Facial nerve CN VII/Autonomic NS

Question 1

The motor branches of the facial nerve innervate what? What do they do?

Answer 1

1. Muscles of facial expression 2-3. posterior belly of digastic m, and stylohyoid (swallowing) 4. stapedius- noise reduction, smallest skeletal muscle in body. Disarticulates MIDDLE EAR bones.

Question 2

cells of origin for chorda tympani gustatory fibers?

Answer 2

geniculate ganglion, inside internal auditory meatus

Question 3

What are these branches of the facial nerve and where do they go?

Answer 3

a. Greater petrosal n.
b. Nerve to stapedius
c. chorda tympani n.
d. Main branch to the two suprahyoid mm.

Question 4

Name the nerves

Answer 4

see pic

Question 5

Sympathetic NS does what to blood to skin?

Answer 5

Less blood to skin.

Using beta-adrenergenic blockers, it lowers HR/contractility, which decreases O₂cardiac demand/ischemia.

Question 6

Where are the pre-ganglionic neurons in the sympathetic NS?

Answer 6

In the T1-L2 spinal cord

Question 7

Where are the pre-ganglionic neurons in the parasympathetic NS?

Answer 7

CN III, VII, IX, X, and lateral gray of S2-4 spinal cord.

Ones for Head: III, VII, IX

One for neck/thorax/most of abdomen: X

Question 8

What nerve gives over 75% of all pre-ganglionic parasympathetic fibers in the body?

Answer 8

Vagus n CN X

Question 9

Do cranial nerves give sympathetic or parasympathetic innervtation? Pre-ganglionic or post-ganglionic?

Answer 9

ONLY PRE-GANGLIONIC PARASYMPATHETIC!!! No other ANS innervation.

Question 10

What are the locations of the following, and what CN gives them their innervation, and what do they do?

1. Ciliary ganglion
2. Pterygopalatine ganglion
3. Submandibular gangion
4. Otic ganglion

Answer 10

1. CN III innervates: Ciliary ganglion is in the orbit. For pupilary constriction and ciliary muscle contraction.
2. CN VII innervates: Pterygopalatine ganglion is deep to the zygomatic bone/temporal process. For lacrimation and mucus in nose.
3. CN VII innervates: Submandibular ganglion is near the tongue. For salivation in the salivary glands.
4. CN IX innervates: Otic ganglion is deep to mandible and inferior to the zygomatic process. For salivation in the parotid gland.

Question 11

Does CN V have autonomic NS function?

Answer 11

NO

Question 12

the postganglionic fibers of the facial pre-ganglii travel with what?

Answer 12

1. CN III—Ciliary ganglion—post-ganglionic fibers traveling with/near V1
2. CN VII—Pterygo p. ganglion— post-ganglionic fibers traveling with/near branches of v2 and v1
3. CN IX—Otic ganglion—post-gangl. fibers traveling with/near v3
4. CN VII—submandibular gang—post gang. fibers traveling with/near v3

Question 13

Explain the parasympathetic pathway of lacrimation

Answer 13

From CN VII:

1. Pre-ganglionic fibers in the greater petrossal/pterygoid nn to the pterygopalatine ganglion.
2. Post-ganglionic fibers riding on v2 zygomatic br and communicating br go to orbit and then ride on v1 lacrimal n.
3. They then branch off of v1 to stimulate lacrimation by the lacrimal gland.

Question 14

Explain the parasympathetic pathway of nasal/oral mucus in face

Answer 14

CN VII

1. Pre-ganglionic fibers in greater petrossal/pterygoid nn go to the pterygopalatine ganglion
2. Post-ganglionic fibers riding on v2 nasopalatine and v2 greater/lesser palatine nn go to nasal and palatine glands to produce mucus.

Question 15

Explain the parasympathetic pathway of salivation from CN VII

Answer 15

1. Pre-ganglionic fibers in chorda tympani descend riding on travelling on v3 lingual n to the submandibular ganglion
2. Post-ganglionic fibers ride on v3 lingual n again to the submandibular and sublingual salivary glands.

Question 16

What fibers (pre or post, as well as symp/parasymp) make the deep petrossal and greater petrossal nerves? what happens to these nerves, what do they travel through, and where do they end up?

Answer 16

The greater petrossal nerve is parasympathetic pre-ganglionic fibers, and the deep petrossal nerve is sympathetic post-ganglionic fibers. They travel together (combine, as it looks) into the “pterygoid nerve” and travel to the pterygoid canal to get to the pterygopalatine ganglion in the pterygopalatine fossa.

Question 17

Is v2 above or below the pterygopalatine fossa? Where does it head next?

Answer 17

Above it. Heads for the infraorbital fissure.

Question 18

Name the numbered structures in the lacrimal pathway

Answer 18

1. v2 zygomatic branch
2. v2 zygomatic communicating branch
3. v1 lacrimal nerve
4. Pterygopalatine ganglion

Question 19

What is the thoracolumbar outflow? Where is it? Where does it go?

Answer 19

The axons of the sympathetic nervous system leaving the CNS, which happens at T1-L2. They form the sympathetic chain, extending from C1 to the sacrum.

Question 20

What are the two galglia that all sympathetics MUST synapse at before going to their target?

Answer 20

cervical chain ganglia or pre-aortic ganglia. Must go to one of them.

Question 21

What do the sympathetic fibers travel through in the spinal cord if going to the head or neck? Explain their pathway to their target.

Answer 21

Through the lateral horn. They then exit the thoracolumbar outflow ( mostly T1/2), which starts their pre-ganglionic fibers. They then reach the cervical chain ganglia, and then start their post-ganglionic fibers, which go to their target organ.

Question 22

What does the superior cervical ganglai send sympathetics to?

Answer 22

To the head, via carotids and branches.

Question 23

What does the middle cervical ganglion send sympathetics to?

Answer 23

To the heart and neck

Question 24

What does the inferior cervical ganglion send sympathetics to?

Answer 24

Heart (in addition to the middle ganglion), upper limbs, inferior neck, vertebral aa and other posterior cranial aa.

Question 25

Explain the sympathetics in the pterygoid canal. What nerve do they run with? Pre or post ganglionic?

Answer 25

sympathetics run on the deep petrossal nerve. the sympathetics are post-ganglionic, since they came off of their ganglia already. The parasympathetics are pre-ganglionic.

Question 27

Explain the parasympathetic pathway of CN III.

Answer 27

Visceromotor branch pre-ganglionics go to the ciliary ganglion, then post-ganglionically on v1 short ciliary, to the ciliary m.

Question 28

Explain the parasympathetic pathway of CN VII?

Answer 28

One branch: pre-ganglionics on the greater petrossal n goes to the pterygopalatine ganglion, the post ganglionics ride on v2 to the nasal and palatine glands, or on the v2 communicating branch to the lacrimal gland

Second branch: pre-ganglionics on the chorda tympani go to the submandibular gland, then ride on the v3 lingual branch to the sublingual or submandibular salivary glands.

Question 29

Explain the V3 magic number 1 2 stuff

Answer 29

4 sensory branches: BAIL

1. Lingual
2. Inferior alveolar
3. Articulotemporal
4. Buccal branch of V3

4 Masticator Motor Branches

1. Masseteric
2. n. to medial pterygoid
3. n. to lateral pterygoid
4. deep temporal (ant./post.)

4 Other Muscles

1. Mylohyoid
2. Ant. belly of digastic (First two from nerve to mylohyoid)
3. Tensor tympani
4. Tensor palatini

Question 30

On the way to its facial branches, the facial nerve exits the skull through what? What branches does it give off before the parotid gland? What does it do for the partotid gland? What does it then branch in to?

Answer 30

The stylomastoid foramen. Gives off posterior auricular and the n. to posterior digastric. Does sensory from parotid gland. Then branches in to the faciotemporal and cervico facial, which give off the:

Temporal

zygomatic

buccal br. of CN VII

marginal mandibular

cervical

Question 31

What nerve goes from the geniculate ganglion through the pterygoid canal? Where does it go?

Answer 31

The greater petrossal nerve. Travels to the pterygopalatine ganglion, Where it gives off post-ganglionics to the lacrimal gland and snot-making glands.