title: Oogenesis in Campodea sp. (Insecta, Diplura): chorion formation and the ultrastructure of follicle cells.
abstract: During advanced vitellogenesis the follicle cells of Campodea sp. are well developed and contain numerous electron-dense secretory vacuoles. In the postvitellogenic phase the contents of these vacuoles are released from follicle cells and give rise to a thin chorion on the oocyte surface. Concurrently, segregation of yolk spheres takes place in the ooplasm: small spheres migrate to the oocyte periphery and come to lie in the so-called peripheral zone of cytoplasm, whereas large spheres remain in the cell centre.
mesh_terms: D000818:Animals; D002823:Chorion; D005260:Female; D007313:Insecta / Q000033:anatomy & histology / Q000502:physiology*; D009865:Oocytes / Q000648:ultrastructure*; D009866:Oogenesis; D010063:Ovum / Q000648:ultrastructure*