page_title: Classification of peripheral nerves
section_title: History
hierarchical_section_title: Classification of peripheral nerves / Autonomic nervous system / History
caption_attribution_description: English: Langley's Classification Tree his book "The Autonomic Nervous System" (1921)
context_page_description: The classification of peripheral nerves in the peripheral nervous system groups the nerves into two main groups, the somatic and the autonomic nervous systems. Together, these two systems provide information regarding the location and status of the limbs, organs, and the remainder of the body to the central nervous system via nerves and ganglia present outside of the spinal cord and brain. The somatic nervous system directs all voluntary movements of the skeletal muscles, and can be sub-divided into afferent and efferent neuronal flow. The autonomic nervous system is divided primarily into the sympathetic and parasympathetic nervous systems with a third system, the enteric nervous system, receiving less recognition.
context_section_description: In 1898, British scientist John Newport Langley first coined the term "autonomic" in classifying the connections of nerve fibers to peripheral nerve cells. Previous researchers had utilized different terms such as "the sympathetic nerves" [Winslow et al.] to describe the way in which neurons in one part of the body brought about sympathetic reactions in another part of the body, as well as the "ganglionic nerves and ganglionic nervous system" [Livingstone et al.] for the ganglionic conversion of voluntary to involuntary movements (which supposedly made these peripheral nerves 'ganglionic nerves'), among other classifications. Langley stated that his choice of autonomic was not intended to imply a special degree of independence for the cells at hand, but rather to demarcate a clear departure from previous nomenclature because his hypothesis, while incorporating much previous research, was largely distinct from his predecessors.
  
  Langley rejected that the sympathetic nerves possessed a particular relationship to the 'sympathies,' and aptly pointed out that the presence of ganglial nerves in both the spinal cord and cranium made the 'ganglionic' connections of the peripheral nerves a pointless, if not misleading, term. Instead, he noted that the sympathetic neurons that innervated the entire body tended to have opposing functions to the other autonomic neurons of the tectal and bulbo-sacral regions. The latter two, tectal and bulbo-sacral, were grouped together to form the parasympathetic system because they tended to respond in a like manner to various drugs. Langley also mentions an enteric nervous system in his writing, but this third grouping has largely fallen out of discussion in modern practice.
caption: Langley's Classification Tree from his 1921 book The Autonomic Nervous System
exif: {}