RT Book, Section A1 Armao, Diane M. A1 Bouldin, Thomas W. A2 Reisner, Howard M. SR Print(0) ID 1173789818 T1 Pathology of the Nervous System T2 Pathology: A Modern Case Study, 2e YR 2020 FD 2020 PB McGraw-Hill Education PP New York, NY SN REISNERPATHOL LK accessmedicine.mhmedical.com/content.aspx?aid=1173789818 RD 2024/03/29 AB The central nervous system (CNS) comprises the brain and spinal cord and is the most complex organ system in the human body. The CNS differs from other organ systems in the variety of functions that it provides and in the localization of these functions to specialized areas of the CNS. The localization of specialized functions means that a relatively small, focal lesion in the CNS can produce a profound deficit, for example, loss of speech. This localization also results in the various populations of neurons within the CNS having unique capabilities and also unique vulnerabilities to disease. For example, Parkinson disease (PD) preferentially affects the neurons of the substantia nigra in the brain stem, while Alzheimer disease (AD) preferentially affects the neurons of the cerebral cortex.