Question

What constitutes the central and peripheral nervous systems?how are the componnts of central nervous system protected?

Answer 1

The central nervous system (CNS) is the part of the nervous system consisting of the brainand spinal cord. The central nervous system is so named because it integrates information it receives from, and coordinates and influences the activity of, all parts of the bodies of bilaterally symmetric animals—that is, all multicellular animals except spongesand radially symmetric animals such asjellyfish—and it contains the majority of the nervous system. Many consider the retina[2]and the optic nerve (2nd cranial nerve),[3][4] as well as the olfactory nerves (1st) andolfactory epithelium[5] as parts of the CNS, synapsing directly on brain tissue without intermediate ganglia. Following this classification the olfactory epithelium is the only central nervous tissue in direct contact with the environment, which opens up fortherapeutic treatments. [5] The CNS is contained within the dorsal body cavity, with the brain housed in the cranial cavity and the spinal cord in the spinal canal. In vertebrates, the brain is protected by the skull, while the spinal cord is protected by the vertebrae, both enclosed in the meninges.