part of adult foregut epithelium adult proventriculus intermediate layer adult proventriculus epithelium adult proventriculus epithelial zone 3 2024-06-21T09:01:24Z PV3 region fly_anatomy.ontology The section of the adult foregut epithelium inside the proventriculus that occupies the neck of the cardial valve (King, 1988). It is the distalmost segment of the foregut epithelium inside the proventriculus. FBbt:00059326