Parasympathetic Pathways of Head

Question 1

Which cranial nerves have parasympathetics? Which of these innervate glands or smooth muscle in the head?

Answer 1

CN III, VII, IX, and X all have parasympathetics, but only III, VII, and IX hit targets in the head. X distributes to a few visceral structures in the neck, but primarily those in the thorax, foregut and midgut.

Question 2

Name the parasympathetic terminal ganglia of the head. Which cell bodies reside in these?

Answer 2

Cilliary, pterygopalatine, submandibular, and otic.

Postganglionic cell bodies.

Question 3

What are the targets of parasympathetic nerves in the cilliary ganglion?

Answer 3

sphincter pupillae and cilliary muscle

Question 4

What are the targets of parasympathetic nerves in the pterygopalatine ganglion?

Answer 4

lacrimal gland and glands of the nasal cavity

Question 5

What are the targets of the parasympathetic nerves in the submandibular ganglion?

Answer 5

submandibular and lingual glands

Question 6

What are the targets of the parasympathetic nerves in the otic ganglion?

Answer 6

parotid gland

Question 7

Where do the parasympathetic preganglionics of CN III synapse?

Answer 7

cilliary ganglion

Question 8

How do the postganglionics of the occulomotor nerve reach their target? What is their target?

Answer 8

Their cell bodies reside in the cilliary ganglion, then they travel with the short cilliary nerves of CN V1 (opthalmic) to supply the constrictor pupillae and cilliary muscles of the eye (smooth muscle).

Question 9

Where do CN VII parasympathetic postganglionic cell bodies reside? What will they target?

Answer 9

Those that synapse with preganglionics from the chorda tympani will reside in the submandibular ganglion to target submandibular and sublingual glands.

Those that synapse with preganglionics from the greater petrosal branch and nerve of the pteryoid canal will reside in the pterygopalatine ganglion to target nasal mucous glands and lacrimal gland.

Question 10

How do parasympathetic postganglionics that target the nasal mucous and lacrimal glands reach their target?

Answer 10

From their cell bodies in the pterygopalatine ganglion, they will travel with the maxillary and opthalmic divisions of V (CN V1-2).
Specifically, for lacrimal gland, they will go from ganglion to zygomaticotemporal nerve (V2), then form a special autonomic branch, then join lacrimal nerve (V1) to hit gland.

Question 11

What nerve do parasympathetics traveling in the chorda tympani travel with?

Answer 11

lingual nerve (branch of CN V3)

Question 12

What do the parasymp preganglionics of CN IX travel?

Answer 12

They start in the motor nuclei in the brain and travel in the tympanic and lesser petrosal branches of CN IX to synapse in the otic ganglion, located in the roof of the infratemporal fossa.

Question 13

How to CN IX postganglionics reach their target? What is the target?

Answer 13

They from the otic ganglion with the auriculotemporal branch of mandibular nerve (CN V3) to the parotid gland

Question 14

Where do CN X parasymp postganglionics reside?

Answer 14

terminal ganglion near the target in the neck, thorax, and abdomen.

Question 15

What CN is the lesser petrosal nerve carrying parasympathetic fibers from?

Answer 15

CN IX preganglionics to the otic ganglion. Synapse then travel with auriculotemporal to hit parotid gland.

Question 16

What CN is the greater petrosal nerve carrying parasympathetic fibers from?

Answer 16

CN VII preganglionics to the pterygopalatine ganglion to synapse then travels with zygomatic, zygomatiicotemporal and lacrimal nerves to reach lacrimal gland and mucous glands of nose and palate.

Question 17

What does short cilliary nerve innervate? What type of fibers does it have?

Answer 17

GSA innervation of eyeball from CN V1.

CN III parasympathetic postganglionics travel with it to target sphincter pupillae.

Question 18

Where do the cell bodies of the sympathetic postganglionic neurons that run in the short cilliary nerve reside?

Answer 18

They pass through the cilliary ganglion, but do not synapse there. The preganglionics synapse in the superior cervical ganglion, so the postganglionic cell bodies are there, then they travel with the internal carotid (opthalmic artery) to the cilliary ganglion and on to innervate the dilator pupillae muscle

Question 19

How does CN VII leave the cranial cavity? How does it leave the skull?

Answer 19

CN VII passes into the internal acoustic meatus then leaves the skull through the stylomastoid foramen.

Question 20

What type of fibers does CN VII have as it enters the internal acoustic meatus?

Answer 20

GVE, GSA, SA, BE

Question 21

What type of fibers does CN VII have as it leaves the stylomastoid foramen?

Answer 21

BE and very small amount of GSA

Question 22

How does chorda tympani leave skull?

Answer 22

petrotympanic fissure

Question 23

Where is the geniculate ganglion and what nerve is associated with it? What cell bodies are located in it?

Answer 23

Located in the Genu of the bony canal of internal auditory meatus. Houses GSA and SA cell bodies.

Question 24

What two nerves come together to form nerve of the pterygoid canal and what do they carry?

Answer 24

Greater petrosal nerve carries GVE preganglionic parasymp.
Deep petrosal nerve carries sympanthetic postganglionics.

There is also SA returning from palate

Question 24

How does chorda tympani reach the petrotympanic fissure?

Answer 24

it leaves the bony canal and crosses the tympanic cavity, directly behind the eardrum

Question 25

Where are cell bodies of taste neurons in the chorda tympani located?

Answer 25

geniculate ganglion

Question 26

What type of fibers does CN IX carry and what are the targets of each?

Answer 26

Glossopharyngeal carries BE to stylopharyngeus.
GVE parasymp to parotid gland.
GSA to posterior tongue, palatine tonsils, oropharynx, mucosa of the middle ear and auditory tube.
GVA to carotid body and sinus
SA to posterior 1/3 of tongue and soft palate

Question 27

How does glossopharyngeal nerve exit the skull?

Answer 27

CN IX exits through Jugular foramen

Question 28

Describe the pathway of CN IX parasympathetics.

Answer 28

Preganglionic cell bodies in the brainstem, CN IX exits skull through jugular foramen then small branch (tympanic nerve) re-enters the bone then travels past the middle ear. It then exits the lesser petrosal hiatus as lesser petrosal nerve and travels in the groove in the middle cranial fossa to the foramen ovale to reach the otic ganglion. Synapses in otic ganglion then postganglionics travel with auriculotemporal nerve to parotid gland.

Question 29

Where are the majority of CN IX sensory cell bodies located?

Answer 29

Inferior ganglion

Question 30

What type of fibers does tympanic nerve carry?

Answer 30

GSA from tympanic membrane/auditory tube and GVE parasympathetic preganglionics.

Question 31

What happens in Frey’s syndrome?

Answer 31

Gustatory sweating caused by parasympathetics growing into severed sympathetics to sweat glands in skin above parotid gland.