refers to a myelinated nerve fiber of the autonomic nervous system that transmits nerve impulses to a sympathetic chain. B fibers are approximately 2mm or less in diameter and carry impulses at speeds of 3-15 m/s. Compare with A fiber- C fiber.

B FIBER: "A B fiber transmits impulses from the autonomic nervous system to the sympathetic chain."
Cite this page: Nugent, Pam M.S., "B FIBER," in PsychologyDictionary.org, April 7, 2013, https://psychologydictionary.org/b-fiber/ (accessed June 28, 2017).