Introductive Chapter of the Autonomic Nervous System

Abstract

The Autonomic Nervous System (ANS) comprises a vast neuronal network topographically distributed in different regions of the central nervous system, defined as the Central Autonomic Network, and the peripheral nervous system. The ANS collects internal and external information (afferents) to integrate them and promote coordinated biological responses (efferents) to preserve the human body’s homeostasis in rest and stressful conditions. The dense ANS network of relationships with peripheral organs makes it a pivotal contributor to every physiological and pathological human process. Therefore, autonomic manifestations are remarkably frequent and ubiquitous in medicine yet often neglected. Indeed, many neurological (e.g., multiple sclerosis and headache) and non-neurological (e.g., diabetes and obstructive sleep apnoea syndrome) conditions comprise ANS manifestations among a constellation of different clinical symptoms and signs. Nonetheless, there are a few disorders where ANS dysfunction is critical (e.g., transitory loss of consciousness, neurodegenerative disorders, and autonomic neuropathies).

In this chapter, we will briefly review the ANS’s anatomical, physiological, and pathological basis. Additionally, we will underline the importance of a systematic evaluation (medical history, examination, and instrumental investigations) to diagnose autonomic dysfunction accurately.