The document discusses the structure and function of the nervous system. It describes how the nervous system is divided into the central nervous system (CNS), which includes the brain and spinal cord, and the peripheral nervous system (PNS). The CNS is further divided into grey matter and white matter. The PNS includes sensory and motor divisions. Key cell types that make up nervous tissue are described such as neurons, glial cells, and myelin sheaths. Reflex arcs and examples of reflexes like the patellar reflex are explained. An overview of the spinal cord, spinal nerves, and plexuses is provided. The major regions of the brainstem and diencephalon are outlined along with some of their functions in regulating