Autonomic Nervous System - General Arrangement
Autonomics Overview
Overview
- Parasympathetic preganglionic neurons lie within cranial nerve nuclei 3, 7, 9, 10 and the sacral intermediolateral cell column of the spinal cord, from S2 to S4, collectively called "craniosacral."
- Sympathetic preganglionic neurons lie within the thoracolumbar intermediolateral cell column, from T1 to L2: they lie in the between the cranial and sacral parasympathetic regions.
Pre- & Post-ganglionic fibers
Parasympathetic
- Postganglionic neurons lie far from the preganglionic neuron: in the wall of the target organ (or they lie close to the target organ, instead).
- Preganglionic parasympathetic axons travel a long distance to synapse on the postganglionic neuron.
- Postganglionic parasympathetic fibers project from the postganglionic neuron to deep into the target organ. They travel a short distance.
Sympathetic
- Postganglionic sympathetic neurons lie close to the preganglionic neurons (in the paravertebral chain or one of the prevertebral ganglia).
- Preganglionic sympathetic axons travels a short distance to synapse within the postganglionic neuron.
- Postganglionic sympathetic fibers travel a long distance to their target organ.