<unk>  is a part of organogenesis in vertebrate embryos. Steps of<unk>  include the formation of the dorsal nerve cord, and the eventual formation of the central nervous system. The process begins when the notochord induces the formation of the central nervous system (CNS) by signaling the ectoderm germ layer above it to form the thick and flat neural plate. The neural plate folds in upon itself to form the neural tube, which will later differentiate into the spinal cord and the brain, eventually forming the central nervous system.
Different portions of the neural tube form by two different processes, called primary and secondary<unk> , in different species.
In primary<unk> , the neural plate creases inward until the edges come in contact and fuse.
In secondary<unk> , the tube forms by hollowing out of the interior of a solid precursor.
Neurulation
Reticular formation
Tissue expansion
Granulation tissue
Desmoplasia
Articular processes
Hyperplasia
Mitosis