Cranial Nerves Flashcards
What are special sensory fibers?
carry information to the brain about smell, vision, taste, hearing or balance
What are Somatic (general) sensory fibers?
touch, pain, temp, pressure, vibration and proprioception
Visceral sensory fibers carry information about?
distension and pain from viscera, blood vessels etc
Branchial motor fibers innervate?
skeletal muscles derived from branchial arches
Somatic motor fibers innervate?
skeletal muscles derived from somites
Visceral motor fibers innervates?
smooth muscle, cardiac muscle and glands
Name the sensory ganglia of CNs?
trigeminal ganglion (V), geniculate ganglion (VII) spiral and vestibular ganglia (VIII), Superior and inferior ganglia of (IX) Superior and inferior ganglia of (X)
Define sensory ganglion:
swellings along the course of a cranial nerve that contain cell bodies of sensory neurons
no synapses
pseudopolar neurons collect information from head and neck and sends it to the sensory ganglion -> brainstem
Define Parasympathetic ganglia
visceral motor ganglia
all parasympathetic
preganglionic fibers synapse with postganglionic parasympathetic neurons, then they innervate smooth muscle, cardiac muscle, glands
What are the Parasympathetic ganglia of CNs?
ciliary ganglion (III), submandibular and pterygopalatine ganglia (VII), otic ganglion (IX), intramural (terminal) ganglion (X)
CN 1 Name Ganglia Fiber type Route
Olfactory nerve
no ganglia
SS - smell
Route: cribiform plate of ethmoid bone to olfactory bulb of anterior cranial fossa and synapses with secondary sensory neurons in the olfactory tract
CN 2 Name Ganglia Fiber type Route
optic nerve
no ganglia
SS - vision (and reflexes)
Route: exits through optic canal to optic chiasm, Fibers decussate such that nasal fibers from the contalateral eye and temporal fibers from the ipsilateral eye unite as the optic tract and extend to the brain.
Note: CN II is an actual extension of the brain
CN 3 Name Ganglia Fiber type Route
Occulomotor Nerve
SM
VM - parasympathetic root of ciliary ganglion
Route: brainsteim->exits middle crainal fossa via superior orbital fissue,then splits to inferior and superior divisions
What do the different divisions of the SM fibers of CN III innervate?
Superior: levator palpebrae superiororis muscles and superior rectus muscle
Inferior: medial rectus m. inferior rectus and inferior oblique m.
:describe parasympathetics of III
Presynaptic parasympathetics from preganglionic parasympathetic neurons in the brainstem follow the inferior division of CN III and depart as the parasympathetic root of the ciliary ganglion. Here they synapse with postganglionic parasympathetic neurons whose fibers reach the eye via short ciliary nerves and innervate smooth muscle fibers of the constrictor pupillae (to constrict the pupil) and ciliary muscle (to thicken the lens)
CN 4 Name Ganglia Fiber type Route Innervation
Trochlear Nerve:
no ganglia
SM
Route: arise from neurons in the brainstem. ->exits the middle cranial fossa via the superior orbital fissure and enters the bony orbit
Innervates: superior oblique muscle of the eye.
CN 5 Name Ganglia Fiber type Route
Trigeminal Nerve:
1 sensory ganglion, the trigeminal
GS, BM fibers.
Route: trifurcates:
V1: ophthalmic (CN V1) nerve which exits the middle cranial fossa via the superior orbital fissure
V2 Maxillary nerve (CN V2) that passes through the foramen rotundum,
V3: mandibular nerve (CN V3) that traverses the foramen ovale.
CN 6 Name Ganglia Fiber type Route Innervation:
Abducens Nerve:
no ganglia
SM fibers from brainstem.
Route: exits the middle cranial fossa via the superior orbital fissure and enters the bony
orbit
Innervates: lateral rectus muscle of the eye.
CN 7 Name Ganglia Fiber type Route Innervation:
Facial Nerve:
two motor ganglia: pterygopalatine and submandibular
one sensory ganglion: the geniculate.
Fibers: Motor root carries: BM (Nervous intermedius carries: VM (preganglionic parasympathetics), GS and SS (10 branches).
Route: brainstem as a motor root and a mixed-function root (nervous intermedius), both exit the posterior cranial fossa via the internal acoustic
meatus (motor root is superior to the nervous intermedius). -> facial canal, a tunnel in the petrous temporal bone, and unite -> geniculate ganglion and produces the greater petrosal nerve ->
then passes posterior to the middle ear where it produces the stapedius nerve and chorda tympani. Next, it sends a branch to the auricular nerve (branch of CN X) and then exits the stylomastoid foramen where it sequentially produces
the posterior auricular nerve and stylohyoid nerve and then passes through the parotid gland. It terminates by dividing into temporal, zygomatic, buccal, (marginal) mandibular and cervical nerves.
Name origin/route of greater petrosal nerve/what does it do?
What kind of fibers is it?
CN VII: Brainstem as a motor root and a mixed-function root (nervous intermedius), both exit the posterior cranial fossa via the internal acoustic
meatus (motor root is superior to the nervous intermedius). -> facial canal, a tunnel in the petrous temporal bone, and unite -> geniculate ganglion and produces the greater petrosal nerve -> presynaptic fibers crosses the floor of the middle cranial fossa, enters the pterygoid canal and join sympathetic fibers -> reaches the pterygopalatine ganglion in the pterygopalatine fossa. Then presynaptic fibers synapse with postsynaptic neurons.
Postsynaptic fibers hitchhike on branches of CN V to innervate the lacrimal gland and glands of the paranasal sinuses, nasal cavity, hard and soft palates and associate gingival. Cause gland secretion.
Visceral Motor (parasympathetic) fibers. Special Sensory fibers: Palatine fibers follow the palatine nerves (branches of CN V), pterygopalatine ganglion, nerve of the pterygoid canal and greater petrosal nerve to the geniculate ganglion. Central processes follow the nervous intermedius to the brainstem.
Name origin/route of corda tympani/what does it do?
Route: brainstem as a motor root and a mixed-function root (nervous intermedius), both exit the posterior cranial fossa via the internal acoustic
meatus (motor root is superior to the nervous intermedius). -> facial canal, a tunnel in the petrous temporal bone, and unite -> geniculate ganglion and produces the greater petrosal nerve ->
then passes posterior to the middle ear where it produces the stapedius nerve and chorda tympani. Crosses the tympanic cavity, joins the lingual nerve (branch of CN V) to the submandibular
ganglion where presynaptic fibers synapse with postsynaptic neurons. Postsynaptic fibers follow blood vessels to innervate submandibular and
sublingual salivary glands and minor salivary glands in the floor of the mouth and adjacent gingiva.
Cause gland secretion.
Also has SS fibers: 2/3 taste for anterior of the tongue and soft palate
.
What does the branchial motor fibers of CN VII do?
Form the motor root of the facial nerve.
Routes:
Follow facial nerve and form the stapedius nerve that innervates this muscle
Follow the auricular nerve that innervates posterior auricular and occipitalis muscles.
Follow the stylohoid nerve to innervate stylohyoid and posterior belly of the digastric muscles. Follow temporal, zygomatic, buccal, marginal mandibular and cervical branches to innervate
the many muscles of facial expression.
What does the somatic sensory fibers of CN VII do? (Don’t get this)
Peripheral processes of somatic sensory neurons in the geniculate ganglion innervate the external ear. Fibers follow the auricular nerve (branch of CN X) and then the facial nerve to the geniculate ganglion. Central processes follow the nervous intermedius to the brainstem.
What does the SS fibers of CN VII do/what are the routes?
Special Sensory: Peripheral processes of special sensory neurons in the geniculate ganglion innervate taste buds in the anterior 2/3 of the tongue and the soft palate via two different routes. Tongue fibers follow the lingual nerve (branch of CN V) and chorda tympani to the geniculate ganglion. Palatine
fibers follow the palatine nerves (branches of CN V), pterygopalatine ganglion, nerve of the pterygoid canal and greater petrosal nerve to the geniculate ganglion. Central processes follow the nervous intermedius to the brainstem.
CN 8 Name Ganglia Fiber type Route Innervation:
Vestibulocochlear Nerve: Th
two sensory ganglia, the vestibular and cochlear
Fibers: Special sensory
Route: two divisions, vestibular and cochlear
Nerve rises in the brainstem, exits the posterior cranial fossa via the internal acoustic meatus (inferior to nervous intermedius of CN VII) and traverses the petrous temporal bone where it divides and distributes to membranous structures of the inner ear.
Describe the vestibular divison of CN VIII:
For balance.
Formed of central processes from special sensory neurons within the vestibular ganglion. Peripheral processes innervate the inner ear and detect position and movement of the head relating to balance (see Ear Lecture). Central processes form the vestibular division that joins the cochlear division to form CN VIII.
Describe the cochlear divison of CN VIII:
For hearing:
Formed of central processes from special sensory neurons located in the spiral ganglion of the cochlea. Peripheral processes innervate the spiral organ (of Corti) of the inner ear and perceive sound waves relating to hearing (see Ear Lecture). Central processes form the cochlear to CN VIII.
CN 9 Name Ganglia/locations Fiber type Route Innervation:
Glossopharyngeal Nerve:
Ganglia: one motor ganglion, Sensory: otic, superior and inferior sensory ganglia.
Fibers: BM, VM, VS, GS, SS; 7 branches.
Otic ganglion is the site of synapse between presynaptic parasympathetic fibers and postsynaptic parasympathetic neurons; it lies deeply in the infratemporal fossa.
Sensory ganglia house neurons whose peripheral processes detect general, visceral and special sensations. Superior sensory ganglion lies in the jugular foramen and the inferior ganglion just below.
CN IX arises from the brainstem and exits the posterior cranial fossa via the jugular foramen and anterior to CN X. Near or in the jugular foramen, it gives off the tympanic nerve and a branch to the auricular nerve (branch of CN X). Then produces stylopharyngeus, pharyngeal, tonsillar, lingual and carotid nerves.
IX: SS
Ganglia: inferior
Function: taste for posterior 1/3 of tongue
Route follow the lingual branch
Special Sensory Fibers: Peripheral processes of special sensory neurons in superior and inferior ganglia innervate the posterior 1/3 of tongue for taste. Peripheral processes follow the lingual branch to reach the ganglia and central processes project to the brainstem.
XI: GS
Ganglia: Inferior and Superior
Function: posterior 1/3 of tongue, inner surface of tympanic membrane, tympanic cavity, auditory tube, pharynx
Somatic Sensory Fibers: Peripheral processes of somatic sensory neurons in superior and inferior ganglia innervate the external ear by a twig to the auricular nerve (branch of CN X). Other peripheral processes innervate the middle ear, inner tympanic membrane and pharyngotympanic (eustachian) tube; these converge at the tympanic plexus and follow the tympanic nerve to the glossopharyngeal ganglia. Finally, peripheral processes innervate the oral cavity (includes gag reflex), tonsillar bed and posterior 1/3 of the tongue
via pharyngeal, tonsillar and lingual nerves, respectively. Peripheral processes reach the ganglia and central processes project to the brainstem.
NOTE: COA assigns visceral sensory fibers to the pharynx, but this is probably incorrect because these fibers convey information about
temperature – a somatic sensory sensation.
XI: VS
Ganglia: inferior
Function: carotid body and sinus
Visceral Sensory Fibers: Peripheral processes of visceral sensory neurons in the superior and inferior ganglia reach the carotid body and sinus via the
carotid nerve. Fibers form chemoreceptors in the carotid body that monitor oxygen tension in circulating blood and baroreceptors in the carotid sinus that monitor arterial blood pressure. Peripheral processes reach the ganglia and central processes project to the brainstem.
XI: BM
Ganglia: none
Function: stylopharyngeus
Branchial Motor Fibers: Branchial motor fibers form the stylopharyngeus nerve and innervate this muscle.
XI: VM
Ganglia: otic
Function: parasympathetics to parotid gland
Visceral Motor (Parasympathetic) Fibers: Presynaptic parasympathetic fibers exit in the tympanic nerve and pursue a tortuous route. Fibers traverse the tympanic plexus of the middle ear, exit as the lesser petrosal nerve, cross the floor of the middle cranial fossa, pass through the foramen oval (or near it) and synapse with postsynaptic parasympathetic neurons in the otic ganglion. Postsynaptic fibers join the auriculotemporal nerve (branch of CN V) to the parotid gland and cause secretion.
CN 10 Name Ganglia/locations Fiber type Route Innervation:
Vagus Nerve, CN X:
Ganglion: superior and inferior
sensory ganglia and many terminal or intramural motor ganglia. Fibers: BM, parasympathetic (ie VM), VS, GS, SS; 6 or 7 branches
The superior ganglion lies in the jugular foramen and the inferior (nodose) ganglion lies below it.
Route: brainstem -> jugular foramen anterior to CN XI. Produces meningeal and auricular nerves. Pharyngeal, carotid, superior laryngeal, right recurrent laryngeal and cardiac nerves arise in the neck: the left recurrent laryngeal nerve arises in the thorax. Thoracic and abdominal nerves were covered in Block II.
X: SS
Ganglia: inferior (nodose)
Function: taste for region around epiglottis
Route: internal laryngeal branch of superior laryngeal nerve
Special Sensory Fibers: Peripheral processes of special sensory neurons in the vagal ganglia innervate the base of the tongue and epiglottis for taste via the internal laryngeal branch of the superior laryngeal nerve. Peripheral processes pass to the vagal ganglia and central processes project to the brainstem. The meningeal nerve of the vagus distributes C2 general sensory fibers to the meninges (see Meninges lecture).
X: GS
Ganglia: Superior
Function: auricle of ear, external acoustic meatus, outer surface of tympanic membrane, pharynx
Route: auricular nerve, pharyngeal nerve and plexus and by the internal laryngeal branch of the superior laryngeal nerve.
Somatic Sensory Fibers: Peripheral processes of somatic sensory neurons in the vagal ganglia innervate the external ear (see Ear Lecture) via the auricular nerve of the vagus. The lower pharynx receives somatic sensory fibers via the pharyngeal nerve and plexus and by the internal laryngeal branch of the superior laryngeal nerve. Peripheral processes pass to the vagal ganglia and central processes project to the brainstem. NOTE: Again, COA considers lower pharynx to receive visceral sensory fibers (see above).
X: VS
Ganglia: inferior (nodose)
Function: aortic body and arch, larynx, esophagus and viscera (carotid body and sinus)
Route: internal laryngeal branch of the superior laryngeal nerve, recurrent laryngeal nerve, a twig to the carotid nerve
Visceral Sensory Fibers: Peripheral processes of visceral sensory neurons in the vagal ganglia innervate the larynx and upper esophagus. Fibers to the larynx follow the internal laryngeal branch of the superior laryngeal nerve. Fibers to the upper pharynx follow the recurrent laryngeal nerve. Fibers also contribute to baroreceptors in the carotid sinus and chemoreceptors in the carotid body via a twig to the carotid nerve (branch of CN IX). Peripheral processes pass to the ganglia and central processes project to the brainstem.
X: BM
Ganglia: none
Function: muscles of pharynx (except stylopharyngeus), muscles of palate (except tensor veli palatini), muscles of the larynx, palatoglossus (palate and tongue muscles)
Branches: pharyngeal plexus, superior laryngeal nerve and its external laryngeal branc, recurrent laryngeal nerve
Branchial Motor Fibers: Branchial motor fibers of the vagus arise from brainstem; most briefly join the accessory nerve (CN XI) before merging with
the vagus. Branchial motor fibers innervate the following skeletal muscles: the pharyngeal nerve via the pharyngeal plexus innervates all pharyngeal muscles except the stylopharyngeus (CN IX) and part of the inferior constrictor; all palate muscles except the tensor veli palatini (CN V); and one extrinsic tongue-palate muscle, the palatoglossus. Other fibers follow the superior laryngeal nerve and its external laryngeal branch to supply part of the inferior pharyngeal constrictor and the cricothyroideus muscle. Lastly, fibers follow the recurrent laryngeal nerve to innervate the remaining laryngeal muscles (see Larynx lecture) and upper esophagus.
X: VM
Ganglia: terminal (intermural)
Function: parasympathetics to pharynx, larynx and viscera as far left as colic flexure
Route: pharyngeal nerve and plexus, internal laryngeal nerve, a branch of superior laryngeal, recurrent laryngeal nerve
Visceral Motor (Parasympathetic) Fibers: Presynaptic parasympathetic fibers synapse in intramural (terminal) ganglia in or near the wall of organs. In the head and neck, presynaptic fibers are distributed to glands of the pharynx via the pharyngeal nerve and plexus, to glands of the larynx by the internal laryngeal nerve, a branch of superior laryngeal, and to glands of the larynx and upper esophagus by the recurrent laryngeal nerve.
CN 11 Name Ganglia/locations Fiber type Route Innervation:
Accessory Nerve
Ganglia: none
Fiber: BM, SM
unusual cranial nerve.
two roots: a cranial root arising from the
brainstem and a spinal root from the spinal cord. Route:
Cranial root arises from the brainstem, briefly joins the spinal root and then separates. It then joins and provides branchial motor fibers to the vagus.
Function: delivered to CNX to muscles of pharynx, palate, larynx, on tongue muscle
Spinal root forms from C1-C5 segments of
the spinal cord and carries somatic motor fibers; it ascends through the foramen
magnum, briefly joins the cranial root and exits the cranium via the jugular foramen. The spinal root descends through the neck and innervates sternocleidomastoid and trapezius muscles.
Modern descriptions assign the branchial motor fibers to the vagus nerve and somatic motor fibers to the accessory nerve.
CN 12 Name Ganglia/locations Fiber type Route Innervation
Hypoglossal Nerve, CN XII:
Fibers: SM
Route: brainstem -> cranium via the hypoglossal canal -> passes lateral to the bifurcation of the common carotid artery, loops anteriorly and
above the greater cornu of the hyoid bone and passes behind the free posterior border of the mylohyoid muscle to reach the tongue. Fibers from the anterior rami of C1 and C2 spinal nerves hitchhike with the hypoglossal nerve.
Innervates: (all extrinsic and intrinsic tongue muscles except the palatoglossus (CN X))
Semilunar ganglia: Type Cranial Nerve Fiber Types Synapse
Semilunar Sensory CN V Somatic sensory No*
Type
Cranial Nerve
Fiber Types
Synapse
Geniculate Sensory CN VII Somatic sensory
Special sensory
No*
Type
Cranial Nerve
Fiber Types
Synapse
Spiral Sensory CN VIII Special sensory No*
Type
Cranial Nerve
Fiber Types
Synapse
Vestibular Sensory CN VIII Special sensory No*
Inferior & superior Type Cranial Nerve Fiber Types Synapse
- Sensory
- CN IX
- Somatic sensory, Special sensory, Visceral sensory
- No*
Ciliary Type Cranial Nerve Fiber Types Synapse
- Motor
- CN III
- Visceral motor
- Yes*
Pterygopalatine Type Cranial Nerve Fiber Types Synapse
- Motor
- CN VII
- Visceral motor
- Yes*
Submandibular Type Cranial Nerve Fiber Types Synapse
Motor
CN VII
Visceral motor
Yes*
Intramural (in wall of organ) Type Cranial Nerve Fiber Types Synapse
Motor
CN X
Visceral motor
Yes*
Otic Type Cranial Nerve Fiber Types Synapse
Motor
CN IX
Visceral motor
Yes*
Do sensory ganglia contian synapses?
no
Do autonomic ganglia contain synapses?
yes
PALATE: 5 pair of muscles to soft palate (branchial motor)/innervations by:
Tensor veli palatini (tensor palati) V3 Levator veli palatini (levator palati) X* Musculus uvulae (didn’t cover) X* Palatopharyngeus X* Palatoglossus X*
PHARYNX: 6 pair of pharyngeal muscles (branchial motor) / innervations by
3 circular: Superior constrictor X* Middle constrictor X* Inferior constrictor X* & external laryngeal 3 longitudinal: Palatopharyngeus X* Salpingopharyngeus X* Stylopharyngeus IX
LARYNX: (branchial motor)/innervations by
LARYNX: (branchial motor)
Posterior cricoarytenoid X via recurrent laryngeal
Lateral cricoarytenoid X via recurrent laryngeal
Vocalis X via recurrent laryngeal
Arytenoid X via recurrent laryngeal
Thyroarytenoid X via recurrent laryngeal
Cricothyroid X via external laryngeal
TONGUE: (somatic motor)/innervation by
4 extrinsic muscles Palatoglossus X* Styloglossus XII Hyoglossus XII Genioglossus XII 4 intrinsic muscles Superior longitudinal XII Inferior longitudinal XII Vertical XII Transverse XII
SUPRAHYOID MUSCLES: (branchial motor except for geniohyoid)/ innervations
Geniohyoid C1 (hitchhikes on XII) Stylohyoid VII Posterior belly of digastric VII Anterior belly of digastric n. to mylohyoid (V3) Mylohyoid n. to mylohyoid (V3)
INFRAHYOID MUSCLES + innervated by:
(somatic motor)
Superior & inferior belly of omohyoid Ansa cervicalis (C1,C2,C3)
Sternohyoid Ansa cervicalis (C1,C2,C3)
Sternothyroid Ansa cervicalis (C1,C2,C3)
Thyrohyoid C1 (hitchhikes on XII)
STYLOID MUSCLES: + innervated by:
(branchial motor except for styloglossus)
Stylohyoid VII
Stylopharyngeus IX
Styloglossus XII
MUSCLES OF MASTICATION + innervated by
(branchial motor) Lateral pterygoid V3 Medial pterygoid V3 Temporalis V3 Masseter V#
SENSATION + innervated by:
General sensation to posterior 1/3 of tongue IX
General sensation to anterior 2/3 of tongue V3 via lingual nerve
General sensation to superior nasopharynx V2
General sensation to inferior nasopharynx IX
General sensation to oropharynx IX (overlaps with X)
Visceral sensation to laryngopharynx & larynx X (Overlaps with IX)
Visceral sensation superior to vocal folds X via internal laryngeal nerve
Visceral sensation inferior to vocal folds X via recurrent laryngeal nerve
TASTE + innervated by:
Palate VII ** (nervous intermedius)
Anterior 2/3 of tongue VII (nervous intermedius)
Posterior 1/3 of tongue IX
Base of tongue & epiglottis X
VISCERAL MOTOR FIBERS (PARASYMPATHETICS):
1. To sphincter pupillae & ciliary muscle
Preganglionic parasympathetic fibers from CN III inferior division of CN III parasympathetic root of ciliary ganglion synapse in ciliary ganglion
postganglionic parasympathetic fibers to short ciliary nerves eyeball contract ciliary muscle and sphincter pupillae muscle.
VISCERAL MOTOR FIBERS (PARASYMPATHETICS):
To lacrimal gland:
Preganglionic parasympathetic fibers from
nervous intermedius of CN VII greater petrosal nerve nerve of
pterygoid canal synapse in pterygopalatine ganglion postganglionic
parasympathetic fibers follow CN V2 zygomatic nerve zygomaticotemporal
nerve lacrimal nerve lacrimal gland.
VISCERAL MOTOR FIBERS (PARASYMPATHETICS): To mucous glands of nasal cavity and paranasal sinuses:
Preganglionic parasympathetic fibers from nervous intermedius
of CN VII greater petrosal nerve nerve of pterygoid canal synapse in
pterygopalatine ganglion postganglionic parasympathetic fibers to lateral and
septal nasal nerves mucous glands of nasal cavities and paranasal sinuses.
VISCERAL MOTOR FIBERS (PARASYMPATHETICS): To minor salivary glands of palate and upper oral mucosa:
Preganglionic parasympathetic fibers from nervous intermedius
of CN VII greater petrosal nerve nerve of pterygoid canal synapse in
pterygopalatine ganglion postganglionic parasympathetic fibers to lesser (and
greater) palatine nerves minor salivary glands of palate and upper oral mucosa.
VISCERAL MOTOR FIBERS (PARASYMPATHETICS): To submandibular gland, sublingual gland and minor salivary
glands of floor of mouth:
Preganglionic parasympathetic fibers
from nervous intermedius of CN VII chorda tympani lingual nerve synapse in submandibular ganglion postganglionic parasympathetic fibers follow blood vessels to submandibular and sublingual glands and minor salivary glands in
floor of mouth.
VISCERAL MOTOR FIBERS (PARASYMPATHETICS): To parotid gland:
Preganglionic parasympathetic fibers from CN
IX tympanic nerve (of Jacobson) tympanic plexus lesser petrosal nerve synapse in otic ganglion postganglionic parasympathetic fibers to
auriculotemporal nerve parotid gland.
VISCERAL MOTOR FIBERS (PARASYMPATHETICS): To mucous glands of pharynx and larynx:
Preganglionic parasympathetics from CN X pharyngeal plexus synapse in intramural
ganglia of pharyngeal mucosa postganglionic parasympathetics to pharyngeal mucous glands OR Preganglionic parasympathetics from CN X internal laryngeal nerve & recurrent laryngeal nerve synapse in intramural ganglia of laryngeal
mucosa postganglionic parasympathetics to laryngeal mucous glands.
VISCERAL MOTOR FIBERS (SYMPATHETICS):
Preganglionic sympathetics from upper thoracic levels synapse in superior cervical
ganglion. Postganglionic sympathetics: 1) Follow external carotid arteries to innervate
arrector pili muscles, sweat glands and blood vessels of skin; 2) Follow internal carotid
artery to ophthalmic artery to innervate superior tarsal muscle of eyelid; 3) Follow long
ciliary and short ciliary nerves to reach dilator pupillae muscle and blood vessels of
eyeball.
