The Fine Structure of the Nervous System.

This is the first atlas of the ultrastructure of the mature nervous system and it is a relatively complete collection of elegant micrographs with an accompanying text. The differing quantity and distribution of perikaryal organelles are compared in pyramidal, Purkinje, and granule cells, neurons from the dorsal root ganglion, and in anterior horn cells. Criteria are listed for the identification of dendrites and axons, as well as for the special characteristics of the axon hillock and node of Ranvier. Considerable space has been given to the illustration of the different types of synapses, especially to their presynaptic and postsynaptic organelles and synaptolemmal membranes. Evidence relating synaptic vesicles to transmitter substances and their possible function is discussed. Protoplasmic and fibrous astrocytes are demonstrated and their possible functions pointed out. Of particular interest is the role that thin astrocytic processes may play in isolating receptive surfaces, thereby preventing axon terminals from influencing