Acetylcholine Norepinephrine In the autonomic nervous system,<unk>  from the ganglion to the effector organ are called<unk><unk> .
Postganglionic nerve fibers
Preganglionic nerve fibers
Efferent nerve fiber
Special visceral afferent fiber
Parasympathetic nervous system
Muscle spindle
Secondary sensory endings
Special somatic afferent fiber