Development of spinal cord (alar and basal plate) : easy and brief description

Development of spinal cord 

Nervous tissue (brain and spinal cord ) is developed from neuroectoderm 

Neuroectoderm is developed from ectoderm 

Part of ectoderm is thickened and form neuroectoderm 

Neuroectoderm detouch from the ectoderm and formed a tube , know as neural tube.

Its cranial end dilated and formed brain and its caudal end remain narrow formed spinal cord .

What is the microscopic structure of neural tube? 

Ans: It is formed by simple columnar epithelium known as neuroepithelium .

From neuroepithelium new neuroblasts are formed by mitosis, they formed a separate layer around the neural tube known as mantle layer .

 Processes, axon and dendrites are begin grow from neuroblast , makes a new later around the mantle layer, known as marginal layer

Again mantle layer is divided into four part.Two ventral part, known as basal plates and

 two dorsal part known as alar part. 

These parts are separated by a sulcus known as sulcus limitans 

Two basal plates are separated by roof plate 

Two alar plates are separated by floor plate 

Basal plates are formed anterior horn of gray matter 

Alar plates are formed posterior horn of gray matter 

So, whole gray matter is came from mantle layer 

white matter is came from marginal layer 

and origin neuroepithelium is converted into ependyma of central canal 

And lumen of neural tube converted into central canal