Self ?D)
(Or (Tissue ?D) (Body-Part ?D))))
(Forall (?E)
(=> (Constituent-Material ?Self ?E)
(Or (Tissue ?E) (Substance ?E))))))