Editing Nerve (section)

{{short description|Cable-like bundle of axons}}
{{About|anatomical nerve fiber bundle}}
{{Infobox nerve
| Name = Nerve
| Latin = nervus
| Image = 1319 Nerve StructureN.jpg
| Caption = Cross-section of a nerve
| System = [[Nervous system]]
}}

A '''nerve''' is an enclosed, cable-like bundle of nerve fibers (called [[axon]]s). Nerves have historically been considered the basic units of the peripheral nervous system. A nerve provides a common pathway for the [[Electrochemistry|electrochemical]] nerve impulses called [[action potential]]s that are transmitted along each of the [[axon]]s to peripheral organs or, in the case of [[sensory nerve]]s, from the periphery back to the [[central nervous system]]. Each axon is an extension of an individual [[neuron]], along with other supportive cells such as some [[Schwann cell]]s that coat the axons in [[myelin]]. 

Each axon is surrounded by a layer of connective tissue called the [[endoneurium]]. The axons are bundled together into groups called [[Nerve fascicle|fascicles]], and each fascicle is wrapped in a layer of connective tissue called the [[perineurium]]. The entire nerve is wrapped in a layer of connective tissue called the [[epineurium]]. Nerve cells (often called neurons) are further classified as either [[Sensory neuron|sensory]] or [[Motor neuron|motor]].

In the [[central nervous system]], the analogous structures are known as [[nerve tract]]s.<ref name="Purves"/><ref name="Marieb">{{cite book |vauthors=Marieb EN, Hoehn K |title=Human Anatomy & Physiology |url=https://archive.org/details/humananatomyphys0000mari_r3o8 |url-access=registration |edition=7th |publisher=Pearson |pages=388–602 |year=2007 |isbn=978-0-8053-5909-1 }}</ref>