Central Neural System (CNS)

The central neural system (CNS) is made up of the brain and the spinal cord, and both structures get real physical protection: they sit inside bone (the skull for the brain, the vertebral column for the spinal cord) and are further wrapped by three connective-tissue membranes called the cranial and spinal meninges. During embryonic development, the entire CNS develops from the outermost of the three primary germ layers, the ectoderm — the same layer that also gives rise to the skin, which is a useful way to remember why the nervous system and skin share a developmental origin. The sec …