The document summarizes the nervous system. It describes the nervous system as having two main parts: the central nervous system comprising the brain and spinal cord, and the peripheral nervous system comprising cranial and spinal nerves. It provides examples of two medical suffixes - "phasia" meaning speech and "trophic" pertaining to development. It gives dysphasia and amyotrophic lateral sclerosis as examples of disorders involving these suffixes. The conclusion states that the nervous system is complex and damage can lead to many diseases.