Microscopical Buildup of the Nervous System

Abstract

The light-microscopical buildup of the various parts of the nervous system is described. The cerebral cortex contains pyramidal cells, spiny non-pyramidal cells and aspiny non-pyramidal cells, stellate or granule cells, fusiform cells, horizontal cells of Cajal, and cells of Martinotti. The parcellation of the cerebral cortex defined as architectonics is based on cytoarchitectonics, myeloarchitectonics, pigmentarchitectonics, angioarchitectonics, chemoarchitectonics, dendrite architectonics, glia architectonics, receptor architectonics, and in vivo architectonics. The layering of the cortex is described. The concepts of minicolumns, granular cortex, agranular cortex, supragranular layers (I, II, and III), infragranular layers (V and VI), heterotypic cortex, and homotypic cortex are presented. Various features of interneurons are described. The hippocampus is a bilaminar structure made up of the cornu ammonis (hippocampus proper) and the dentate gyrus (fascia dentata). Their strata, i.e., alveus, stratum oriens, stratum pyramidale with CA1, CA2, CA3, CA4, stratum radiatum, stratum lacunosum, and stratum moleculare of the cornu ammonis and the stratum moleculare, stratum granulosum, and polymorphic layer of the dentate gyrus are characterized. The following description includes the entorhinal cortex, nucleus basalis Meynert, amygdala, white matter, basal ganglia (i.e., caudate nucleus and putamen, globus pallidus), nucleus accumbens, diencephalon with thalamus made up of various nuclear groups, hypothalamus, the medial hypothalamic region, mesencephalon with the substantia nigra and nucleus ruber, pons with the locus coeruleus, medulla oblongata with the area postrema, pyramis, and inferior olivary complex. The cerebellum is composed of the cerebellar cortex (with granular cells, Golgi cells, Purkinje cells, basket cells, and stellate cells), cerebellar white matter, and cerebellar nuclei embedded in the white matter (dentate nucleus, emboliform nucleus, and fusiform nucleus). The spinal cord is made up of gray matter (dorsal horn, ventral horn, and lateral horn) surrounded by white matter. Ventricles are lined by a single layer of cuboidal ependymal cells with numerous microvilli on the ventricular side. The choroid plexus is a villous structure made up of a single layer of cuboidal epithelium which rests on a basal lamina.