group b nerve fiber group b nerve fiber group b nerve fibers are axons, which are moderately myelinated, which means less myelinated than group a nerve fibers, and more myelinated than group c nerve fibers. their conduction velocity is 3 to 14 m/s. they are usually general visceral afferent fibers and preganglionic nerve fibers of the autonomic nervous system. they are used in bainbridge reflex as afferents. this article is issued from wikipedia. the text is licensed under creative commons - attribution - sharealike. additional terms may apply for the media files.