part of overlaps proventriculus proventriculus intermediate layer recurrent wall of the cardia proventriculus recurrent layer The intermediate layer of the proventriculus, with the posterior region derived from the ectodermal foregut and the anterior region from the midgut. The foregut region extends from the apex to the neck of the valve and can be divided into 3 zones of epithelium according to cellular morphology. The midgut epithelium is characterized by the presence of a prominent brush border on the apical surface, instead of the cuticle that marks the foregut. fly_anatomy.ontology FBbt:00005754 midgut epithelium gut epithelial section foregut epithelium