Midterm III: CNs X-XII (Ben)

Question 1

What 5 nuclei are associated with the vagus nerve (CN X)?

What kind fibers does each contribute to CN X?

Answer 1

1. Ambiguus - BM, SVM
2. Dorsal Vagal - GVM
3. Solitary - SVS
4. Lateral Ala Cinerea - GVS
5. Spinal Trigeminal - GSS

Question 2

What is the brain exit of CN X?

Dural exit?

Skull exit?

Answer 2

brain - lateral parolivary sulcus

dural - jugular foramen

skull - jugular foramen

Question 3

Where do the vagus nerve’s general visceromotor (parasympathetic) fibers originate?

And end?

Answer 3

Dorsal Vagal Nucleus (GVM)

End in:

• Meissner’s/Auerbach’s Plexuses - intramural ganglia of GI tract
• Prevertebral Ganglia - for thoracic organs

Question 4

Where do CN X’s branchiomotor (AKA special visceromotor) fibers originate?

Where do they synapse (generally)?

Answer 4

Nucleus Ambiguus

• synapse directly on target muscles… no ganglion

Question 5

Where do CN X’s general somatosensory fibers originate?

Where is their ganglion/cell body?

On what nucleus do they end?

Answer 5

Origin - Outer ear + Posterior Dura

Ganglion - Superior (Jugular) Ganglion of CN X

Termination - Spinal Trigeminal Tract

Question 6

Where do CN X’s special viscerosensory fibers originate?

What is their ganglion/cell body?

On what nucleus do they end?

Answer 6

Origin - Epiglottis Taste Buds

Ganglion - Inferior (Nodose) Ganglion of CN X

End - Solitary Nucleus

Question 7

On what nucleus do CN X’s general viscerosensory fibers terminate?

What is their ganglion/cell body?

Answer 7

Lateral Ala Cinerea

• Inferior (Nodose) Ganglion of CN X

Question 8

What organs receive general viscerosensory innervation from CN X?

Answer 8

• Lower Pharyngeal Mucosa
• Laryngeal Mucosa
• Baro-/Chemoreceptors of Aorta + Carotid
• Thoracic + Abdominal Viscera

Question 9

What are the 2 sensory ganglia of the vagus nerve near its exit from the skull?

What fiber types have their perikarya in these ganglia?

Answer 9

1. Superior (Jugular) Ganglion
   
   • ​​​​__GSS fibers
   • protopathic from posterior dura + external ear to spinal trigeminal nucleus
2. Inferior (Nodose) Ganglion
   
   • ​​SVS** + **GVS fibers
   • taste to solitary nucleus
   • visceral sensation to lateral ala cinerea

Question 10

What 2 branches does the vagus nerve give off to innervate structures of the head?

Answer 10

1. Meningeal Branch - posterior dura
2. Auricular Branch - external acoustic meatus + parts of pinna (joined by CN VII + IX)

Question 11

What 4 sets of branches does the vagus give off in the neck?

Answer 11

1. Pharyngeal Branches​​
2. Superior Laryngeal Nerve
3. Recurrent Laryngeal Nerve
4. Cardiac Branches
   
   • ​​Superior + Inferior Cervical Cardiac Branches

Question 12

What do the pharyngeal branches of the vagus innervate?

Answer 12

• Sensory - lower pharynx + epiglottis
• Taste - epiglottis
• Motor - soft palate + pharyngeal muscles​

Question 13

What specific muscles are innervated by pharyngeal branches of the vagus?

(maybe not so important for midterm III, but for semi-final)

Answer 13

• Lower 1/2 Middle Pharyngeal Constrictors
• Inferior Pharyngeal Constrictors
• Palatopharyngeus
• Salpingopharyngeus
• Palatoglossus
• Levator Veli Palatini

MC.IC.Pp.Sp.Pg.LVP

Question 14

What are the 2 branches of the superior laryngeal nerve (and their innervated organs)?

Answer 14

1. Internal Laryngeal Nerve
   
   • mucus membrane of larynx above vocal folds
2. External Laryngeal Nerve
   
   • cricothyroid muscle

Question 15

What are the 3 branches of the recurrent laryngeal nerve?

(What do they innervate?)

Answer 15

1. Esophageal Branches
2. Tracheal Branches
3. Inferior Laryngeal Nerve
   
   • mucosa of larynx below vocal fold
   • all laryngeal muscles except cricothyroid

Question 16

What are the 3 important sets of thoracic branches of the vagus?

Answer 16

1. Thoracic Cardiac Branches
2. Esophageal Branches
3. Pulmonary Branches

Question 17

How do the positions of the vagal nerves change as they descend along the “rotated” stomach?

Answer 17

Anterior Vagal Trunk - comes from left vagus

Posterior Vagal Trunk - comes from right vagus

Question 18

What are the important 4 abdominal branches/groups of nerves coming from the vagal trunks?

Answer 18

1. Gastric Branches
2. Celiac Branches - celiac plexus
3. Hepatic/Pyloric/Gall Bladder Branches - hepatic plexus in lesser omentum
4. Nerves for Small and Large Intestines - up to left colic flexure

Question 19

What are the 2 nuclei associated with the accessory nerve?

What type of nuclei are they?

Answer 19

1. Nucleus Ambiguus - BM
2. Spinal Accessory Nucleus - SM

Question 20

Where is the spinal accessory nucleus of the accessory nerve?

Answer 20

in the lateral anterior horn of the spinal cord from C1-C5

Question 21

What are the two roots of the accessory nerve?

Where do they unite?

Where do they separate?

Answer 21

1. Cranial Root
2. Spinal Root

• unite in the posterior cranial fossa
• separate upon entering the jugular foramen

Question 22

What does the spinal root of the accessory nerve innervate?

Answer 22

1. Sternocleidomastoid
2. Trapezius

Question 23

What does the cranial root of the accessory nerve innervate?

Answer 23

Via joining the vagus nerve…

1. All laryngeal muscles except cricothyroid
2. Pharyngeal muscles

Question 24

What is the nucleus of CN XII?

What type of nucleus is it?

Where is it?

Answer 24

Hypoglossal Nucleus

• somatomotor
• in the hypoglossal trigone of the medulla

Question 25

What does the hypoglossal nerve innervate?

Two things it innervates are supplied by a special nerve structure to which CN XII contributes.

What is this structure?

Answer 25

• Intrinsic Muscles of the Tongue
• Extrinsic Muscles of the Tongue (except palatoglossus)
• Geniohyoid + Thyrohyoid
  
  • via deep cervical ansa