Question

2) how do neuroblasts and glioblasts migrate?

3) how do neuroblasts and glioblasts extend their axons to the right place (i.e. what is the name of the morphology responsible for axon guidance).

Answer 1

• a neuroblast / primitive nerve cell is a dividing cell that will develop into a neuron often after a migration phase , the rostral migrating   stream (RMS) is aunique   pathway responsible for transporting new neurons from the ventricular zone - subventricular zone (VZ-SVZ) , stem cell niche through the anterior fore brain to the olfactory bulb .
• the majority of primitivesupporting cells are called glioblasts   /   spongioblasts and are formed by the neuroepithelial cells after the production neuroblasts has ceased . the glioblasts migrate from the neuroepithelial layer to the mantle layer . this cell is mainly found in marginal layer and forms the myelin sheaths around the ascending and descending axons in that layer.

2         the axons of the neurons in the posterior sensory horn behave differently than those in the anterior horn , the posterior horn pentrate the marginal layer    of the cord and then association of neurons   ,     the dendrity   of the posterior   horn grow   peripherially   to   form   the sensory   part   of the    mixed   nerve     ,    their cell bodies   lie   in the   dorsal root   ganglia   .    those   in the anterior    horn   break through    the marginal   zone and   they conduct motor   impulses from   the cord to the muscles.