Relation _DUCT

A duct is the host of an elongate opening. A morphological extension is needed for this definition. The additional axiom restricts duct to anatomy.
Arity: 2
Domain: Material-object
Subrelation-Of: _host
Axioms:
(=> (_Duct ?A ?B)
    (And (Exists (?Y)
                 (And (_Opening ?Y True)
                      (_Elongate ?Y True)
                      (Host-Of ?A ?Y)))
         (Exists (?X ?Y)
                 (And (Material-Object ?X)
                      (Material-Object ?Y)
                      (Connects ?A ?X ?Y)))))