Formation of neural tube:
- Ectoderm over notochord thickens – forms neural plate (from primitive node to buccopharyngeal membrane)
- Neural groove appears and deepens
- Neural folds grow towards each other medially and fuse at the 4th somite
- Fusion continues cranially and caudally forming neural tube
- Edges of neural tube form neural crests
- Cranial neural pore closes at 20th somite stage
- Caudal neural pore closes at 25th somite stage
Neural tube forms brain and spinal cord