Question

What is a fascicle in a nerve?

Answer 1

A fascicle or fasciculus in a nerve cell is a bundle of funiculi. A funiculus is a small bundle of nerve fibres (axons). A small nerve may composed of a single funiculus, but a larger nerve is composed of several funiculi collected together into larger bundles, which are known as fasciculi.

Each cranial and spinal nerve contains layers of protective connective tissue coverings. Each axon is wrapped in a layer known as endoneurium. Groups of axons along with their endoneurium are collected together in bundles called as fascicles. Each of these fascicles are wrapped in a protective layer called as perineurium. Groups of fascicles with their perineurium are collected together to form an entire nerve, which is wrapped by a superficial covering called as epineurium. Within the perineurium and epineurium, several blood vessels are present, which nourish the nerves.

A nerve fascicle is a term refers to nerves in the peripheral nervous system, while in the central nervous system this is referred as a nerve tract.