ABSTRACT
The autonomic nervous system is subdivided into sympathetic and parasympathetic components. Both systems distribute their axons via autonomic ganglia* which act as peripheral relay stations. Preganglionic neurons are located in either visceral efferent nuclei in the brainstem or lateral grey columns of the spinal cord. The alternative names for the sympathetic and parasympathetic systems are the thoraco-lumbar and cranio-sacral outflows, respectively. Their axons pass to autonomic ganglia where they synapse on postganglionic neurons
which are motor to smooth or cardiac muscle or the secretory ducts and acini of exocrine glands.
