The brain is developed from the full-filled vesicles walls. Those walls have two layers which are called ventricular and marginal zone. The developing of neuronal structure from walls consists of three parts. Cell proliferation is the key to issue growth because it is chain of events where one cell divides into two individual cells and therefore the amount of cell increases. These cells that divides into two are named radial glial. Those cells give birth to cerebral cortex’s neurons and astrocytes. It requires that DNA be copied. The other born cell continues diving and the other goes to its position on the cerebral cortex. The divided cell is called daughters. Dividing repeats until all the needed parts are generated.
The second part is cell migration. In this part immature neurons called precursor cells wander away from ventricular zone to create new layers. The cortex includes five different layers that gets their birth from radial glials. The third part is cell differentiation. It gives each cell types their own appearance and characteristics. That enables cells to have different functions. First, the neurons differ, after this astrocytes and last oligodendrocytes.
One interesting topic about the chapter was the regeneration of mammal’s and frog’s CNS axons. I have known that human cannot grow CNS axons if they have been damaged but the new thing was that there are species, which are able to do that, for example frogs. There are few reasons why people are not capable for that and maybe the interesting one was the effect of myelin in axon growth – we have used to think that myelin on the axon is only a good thing, but now I know the drawback of it.
