ANATOMICAL AND HISTOLOGICAL ASPECTS OF THE EVOLUTIONARY MORPHOLOGY OF THE SPINAL NODES OF VERTEBRATES ANIMALIUM

Using anatomical, histological, neurohistological and morphological research methods, the histomorphology of spinal cord nodes in a comparative anatomical series of vertebrates: bony fishes, amphibians, reptiles, birds and mammals, which differ in their motor activity and their place of existence in a certain environment, was clarified in the work. It has been established that in the process of phylogenesis, a certain structural and morphofunctional reorganization of the spinal nodes occurs. They differ in shape and size. Adaptation to various living conditions of animals was formed on the basis of changes in the density and size of neurocytes, an increase in the total number of gliocytes and perineuralneglia cells, and polymorphism in the degree of chromatophilia. Thus, according to neurohistological studies, it has been noted that the neurons of the spinal cord nodes of cold-blooded animals (pond frog, pond lizard) are characterized by a functional degree of relative polymorphism – chromatophilia. Impregnation of spinal cord nodes with silver nitrate in all studied animals revealed different intensity of staining of nerve cells (light, light-dark, dark), which is related to the specifics of species and age-related neuromorphology, the morpho-functional state of the nervous system and the type of higher nervous activity. An important issue of modern neuromorphology of animals is the  study  of  spinal  cord nodes,  which play an important role as primary centers on the way to transmit sensory information from receptors to the central nervous system, providing appropriate reactions to the action of certain factors. The scientific article uses material that is a fragment of the research work of the adjacent departments "Development, morphology and histochemistry of  animal  organs in normal  and pathological conditions", state registration number – 0120U100796. The obtained results of the research have an important general biological significance, which complements and expands the idea of certain regularities of spinal nodes,  which relate  to  their structural organization and comparative characteristics at the cellular and tissue levels in vertebrate animals of various species.