Cranial Nerves for speech

Question 1

What is the sensory function of trigemenial nerve (CN V)?

Answer 1

Carries pain, touch, and temperature from the sinuses, mucous membranes, and skin of the face

Question 2

What is the motor function of CN V?

Answer 2

Through the mandibular branch only, it innervates the muscles of mastication, tensor tympani (middle ear muscle), tensor veli palatini (tenses the soft palate), anterior belly of digastricus, and mylohyoid

Question 3

What happens if CN V is damaged?

Answer 3

unable to close your mouth; difficulty chewing; sharp pain in your face (trigeminal neuralgia)

Question 4

What is the sensory function of CN VII?

Answer 4

Carries sensory information from the anterior 2/3 of the tongue

Question 5

What is the motor function of CN VII?

Answer 5

innervates muscles of facial expression

Question 6

What happens if CN VII is damaged?

Answer 6

mask-like facial appearance and littel to no facial expression

Question 7

What is CN VIII?

Answer 7

Vestibulocochlear nerve; it has a vestibular branch and an acoustic branch. The vestibular branch maintains balance, whereas the acoustic branch sends auditory information from the cochlea to the primary auditory cortex where sound is interpreted

Question 8

What is the sensory function of the glossopharyngeal nerve?

Answer 8

it carries sensation from the posterior 1/3 of the tongue and sensation from the tonsils, pharynx, soft palate, tympanic membrane, eustachian tube, ear canal

Question 9

What is the motor function of the glossopharyngeal nerve?

Answer 9

it innervates the stylopharyngeus muscle (responsible for raising and dilating the pharynx) and may provide motor fibers to the pharyngeal plexus which innervates the upper pharyngeal constrictor muscles

Question 10

What is the sensory function of the vagus nerve?

Answer 10

provides taste sensation to the epiglottis and root of the tongue; provides visceral sensation to the abdominal viscera and heart; provides sensory information from the skin of the external auditory meatus, laryngopharynx, and larynx

Question 11

What is the motor function of the vagus nerve?

Answer 11

innervates most of the muscles of the pharynx, larynx, and soft palate

Question 12

What is the parasympathetic function of the vagus nerve?

Answer 12

regulates heart rhythm; innervates the smooth muscle of the trachea, GI tract, and bronchi

Question 13

What does the pharyngeal branch of CN X do?

Answer 13

since it is only motor, it innervates the palatoglossus muscle (extrinsic tongue muscle or a velar muscle), all pharyngeal muscles except for the stylopharyngeus muscle; all velar muscles (levator veli palatini and musculus uvulae) except for the tensor veli palatini

Question 14

What happens when the pharyngeal branch of CN X is damaged?

Answer 14

All the muscles innervated by it are weakened ipsilaterally. Thus, a weakened soft palate leads to hypernasality since the palate cannot close off the velopharyngeal port so air will escape. Weakened pharyngeal muscles entails difficulty getting the bolus down from the pharynx to the esophagus. It also causes a buildup of food/drink in the piriform sinuses.

Question 15

What does the superior laryngeal nerve of CN X do?

Answer 15

has an internal branch and an external branch. Internal branch = carriers taste sensation from the epiglottis and esophagus as well as carries pain, touch, and temperature signals from the epiglottis and larynx above the vocal folds.
External branch = innervates the cricothyroid muscle and inferior pharyngeal constrictor muscle

Question 16

What happens when the superior laryngeal nerve of CN X is damaged?

Answer 16

reduces sensation of the superior portion of the laryngeal muscles which increases the risk of aspiration and penetration and reduces the gag reflex; it also can make it difficult to change vocal pitch

Question 17

What does the recurrent laryngeal branch of CN X do?

Answer 17

It controls all the intrinsic muscles of the larynx except for the cricothyroid muscle

Question 18

What happens if the recurrent laryngeal branch of CN X is damaged?

Answer 18

vocal fold paralysis or ipsilateral paresis; increases risk of aspiration and penetration; breathy and hoarse vocal quality; diplophonia may result

Question 19

What is the pharyngeal plexus?

Answer 19

bunch of nerves formed from the branches of the glossopharyngeal nerves and vagus nerves that innervate the pharynx and are crucial for swallowing

Question 20

What is the function of the hypoglossal nerve (CN XII)?

Answer 20

Innervates all extrinsic tongue muscles except for palatoglossus: styloglossus, genioglossus, and hyoglossus; innervates all intrinsic tongue muscles as well.

Question 21

What happens if CN XII is damaged?

Answer 21

swallowing problems; paralyzed tongue; and diminished intelligibility

Question 22

What is the function of the spinal accessory nerve (CN XI)?

Answer 22

controls the trapezius and sternocleidomastoid muscles