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The neurotransmitters of postganglionic fibers differ: In the parasympathetic division , neurons are cholinergic . That is to say acetylcholine is the primary neurotransmitter responsible for the communication between neurons on the parasympathetic pathway .
There are two kinds of neurons involved in the transmission of any signal through the sympathetic system: pre-ganglionic and post-ganglionic. The shorter preganglionic neurons originate in the thoracolumbar division of the spinal cord specifically at T1 to L2~L3, and travel to a ganglion, often one of the paravertebral ganglia, where they synapse with a postganglionic neuron.
From here, the postganglionic sympathetic neuron can travel back out the grey ramus communicans of that level to the mixed spinal nerve and onto the effector organ. The preganglionic neuron can travel superiorly or inferiorly to a sympathetic paravertebral ganglion of a higher or lower level where it can synapse with a postganglionic ...
Electrical impulses carried by the sympathetic nervous system are converted to a chemical response in the adrenal gland. Chromaffin cells contained in the adrenal medulla act as postganglionic nerve fibers that release this chemical response into the blood as a circulating messenger. The sympathoadrenal system can activate and discharge ...
The nerve of the pterygoid canal contains axons of both sympathetic and parasympathetic axons, specifically; preganglonic parasympathetic axons from the greater petrosal nerve , a branch of the facial nerve (cell bodies are located in the superior salivatory nucleus )
The grey and white rami communicantes are responsible for conveying autonomic signals, specifically for the sympathetic nervous system. Their difference in colouration is caused by differences in myelination of the nerve fibres contained within, i.e. there are more myelinated than unmyelinated fibres in the white rami communicantes while the ...
Group C fibers include postganglionic fibers in the autonomic nervous system (ANS), and nerve fibers at the dorsal roots (IV fiber). These fibers carry sensory information. Damage or injury to nerve fibers causes neuropathic pain. Capsaicin activates C fibre vanilloid receptors, providing the burning sensation associated with chili peppers.
The SCG receives pre-ganglionic sympathetic afferents from the ciliospinal center which synapse in the ganglion. Post-ganglionic efferents then leave the SCG and join the internal carotid nerve plexus of the internal carotid artery, accompanying first this artery and subsequently its branches to reach the orbit and ultimately innervate the dilator pupillae muscle to mediate pupillary dilatation.