autonomic ganglion - any of the ganglia of the autonomic system whose unmyelinated fibers innervate the internal organs

nervous system, systema nervosum - the sensory and control apparatus consisting of a network of nerve cells

neural structure - a structure that is part of the nervous system

sympathetic nervous system - originates in the thoracic regions of the spinal cord; opposes physiological effects of the parasympathetic: reduces digestive secretions; speeds the heart; contracts blood vessels

parasympathetic, parasympathetic nervous system - originates in the brain stem and lower part of the spinal cord; opposes physiological effects of the sympathetic nervous system: stimulates digestive secretions; slows the heart; constricts the pupils; dilates blood vessels