With certain exceptions, such as local axon reflexes, most visceral reflexes are mediated through the central nervous system (CNS). VISCERAL AFFERENT FIBERS. The afferent fibers from visceral structures are the first link in the reflex arcs of the autonomic system.
Postganglionic autonomic nerves generally are nonmyelinated motor nerves to skeletal muscles are myelinated.Many autonomic nerves form extensive peripheral plexuses such networks are absent from the somatic system.
Somatic nerves contain no peripheral ganglia, and the synapses are located entirely within the cerebrospinal axis.
Goodman and Gilman Manual of Pharmacology and Therapeutics Section II