The document summarizes key aspects of the central nervous system, peripheral nervous system, spinal cord, and autonomic nervous system. It explains that the central nervous system includes the brain and spinal cord, and the peripheral nervous system is outside these and includes the somatic and autonomic systems. The spinal cord communicates with senses and muscles, and contains gray matter for cell bodies and white matter for axons. The autonomic nervous system controls organs and is divided into the sympathetic and parasympathetic systems for activation and relaxation.