[Age-related characteristics of the myeloarchitectonics of the peripheral nerves]

By means of macromicroscopy and microscopy myeloarchitectonics of morphologically and functionally different somatic and visceral nerves (branches: mandibular nerve, cervical spinal nerves, inferior laryngeal nerve, hepatic plexus) have been studied in 11 age groups. During the prenatal period of ontogenesis asynchronism of myelogenesis is stated in various muscle branches of the nerves, dependent on formation of function in corresponding muscles and muscle groups. As demonstrate investigations on peculiarities of myelogenesis course in the somatic and visceral nerves studied, during the period of pre- and postnatal ontogenesis, its dynamics embraces three stages of myelogenesis, determined by G. B. Stovichek for visceral nerves: productive myelogenesis, stages of stabilization and involution. The stage of productive myelogenesis in the somatic nerves studied lasts up to the end of the adolescent period. Two phases are determined in it: the first lasts up to 2-3 years; the second--up to the end of the adolescent period and is characterized with a complete formation of the myelin fibers spectrum. In the visceral nerves studied increase of general amount of myelin fibers and their differentiation are completed simultaneously during the adolescent age. The stabilization stage of myeloarchitectonics of the nerves studied corresponds to the mature age (I and II periods) and the involution stage--to the elderly (and old) age.