Sympathetic Nervous System

The sympathetic nervous system (SNS) is one of the divisions of the autonomic nervous system that controls the function of organs and glands in the body (efferent portion) and senses changes in these visceral systems (afferent portion). The other division of the autonomic nervous system is the parasympathetic nervous system (PNS). The neurons comprising the efferent SNS arise from the thoracic and lumbar portions of the spinal cord (with the SNS also called the thoracolumbar division). Sympathetic fibers originating from the thoracic cord innervate organs of the head, neck, chest, and upper abdomen. Sympathetic fibers originating from the lumbar cord innervate the lower gastrointestinal (GI) tract and organs of the pelvis.

Keywords: autonomic nervous system; central nervous system; parasympathetic nervous system; peripheral nervous system; enteric nervous system