5 anxiety disorders

NORMAL HUMAN NERVOUS SYSTEM 11ture of the nervous system). The study of the body’s function is called physiology,and so, we’ll also be discussing neurophysiology (the function of the nervoussystem).As architects teach us, form follows function. The layout of a building is dictatedin large part by its intended use. A hospital, an airport terminal, a restaurant, ahome, and a factory are each designed to serve a specific purpose. If the building’sdesign does not facilitate its purpose, then it will soon be abandoned.Similarly, the structure of the nervous system is interwoven with its function. Atall levels, from the microscopic highly branched nerve cell to the multiple connectionsbetween large brain regions that are visible to the naked eye, the structure ofthe nervous system is obviously designed to serve its chief purpose: communication.As a result, it is difficult to talk about structure separately from function. Nevertheless,a divided, stepwise approach may help make these complicated matters easierfor you to understand.2.2.1 Neuroanatomy: Structure of the Nervous SystemCentral Nervous System (CNS). The human nervous system is an integratedcommunication network that sends and receives information throughout the body.This network is divided into two main divisions: central nervous system (CNS) andperipheral nervous system (PNS). The CNS is the command center of this networkand is made up of the brain and spinal cord. The PNS is the interface of the nervoussystem with the rest of the body and the external environment. It is comprised ofnerve fibers and small clusters of nerve cells known as ganglia.Neurologists treat nervous system diseases that mainly cause physical symptoms.Therefore, they are concerned with both the CNS and the PNS. Mental health professionals,on the other hand, treat diseases that produce emotional, thought, andbehavioral symptoms. As a result, we are more concerned with the CNS and, inparticular, the brain.The Brain. The brain is the most magnificent of the body’s organs. But then, asmental health professionals, we may all be a little biased. As you study the brain,you learn very quickly that it is highly organized. If you cut the brain like a loaf ofbread, which we can now do visually with computed tomography (CT) and magneticresonance imaging (MRI) scans, there are many structures that are easy to see.We’ll spare you all the details regarding these many brain regions.Over the years, we have learned a great deal about the functions of each of thesestructures. This knowledge has come about in several ways. First, we can look atthe effect of disease or injury in a particular part of the brain. For example, if astroke causes paralysis, then we can assume that the injured part of the brain wasresponsible for movement of the paralyzed body parts. Likewise, if an injury resultsin certain personality changes, then we can assume that the injured part of the braincontributed to those behavioral alterations. One of the best-known examples is theeffect of a stroke upon mood. It is well known that a stroke to the left frontal areaof the brain dramatically increases the likelihood of depression. On the other hand,