Preganglionic nerve fibers
| Preganglionic fibers | |
|---|---|
 Autonomic nervous system innervation, showing the sympathetic and parasympathetic (craniosacral) systems, in red and blue, respectively | |
| Details | |
| Identifiers | |
| Latin | neurofibrae preganglionicae |
| TA98 | A14.2.00.009 |
| FMA | 76568 |
| Anatomical terms of neuroanatomy | |
In the autonomic nervous system, fibers from the CNS to the ganglion are known as preganglionic fibers.
All preganglionic fibers, whether they are in the sympathetic division or in the parasympathetic division, are both cholinergic (that is, these fibers use acetylcholine as their neurotransmitter) and either unmyelinated or myelinated.
Sympathetic preganglionic fibers tend to be shorter than parasympathetic preganglionic fibers because sympathetic ganglia are often closer to the spinal cord than are the parasympathetic ganglia. Another major difference between the two ANS systems is divergence. Whereas in the parasympathetic division there is a divergence factor of roughly 1:4, in the sympathetic division there can be a divergence of up to 1:20. This is due to the number of synapses formed by the preganglionic fibers with ganglionic neurons.
In popular culture
In Star Trek: Deep Space Nine, Doctor Julian Bashir mistook a preganglionic fiber for a postganglionic nerve during the oral exam phase of his Starfleet Medical finals.[1]
See also
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References
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