In vertebrate embryo
the tissue that develops into the CNS is recognized as a fluid filled tube that goes under three swellings at the anterior end that will develop into the forebrain, midbrain, and hindbrain.
The forebrain and hindbrain swellings
grow into two different swellings; creating five total.
5 brain divisions
Telencephalon - > diencephalon - > mesencephalon/midbrain - > metencephalon - > myelencephalon/medulla.
Telencephalon
goes under the most growth
other 4 divisions
make up the brain stem