Updated on November 10, 2024 Distinguish primary brain vesicles from secondary brain vesicles. What are the respective derivatives of secondary brain vesicles? Primary brain vesicles: Formed when the cranial neural folds fuse and rostral neuropore closes. Includes: Prosencephalon, Mesencephalon, Rhombencephalon Secondary brain vesicles: Formed when the prosencephalon and Rhombencephalon divide Derivatives: Telencephalon – cerebrum Diencephalon...