Aspectos morfológicos e histopatológicos da lesão e da regeneração do nervo periférico: uma abordagem ao sistema nervoso somático.

Abstract

Introduction: The Somatic Nervous System (SNS) represents one of the divisions of the Peripheral Nervous System (PNS) and connects target organs such as skin, sensory organs, and all skeletal striated muscles to the Central Nervous System. The correct function of SNS depends on the right development and the adjusted relationship between its cellular components. Objective: This paper aims to describe the molecular and cellular mechanisms related to the development of the components of the SNS, as well as to demonstrate the histological and anatomical aspects. Methodology: A search for articles was carried out in the PubMed database, considering only studies published in English in the last 18 years (2001- 2019). Several descriptors related to embryology, histology, and anatomy of the PNS were used. Results / Discussion: During development, the embryo produces several proteins that induce the differentiation of cells of the neural tube, neural crest and cranial placode into neurons and glial cells. In addition, neurotrophins and semaphorins are essential to induce axonal growth. In this context, these molecules stimulate fasciculation and, consequently, the formation of nerves. During the axonal growth, axons and Schwann cells interact to form myelinated and unmyelinated nerve fibers. Conclusion: Considering that the formation of the cellular components of the SNS depends on the expression of several molecules and cell interaction, the information related to embryology, histology and anatomy of the SNS shown in this article may contribute to a better understanding of the formation, malformation and associated pathological processes to that system.