Parasympathetic nervous system

Last revised by Calum Worsley on 30 Apr 2024

Citation, DOI, disclosures and article data

Citation:

Hacking C, Worsley C, Knipe H, Parasympathetic nervous system. Reference article, Radiopaedia.org (Accessed on 15 May 2024) https://doi.org/10.53347/rID-154401

DOI:

https://doi.org/10.53347/rID-154401

Permalink:

https://radiopaedia.org/articles/154401

rID:

154401

Article created:

12 Oct 2022, Craig Hacking ◉

Disclosures:

At the time the article was created Craig Hacking had the following disclosures:

Philips Australia, Paid speaker at Philips Spectral CT events (ongoing)

These were assessed during peer review and were determined to not be relevant to the changes that were made.

View Craig Hacking's current disclosures

Last revised:

30 Apr 2024, Calum Worsley ◉

Disclosures:

At the time the article was last revised Calum Worsley had no financial relationships to ineligible companies to disclose.

View Calum Worsley's current disclosures

Revisions:

11 times, by 3 contributors - see full revision history and disclosures

Systems:

Central Nervous System, Spine

Sections:

Anatomy

Synonyms:

PNS
PaNS
parasympathetic innervation

The parasympathetic nervous system (PaNS/PNS), mediated by the head and neck ganglia and pelvic splanchnic nerves, is a major division of the autonomic nervous system. It is composed of general visceral afferent and efferent axons that allow for involuntary control of bodily functions via several cranial nerve nuclei in the brainstem and the sacral segments of the spinal cord.

The overarching function of the parasympathetic system is to counteract the sympathoadrenal effects of the sympathetic nervous system.

The major neurotransmitter throughout the parasympathetic system is acetylcholine (ACh) ¹.

Gross anatomy

The cranial portion of the parasympathetic nervous system arises from four cranial nerve nuclei in the brainstem (see head and neck ganglia):

Edinger-Westphal nucleus in the midbrain contributes parasympathetic fibres to the oculomotor nerve that synapse at the ciliary ganglion; postganglionic fibres course in the short ciliary nerves to the ciliary body and sphincter pupillae, producing accommodation and pupillary constriction respectively
superior salivary nucleus in the pons contributes parasympathetic fibres to the facial nerve which synapse in the submandibular ganglion and pterygopalatine ganglion
- postganglionic fibres from the submandibular ganglion course with the nervus intermedius and then the chorda tympani of the facial nerve supplying secretomotor afferents to the sublingual and submandibular salivary glands
- postganglionic fibres from the pterygopalatine ganglion course with the greater superficial petrosal nerve of the facial nerve supplying secretomotor afferents to the lacrimal gland and mucosal glands in the nose, nasopharynx, sinuses and soft palate
inferior salivary nucleus in the pons contributes parasympathetic fibres to the glossopharyngeal nerve that synapse in the otic ganglion. Postganglionic fibres course with the auriculotemporal nerve (trigeminal mandibular division) supplying secretomotor afferents to the parotid gland
dorsal vagal nucleus in the medulla contributes parasympathetic fibres to the vagus nerve which synapse in the cardiac, renal, aorticorenal, coeliac, superior mesenteric, inferior mesenteric and superior hypogastric plexuses; postganglionic fibres distribute from these autonomic plexuses through the heart, oesophagus and lungs in the chest and most of the abdominal and pelvic viscera

The sacral portion of the parasympathetic nervous system arises from the grey matter of the sacral segments of the spinal cord at the level of S2–S4. These preganglionic fibres form the pelvic splanchnic nerves which synapse in the inferior hypogastric plexus. Some fibres pass through this plexus to the inferior mesenteric and superior hypogastric plexuses. Postganglionic fibres distribute through the structures of the hindgut and urogenital organs.