Cranial and sacral parasympathetic system

Sympathetic (red) and parasympathetic (green)

The cranial and sacral parasympathetic system is part of the parasympathetic autonomic nervous system. The system contains visceromotor and viscerosensitive fibers, provides perception of visceral pain and is an important afferent pathway for some reflexes (coughing, defecation, etc.). The mediator is acetylcholine. The parasympathetic runs upwards to the Cannon-Boehm point, where the innervation through the vagus nerve ends.

Cranial parasympathetic

Cores and functions

The parasympathetic nervous system in the head originates from several nuclei in the brainstem, mesencephalon, and rhombencephalon:

Nucleus oculomotorius accessorius

• (Edinger-Westphal) – parasympathetic nucleus of the oculomotor nerve
• stored in the midbrain
• preganglionic fibers of the ramus ad ganglion ciliare to the ganglion ciliare (Schacheri) via the ramus inferior nervi oculomotorii
• postganglionic fibers lead as nn. ciliares breves to the eyeball, where they innervate m. sphincter pupillae together with m. ciliaris
• Function: parasympathetic fibers cause miosis (narrowing) and accommodation of the lens for near vision, (sympathetic fibers cause mydriasis (dilation))
• ggl. ciliare also receives sensory fibers from the eyeball, which innervate the cornea

Nucleus salivatorius superior

• dorsal nucleus of the facial nerve located in the rhombencephalon in the center of the rhomboid fossa
• preganglionic parasympathetic fibers travel along the:

• pterygopalatine ganglion in the pterygopalatine fossa below the basis cranii externa

1. n. petrosus major, which reaches the pterygopalatine ganglion (Meckeli), here it connects and continues postganglionic through n. zygomaticus and by a junction to n. lacrimalis. It innervates the lacrimal glands, the mucous membrane of the nasal cavity and the mucous glands and vessels of the hard and soft palate.
2. n. petrosus profundus – sympathetic fibers from the internal carotid plexus join to form the n. canalis pterygoidei, which through the canalis pterygoidei leads to the pterygopalatine ganglion. Viscerosensitive taste fibers from the isthmus faucium also enter it, but they only pass through the ganglion and go to the n. facialis and through it to the ncl. tractus solitarii
3. chorda tympani, along with the parasympathetic nerve, also conducts sensory fibers of taste, enters the n. lingualis (branch of n. V) and the submandibulare ganglion, postganglionic innervation includes the sublingual and submandibular salivary glands

• submandibular ganglion – 2–3mm, at the upper edge of the submandibular gland under the lingual nerve, from the lingual nerve the ganglion branches to the rami ganglionares ad ganglion submandibulare

• function: parasympathetic stimulates secretion of mucous glands of the nasal cavity, palate, oral cavity and salivary glands (sublingual and submandibular)

Nucleus salivatorius inferior

• nucleus of the glossopharyngeal nerve in the brainstem under the base of the 4th ventricle at the interface between the medulla oblongata and the pons
• preganglionic fibers go in the tympani nerve passing through the middle ear cavity, receives sympathetic fibers from the nn. caroticotympanici, continues as the minor petrosal nerve to the otic ganglion (Arnoldi) at the mandibular nerve
• Postganglionic to n. auriculotemporalis for glandula parotis and to n. buccalis for facial glands of the mucous membrane
• otic ganglion - under the external basis of the skull at the foramen ovale, medial to the mandibular nerve from the trigeminal nerve
• function: stimulation of saliva secretion in the glands

Nucleus posterior nervi vagi

• vagus nucleus in the lower part of the rhomboid fossa
• preganglionic fibers run with the vagus nerve to the target organs, in whose walls they switch to postganglionic fibers

• includes rr. pharyngei, rr.cardiaci, rr. oesophagei, rr. tracheales, rr. bronchiales, rr. pulmonales, rr. gastrici, rr. coeliaci, rr. hepatici and rr. renales
• they go to the respiratory tract and lungs – n. laryngeus superior and reccurrens
• rr. coeliaci go together with the sympathetic in a mixed plexus around the vessels (plexus aorticus abdominalis, etc.)
• The vagus nerve and its parasympathetic fibers end at the level of the left flexure of the coccyx – the so-called Cannon-Boehm point, where the sacral parasympathetic nerve connects.
• separate parasympathetic fibers go to the heart – rr. cardiaci cervicales superiores et inferiores and rr. cardiaci thoracici, ending in the cardiac plexus

• Function: parasympathetically affects the activity of innervated organs, i.e. primarily increases the activity of the digestive tract and slows down cardiac activity. It also controls the viscerosensitivity of the heart and the beginning of the aorta, where it perceives the level of blood pressure through receptors

Sacral parasympathetic

Cores and plexuses

The sacral parasympathetic nuclei are located in the nucleus intermediolateralis S2–S4 - ncc. parasymphatici sacrales

The axons of the perikarya leave the spinal cord via the fila radicularia anteriora and, through the anterior roots, enter the sacral spinal nerves S2-S4. From there, preganglionic fibers send out as the sacral splanchnic nerves (sometimes incorrectly referred to as the erigentes or pelvic splanchnic nerves). These nerves go to the pelvic sympathetic plexuses, which are mixed from the upper part of the inferior hypogastric plexus.

Plexuses are formed around organs in the abdominal cavity and pelvis:

• plexus rectalis;
• plexus vesicalis;
• plexus deferentialis and plexus prostaticus – male;
• plexus uterovaginalis – female;
• nn. cavernosi penis/clitoridis – plexuses and nerves to the erectile tissues.

There are tiny pelvic ganglia in the braids that function as a switching point for the parasympathetic nervous system.

Function: increases intestinal motility, increases contraction of the bladder detrusor muscle and at the same time relaxes sphincters, increases urine production, induces vasodilation and filling of erectile bodies in the genitals.

Links

Related articles

• Sympathetic trunk
• Paraganglia

Used literature

• ČIHÁK, Radomír – GRIM, Miloš. Anatomie 3. 2., upr. a dopl edition. Grada, 2004. 673 pp. pp. 560. ISBN 80-247-1132-X.

• KACHLÍK, David. Autonomní nervy : Přednáška [online]. ©2012. [cit. 2012-02-01]. <http://old.lf3.cuni.cz/anatomie/Autonomninervy.zip>.