part of capable of material entity embryonic/larval proventriculus outer layer embryonic/larval midgut cell somatic cell of embryonic/larval proventriculus larval secretory cell of the proventriculus 2014-08-13T17:35:34Z fly_anatomy.ontology FBbt:00110920 larval secretory cell of cardia PR cell Secretory cell of the larval proventriculus that synthesizes and secretes the peritrophic membrane. They are part of the outer layer of the proventriculus, near the anterior end. They have large secretory granules and a highly polarized secretory apparatus. secretion