Lecture 21 - Parasympathetic Cranial Nerves

Question 1

What is the modality, function, and path of CN III?

L21 S7

Answer 1

Oculomotor nerve

Modality:

• general somatic motor (GSM)
• general visceral motor (GVM)

Function:

• innervates 4/6 extrinsic muscle of eye and levator palpebrae superioris (GSM)
• innervates constrictor pupillae and ciliary muscles (GVM)

Path:

• from Oculomotor complex (GSM) or Edinger-Westphal nucleus (GVM)
• through superior orbital fissure
• to muscles (GSM) or ciliary ganglion (GVM)

Question 2

Describe the major branches of CN V and what they do.

L21 S10-11

Answer 2

Ophthalmic (V-1):

• exits superior orbital fissure
• sensation of orbit and contents
• sensation of nose and skin above eye
• branches: frontal, lacrimal, and nasociliary

Maxillary (V-2):

• exits through foramen rotundum
• sensation of maxillary region
• branches: infraorbital, ant. sup. alveolar, zygomatic, palatine, nasal, and post. sup. alveolar

Mandibular (V-3):

• exits through foramen ovale
• sensation of mandibular region
• branches: muscles of mastication, auriculotemporal, inferior alveolar, lingual, buccal

Question 3

What are the modalities of the trigeminal nerve?
What special relationship does it have with another cranial nerve?

L21 S12

Answer 3

General somatic sensory (GSS):
-sensation of face and tongue (not taste)

Special visceral motor (SVM):
-innervation of muscles of mastication (derived from first pharyngeal arch)

CN V runs with parasympathetic branches of CN VII (facial)

Question 4

What are the modalities of the the CN VII?

L21 S18

Answer 4

Facial nerve

Special visceral motor (SVM):
-supplies muscles of facial expression (derived from second pharyngeal arch)

General somatic sensory (GSS):
-sensation of external ear

Special visceral sensory (SVS):
-sensation of taste from anterior 2/3 of tongue

General visceral motor (GVM):
-supplies several glands

Question 5

Describe the SVM modality of CN VII.

L21 S19

Answer 5

Path:

• from motor nucleus of CN VII
• exits through stylomastoid foramen

Function:

• supplies muscles through temporal, zygomatic, buccal, mandibular, and cervical branches
• supplies stapedius, stylohyoideus, and posterior digastric

Question 6

Describe the GSS modality of CN VII.

L21 S20

Answer 6

Path:
-cell bodies in geniculate nucleus

Function:
-sensation of external ear

Question 7

Describe the SVS modality of CN VII.

L21 S21

Answer 7

Path:

• primary cell bodies in geniculate nucleus
• secondary neurons in solitary nucleus
• tertiary neurons end in thalamus

Function:

• sensation of taste in anterior 2/3 of tongue
• sensation of tastes in hard and soft palate

Question 8

Describe the GVM modality of CN VII.

L21 S22

Answer 8

Path:

• from superior salivatory nucleus or lacrimal nucleus (preganglionic)
• submandibular or pterygopalatine ganglia (postganglionic)

Function:

• supply of lacrimal glands
• supply of submandibular and sublingual glands
• supply of oral and nasal mucous glands

Question 9

What branches of the CN VII branch off abnormally to follow branches of CN V?

L21 S25

Answer 9

Greater petrosal nerve:

• branches of to merge with deep petrosal nerve
• synapses in pterygopalatine ganglion on CN V-3
• runs with zygomatic and lacrimal branches of CN V

Chorda tympani:
-branches to run with lingual nerve of CN V-3

Question 10

What are the modalities of CN IX?

L21 S27

Answer 10

Glossopharyngeal nerve

Special visceral motor (SVM):
-innervates stylopharyngeus muscle (derived from thrid pharyngeal arch)

General visceral motor (GVM):
-supply parotid gland

General visceral sensory (GVS):
-sensation of carotid body and carotid sinus

General somatic sensory (GSS):
-sensation of external ear, middle ear, and posterior 1/3 of tongue

Special visceral sensory (SVS):
-sensation of taste of posterior 1/3 of tongue

Question 11

Describe the SVM modality of CN IX.

L21 S28

Answer 11

Path:
-from nucleus ambiguous

Function:
-supply stylopharyngeus muscle (derived from third pharyngeal arch)

Question 12

Describe the GVM modality of CN IX.

L21 S28

Answer 12

Path:

• inferior salivatory nucleus (preganglionic)
• otic ganglion (postganglionic)

Function:
-supplies parotid gland

Question 13

Describe the GVS modality of CN IX.

L21 S30

Answer 13

Path:
-inferior ganglion

Function:
-sensation from carotid body and carotid sinus

Question 14

Describe the GSS modality of CN IX.

L21 S31

Answer 14

Path:
-from superior or inferior ganglion

Function:

• sensation of posterior 1/3 of tongue
• sensation of external ear
• sensation of middle ear

Question 15

Describe the SVS modality of CN IX.

L21 S32

Answer 15

Path:
-inferior ganglion

Function:
-sensation of taste from posterior 1/3 of tongue

Question 16

What are the modalities of CN X?

L21 S33-35

Answer 16

Vagus nerve

Special visceral motor (SVM):
-innervation of muscles derived from fourth and fifth pharyngeal arches

General visceral motor (GVM):
-supplies glands of pharynx, larynx, thorax, and abdomen

General visceral sensory (GVS):
-sensation from pharynx, larynx, thoracic viscera, and abdominal viscera

General somatic sensory:
-sensation of external ear and pharynx