A Snapshot of the Nervous System

The nervous system enables humans to process and respond to external and internal information. It is comprised of two major components: the central nervous system (CNS) and the peripheral nervous system (PNS). The CNS includes the brain and spinal cord, which are both enclosed in bone (the skull and the vertebrae) and surrounded by cerebrospinal fluid (CSF). The PNS consists of spinal nerves (originating from the spinal cord) and cranial nerves (originating from the brain), as well as ganglia, which are groups of nerve cells located outside of the CNS. Spinal nerves have a motor nerve root and sensory nerve root, which meet to form a single nerve. The PNS transmits information to the CNS through afferent nerves, which primarily pass along sensory information, and from the CNS through efferent nerves, which primarily deliver motor commands (for example, the command to contract a muscle). There are more than 100 billion nerve cells in the PNS. Functionally, the PNS is organized into two divisions: Understanding and Managing Peripheral Neuropathy