Chapter 7: General Information on the Structure of the Nervous System and on Higher Nervous Activity and Its Disorders in Mental Diseases

The nervous system of vertebrates has undergone a long and complex evolution and in man has reached its highest stage of development. The basic structural element of the nervous system in vertebrates and in man is the nerve cell (Fig. 3). Each nerve cell, or neuron, contains cytoplasm, a nucleus, and processes. One fine process, especially long, is called an axon. Nerve impulses pass along axons from the body of a cell to other cells or to innervated organs. Other, shorter processes branch out treelike a short distance from the cell and are called dendrites. Axons of some cells come in contact with dendrites and bodies of other cells to form neuron chains along which nerve impulses are conducted.