Cranial Nerves Flashcards
From where do cranial nerves receive input?
From the cortex and nuclei in brainstem, exit through foramen. They run together with cranial nerves or cervical nerves.
Where do the cranial nerves exit the CNS?
Through the foramen.
What other nerves do cranial nerves run with?
They run with other cervical and cranial nerves.
where are upper motor neurons located?
cortex
How does upper motor neuron damage affect function?
Because there is bilateral input from the cortex, unilateral (damage on one side) damage doesn’t affect function.
What is the result of lower motor neuron damage?
paralysis of muscles on the affected side and loss of sense on affected side. Will see the effect unilaterally.
What does Cranial Nerve 5 (Trigeminal) provide sensation to?
face, scalp, oral and nasal mucous membrane, teeth, tympanic membrane. Ant 2/3 of tongue
What are the branches of CN 5 Trigeminal?
opthalmic, maxillary, Mandibular branch. Top 2/3 are sensory only, lower 1/3 is motor and sensory.
Where are lower motor neurons located?
In the brain stem or upper cervical spinal cord. Come out of brainstem and go into muslces on the SAME side.
To what muscles does CN 5 provide motor innervation ?
Masseter, ABD, medial pterygoid, lateral pterygoid, mylohyoid, temporalis, tensor veli palatini, tensor tympani
What are the the motor branches of CN 7?
There are 5 motor branches: temporal, zygomatic, buccal, mandibular, cervical.
To what muscles does CN 7 (Facial) provide motor innervation?
Motor control to all face muscles (frontalis, orbicularis oris, buccinator, etc.) Stylohyoid, posterior belly of digastric, stapedius
To what structures does CN 7 provide Taste innervation?
TASTE anterior 2/3 of tongue, floor of mouth, palate
To what structures does CN 7 provide Visceral Motor innervation?
PARASYMPATHETIC innervation of submandibular and sublingual gland, lacrimal gland, glands to nose and hard and soft palate
What is the Chorda Tympani of CN 7?
portion of facial nerve that provides taste to anterior 2/3 of tongue and submandibular and sublingual glands.
Rides on lingual nerve of CN 5 mandibular branch whcih gives general
What does upper motor neuron damage look like for the CN 7?
paralyiss of only LOWER facial muscles on CONTRALATERAL side. Emotionally motivated may still remain
What does CN7 lower motor neuron damage look like?
Paralysis of all muscles on affected side. Loss of sense on affected
Where is the lesion on CN7 if there is normal facial muscle function but loss of sensation?
Normal facial muscle function but loss of general tongue sense, lesion after chorda tympani leaves main nerve, but while it’s still with lingual nerve
Where is the lesion on CN7 if there is abnormal facial muscle function?
If abnormal facial muscle function, lesion is before nerve leaves the facial canal.
What muscle does CN 9 (Glossopharyngeal) provide motor innervation to?
Stylopharyngeus
What stuctures does CN 9 (Glossopharygeal) provide Sensory innervation?
posterior 1/3 of tongue, tonsils, skin of external ear, internal surface tympanic membrane, PHARYNX
What structures does CN9 provide Special Sensory innervation to?
Taste to posterior 1/3 of tongue
CN 9 Glossopharngeal Visceral
Stimulates parotid gland
CN9 Glossopharyngeal Visceral Sensory
provides subconsious sensation from carotid body and carotid sinus.
Carotid body
chemoreceptor that monitors O2 in blood. Less O2=increase in rate and depth of breathing
Carotid sinus
Baroreceptor. Monitors change in arterial blood pressure
CN9 Damage
Seldom isolated lesion, since closely associated with 10 and 11.
CN 10 Vagus branches
3 branches: Pharyngeal, Superior laryngeal nerve, recurrent laryngeal nerve
CN 10 Pharyngeal branch Motor
pharyngeal constrictors, levator veli palatini, salpingopharyngeus, palatopharyngeus, palatoglossus
CN10 Pharyngeal Branch Sensory
Gneral sense to pharynx.
CN 10 Pharyngeal Branch Visceral
Pharyngeal mucosa- control secretion
CN 10 Superior Laryngeal Nerve
Internal laryngeal= general and visceral sensory from base of tongue, epiglottis, aryepiglottic folds, and larynx to level of vocal folds.
CN 10 Superior laryngeal nerve motor functions
External laryngeal nerve provides motor to inferior constrictor and cricothyroid.
CN 10 Recurrent Laryngeal Nerve
Motor to the intrinsic muscles of the larynx (except the cricothyroid).
Provides general and visceral sensation from the vocal folds and the larynx below the level of vocal folds.
Right side path of recurrent laryngeal nerve
divides off vagus, hooks under SUBCLAVIAN artery, and ascends back to the larynx
Left side path of recurrent laryngeal nerve
divides off vagus, hooks under the aortic arch, and ascends back to the larynx
What does CN 10 provide General Visceral sensation to? and Motor
provides motor and visceral sensation to lungs-bronchioconstriction
esophogeal branches- speeds up persistalsis by acting on smooth muscles. Stimulates secretion of gastric glands for emptying stomach.
What are the two portions of Cranial Nerve 11 Accessory?
2 portions: cranial root and spinal root
What does the cranial root of CN 11 do?
joins pharyngeal branch of CN 10 to form pharyngeal plexus. Innervates with pharyngeal branch of CN10. At times considered part of CN 10
What does the Spinal root of CN 11 do?
motor to sternocleidomastoid and trapezius
What structures doe CN 12 Hypoglossal provide motor innervation to?
Motor: all intrinsic and extrinsic muscles of tongue except palatoglossus (CN10)
What does upper motor neuron damage to CN 12 Hypoglossal result in?
contralateral side affected, tongue deviates to opposite side from lesion.
What does lower motor neuron damage to CN 12 result in?
Ipsilateral side affected, tongue deviates toward side of lesion.
What moto nuclei are housed in the Pons?
house motor nuceli for 5 and 7
What moto nuclei are housed in the Medulla
CN 9, 10, cranial root 11, 12
What is housed in Cervical Spine C1-C5 or 6?
Spinal root of CN 11
What is the Reticular formation?
central part of brainstem (medulla and pons).
The nuclei within interact with cranial nerves.
What Nuclei are within reticular formation?
nucleus ambiguus, salivary nuclei, nucleus of tractus solitarius
What is the function of the Nucleus ambiguus
Motor nuclei, interacts with 9, 10, 11.
What is Salivary nuceli
Motor nuclei, above nucleus ambiguous, interacts with CN 7 and 9
What is the nucleus of tractus solitarius
VIsceral sensory nuclei. Recieves fibers from CN 7, 9, 10
