part of epithelial cell adult midgut cell of proventriculus adult proventriculus epithelial cell adult midgut epithelial cell adult proventriculus epithelial zone 5.5 adult proventriculus zone 5.5 epithelial cell 2024-06-21T10:22:28Z Epithelial cell of the intermediate zone between the fifth and sixth zones of the adult proventriculus epithelium (Zhu et al., 2024). Along with cells from the sixth zone, they secrete the fourth layer of the peritrophic membrane. There are approximately 200 of these cells in the adult proventriculus. FBbt:00059336 PV5.5 cell fly_anatomy.ontology