All body systems are essential the body, and the nervous system is no different. Many times the nervous system is looked over when thinking about the body because the nervous system is not seen. It is seen though every time an animal's heart beat or arm moves. The mammalian nervous system is divided into two parts the Central Nervous System and the Peripheral Nervous System.
The central nervous system also known as CNS refers to the brain and spinal cord. The CNS is encased completely in the skull and the vertebral column for its protection. Both the brain and spinal cord are also covered by the meninges. The meninges are membranes that cover the CNS from the rest of the body. The Pia Matter, Arachnoid Matter, and the Dura Matter make up the three layers from the outside in. Meningitis is inflammation of these layers covering the brain and spinal cord. Meningitis is usually taken seriously because of its close proximity to the CNS.
The peripheral nervous system also known as the PNS includes communication between the brain and/or spinal cord to the organs, muscles, and glands. These are all the nervous outside of the CNS including the cranial nerves, spinal nerves, and autonomic nerves. All of these nervous together make it possible to the brain to tell the body what to do. It is not just a one-way street. The nerves also use the PNS to send signals to the brain to induce a response.