L8 Cranial Nerves IX-XII Flashcards
Origins of the Glossopharyngeal Nerve (CN IX)?
Leaves Medulla Oblongata dorsal to the Olive
Origins of the Vagus Nerve (CN X)?
Leaves Medulla Oblongata dorsal to the Olive
Origins of the Accssory Nerve (CN XI)?
Emerges via rootlets from the Upper Cervical Cord
Origins of the Hypoglossal Nerve (CNXII)?
Leaves between the Pyramids and Olives (Upper Medulla) by many roots
What nerves pass through the Jugular Foramen?
Cranial nerves IX, X, and XI, originate from the brainstem and exit the cranium via the jugular foramen
Which nerve is responsible for the Gag Reflex?
Glossopharyngeal Nerve (CNIX)
Functions of the Glossopharyngeal Nerve (CN IX)?
Sensory: SVA, GVA, GSA
Motor: SVE, GVE
Sensory
SVA: Taste (Posterior ⅓ Toungue)
GVA:
- Carotid Body (O2, CO2, pH)
- Carotid Sinus (Baroreceptors)
- Oropharynx (Gag Refelx)
GSA:
- Middle Ear
- Posterior ⅓ of Toungue
- Upper Pharynx
Motor
- SVE: Stylopharygeous
- GVE: Secretomotor to Parotid Gland
Origins/Pathways of Glossopharyngeal Nerve (CN IX)?
The brachial motor portion (SVE) of the Glossopharyngeal Nerve (CN IX) supplies which one muscle?
What is the role of this muscle?
Where does the nerve originate?
Stylopharyngeus
Elevates pharynx during talking/swallowing
Originates in the Nucelus Ambiguus
Supply of the Parotid Gland?
Describe the Gag Reflex?
Irritant on posterior toungue=> Afferent through Glossopharyngeal Nerve to the Nucleus Solitarius => Interneuron to Nucleus Ambiguous => lower motor neurons leave Nucleus Ambiguous via Vagus Nerve to various constrictors of GI tract => GAG Reflex
To what nucleus are taste fibers of the Poster ⅓ of the tongue directed?
Glossopharyngeal Nerve (CN IX)=> Nucleus Solitariues
To what nucleus are input from baro/chemoreceptors at the carotid as well as the Pharyngeal Wall (Gag Reflex) Directed?
CAUDAL Nucleus Solitariues => Glossopharygeal Nerve (CN IX)
Describe the Pathway/Nucelus involved in innervation of the Parotid Gland
Preganglionic fibers arise from Inferior Salivatory Nucleus => Leave CNIX via Tympanic Nerve & join Lesser Petrosal Nerve to synapse in Otic Ganglion => Postganglionic neurons supply Parotid Gland
Origins/Pathways of Vagus Nerve (CN X)?
How to test Cranial Nerves IX/X?
Innervation of the Trapezius and Sternocleidomastoid?
Accessory Nerve CNXI Arises from Spinal Accessory Nucleus:
- Contralateral supply to TRAPEZIUS
- Ipsilateral supply to STERNOCLEIDOMASTOID (rotates head to contralateral side)
How to test Cranial Nerve XI?
How to test Cranial Nerve XII?
Effect of Lower vs. Upper Motor Neuron Lesion of CNXII?
LMN Lesion: Tongue deviates to SAME side as lesion
UMN Lesion: Tongue deviates to CONTRALATERAL side of lesion
