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33 Cards in this Set
- Front
- Back
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What do the cranial nerves do?
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The 12 cranial nerves provide sensory & motor innervation primarily to the head & neck
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Name the mnemonic device for remembering the 12 nerves, and then say what each nerve is.
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Oh, Once One Takes The Anatomy Final, Very Good Vacations Are Had.
Olfactory, Optic, Oculomotor, Trochlear, Trigeminal, Abducens, Facial, Vestibulocochlear, Glossopharyngeal, Vagus, Accessory (spinal), Hypoglossal |
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What is the mnemonic for remembering whether the CN is sensory, motor, or both?
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Some Say Marry Money, But My Brother Says Big Brains Matter More
Olfactory - Sensory Optic - Sensory Oculomotor - Motor Trochlear - Motor Trigeminal - Both Abducens - Motor Facial - Both Acoustic - Sensory Glossopharyngeal - Both Vagus - Both Accessory - Motor Hypoglossal - Motor |
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Say which CNs go to which part of the brainstem.
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I & II -- (forebrain)
III & IV -- midbrain V thru VIII -- pons IX thru XII 00 medulla |
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What is CN I and what is its function?
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CN I = Olfactory; it is primarily sensory; function is smell
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What is CN II and what is its function?
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CN II = Optic; it is primarily sensory; function is vision. Will have more notecards later when we get to the Optic Tract
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What is CN III and what is its function?
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CN III = Oculomotor. Eye motor. Nuclei in midbrain. 4 of the 6 eye muscles controlled by oculomotor nerve. Involved in reflex reaction to light.
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What is CN IV and what is its function?
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CN IV = Trochlear; motor (eye). Nuclei in midbrain. 5th of the 6 muscles to eye.
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What is CN V and what is its function?
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CN V = Trigeminal. Mixed: both sensory & motor. Nuclei in pons (pontine nuclei).
Sensory branch: 3 major divisions correspond to 3 places on face. --> Ophthalmic division: sensory to forehead/eyes --> Maxillary division: sensory to upper lip, palate, nasal --> Mandibular division: sensory to lower jaw, lower lip, anterior 2/3 of tongue -- pain, pressure, temp, NOT taste Motor branch: --> muscles of mastication (temporalis & masseter) --> tensory tympani (Acoustic Reflex!) --> tensor veli palatini --> mylohyoid --> anterior belly of digastric |
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What is CN VI and what is its function?
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CN VI = Abducens. Motor (eye). 6th muscle of eye; extrinsic. Nuclei in pons.
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What is CN VII and what are its functions?
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CN VII = Facial; Mixed (sensory/motor). Nuclei in pons.
Motor to: --> stapedius (Acoustic Reflex!) --> stylohyoid --> posterior belly of digastric --> all muscles of facial expression --> visceral muscles/glands: tear glands, mucous membranes of nose, hard/soft palate Sensory from: --> concha of auricle --> walls of EAM --> external portion of TM --> TASTE from anterior 2/3 of tongue --> hard & soft palate |
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CN VII (Facial) has ___________ innervation which is both _________ and _________
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Facial nerve has BILATERAL innervation which is both IPSILATERAL and CONTRALATERAL
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Motor for Facial Nerve: fibers that project to forehead have ________ representation, but remaining lower facial muscles are ____________ and ____________.
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Motor for Facial Nerve: fibers that project to forehead have BILATERAL representation, but remaining lower facial muscles are UNILATERAL and CONTRALATERAL. (i.e. L cheek innervated by R side motor strip; R cheek innervated by L side motor strip)
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What are teh reflexes mediated by the Facial Nerve?
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- Corneal reflex (close eye)
- Stapedius (response/protection from loud noise) - Sucking (response to touching sensation near mouth) |
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Damage to UMNs re: facial motor: what level of the brain is this, and what will be the result on the face?
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UMN is at the level of the cortex (cell body or axon).
Forehead is OK on contralateral side (because there is bilateral rep; ie. both contra AND ipsi representation) Lower face NOT ok on contralateral (it only has uni/contral innervation) --> common with dysarthria; drooling |
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What is CN VIII and what is its function?
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CN VIII = Vestibulocochlear (aka Acoustic). Sensory, nuclei in pons. Somatic, affarent; carries 2 special sensations:
- vestibular from semi-circular cnals; - auditory from cochlea, via 8th aud nerve |
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What is CN IX and what is its function?
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CN IX = Glossopharyngeal. Mixed sensory/motor.
Motor to: --> stylopharyngeus (elevates pharynx; mostly during swallowing & speech, changing pitch) --> involuntary motor to salivary glands Sensory from: --> thorax, abdominal organs, respiration control --> posterior 1/3 of tongue (everything -- pain, touch, temp, and taste) --> pinna --> internal surface of TM --> gag reflex |
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What is CN X and what is its function?
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CN X = Vagus nerve "the wanderer." Mixed sensory/motor (exits brainstem/medulla)
Motor to: --> striated (vol) muscles of pharynx, larynx, tongue, palatoglossus --> smooth (invol) muscles of pharynx, larynx, thoracic & abdominal viscera Sensory from: --> larynx, trachea, esophagus, abdominal viscera, thorax --> pharynx, skin from back of pinna --> EAM --> part of exyernal surface of TM |
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Branches of the Vagus nerve. Describe the motor branches.
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Motor fibers exit the Vagus as 3 major branches:
1) pharyngeal branches 2) superior laryngeal branches (2 divisions: internal, external) 3) recurrent branches |
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Describe the pharyngeal nerve.
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Pharyngeal nerve is one of the branches of the Vagus nerve. Principle motor nerve of pharynx. Enters upper border of middle pharyngeal constrictor muscle.* Branches off, continues dividing -- "pharyngeal plexus."
*Other constrictor muscles: - superior constrictor - middle constrictor - inferior constribor - cricopharyngeus Pharyngeal component innervates: - all three constrictor muscles (swallowing) - all muscles of soft palate (elevate/lower)= --- palatal levator --- palatopharyngeus --- salpingopharyngeus --- palatoglossus (elevates tongue) |
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What are the branches of the superior laryngeal nerve and what do they do?
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There are 2 branches of the superior laryngeal nerve, which is a branch of the Vagus nerve.
Internal superior laryngeal = sensory. External superior laryngeal = motor.----> - Goes through constirctor muscles, further down - Supplies ONLY cricothyroid muscle - Lengthens vocal folds (tension up, pitch up) |
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Describe the recurrent laryngeal nerve.
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Recurrent nerve is a branch of the vagus nerve.
Takes different paths on R/L Right: down anterior; hooks under sublavian artery Left: longer than right; hooks under aortic arch - Both enter larynx in groove between trachea & esophagus - innervates all intrinsic muscles of larynx, except CT (which is innerv. by external sup laryngeal branch of vagus) |
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R v. L sides of recurrent laryngeal nerve: what are the disadvantages of the left side?
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1. it's longer - more opportunity for damage
2. it wraps around aorta, can be affected by heart surgery (but may regenerate) |
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T/F: Nerves in PNS can regenerate, while nerves (axons) in CNS will not regenerate.
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TRUE
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What are the intrinsic muscles of the larynx and what nerve branches are they each innervated by?
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Cricothyroid muscle --> external superior laryngeal branch of vagus
Thyroarytenoid muscle --> recurrent laryngeal branch of vagus Thyrovocalis muscle (recurrent laryngeal branch of vagus) |
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Upper motor neurons re: Vagus nerve are always ________.
Lower motor neurons are always ___________. |
UMN = contralateral
LMN = ipsilateral |
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Unilateral lesion in Vagus nerve itself (higher up before branching off) -- what are the results?
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Everything is affected; there is no longer innervation of muscles on one side.
VFs don't meet/meet poorly--> hoarseness Swallowing problems: constrictor muscles on one side,elevating soft palate, nasality In an OPE: A lesion on the right side will present a droop on the affected side. Uvula deviates to unaffected side (good side), away from side of lesion, because of unopposed force. |
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Unilateral lesion to pharyngeal branch of Vagus -- what are the results?
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Swallowing problems
Constrictor muscles affected Hypernasality, ipsilateral path of palate Too much air going into nasal cavity No problems with voicing: (pharyngeal branch doesn't innervate CT) |
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Unilateral lesion to recurrent branch of Vagus -- what are the results?
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No swallowing or hypernasality problems
Paralysis of VFs & all muscles on that side (hoarseness) Depends on where VFs are when damage occurs Surgery: nerve severed, nicked, stretched Left recurrent nerve more vulnerable than right recurrent VFs innervated by either R/L recurrent nerve 4 positions where VGs can be paralyzed |
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What is CN XI and what is its function?
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CN XI = Spinal Accessory. Motor; nuclei in medulla.
"special" cranial nerve: supplies muscles: - sternocleidomastoid (neck; visceral, glands) - trapezius (shoulder. In radical laryngectomy, will sever CN XI, will have droopy shoulder) - pharynx, larynx, SP, uvula, palatal levator (mini-assistant to Vagus) |
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What is CN XII and what is its function?
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CN XII = Hypoglossal. Motor; nuclei in medulla.
Supplies all intrinsic & extrinsic muscles of the tongue (except palatoglossus -- Vagus) Intrinsic muscles of tongue: - mylohyoid - geniohyoid Extrinsinc muscles of the tongue: - genioglossus - styloglossus (styloid proc of temporal bone --> tongue) Corticobulbar tract crosses over at pyramids (contralateral innervation); loops around greater cornu of hyoid -- innervates hyoglossal muscle on the way to tongue (between hyoid & tongue) |
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If the lesion to the hypoglossal nerve (or rather its corticobulbar tract) is in the UMNs, what will the damage be?
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contralateral; e.g. if lesion on left side of corticobulbar tract, left side of tongue will be OK but right side will deviate to right (contralateral to lesion). Tongue deviates ipsilateral to weakness because no even action on the R side.
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If the lesion to the hypoglossal nerve is in the LMN, what will the result be?
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Damage to LMN means it happens after cross-over in the pyramids. Tongue will deviate ipsilateral to lesion (e.g. lesion on R side, tongue will deviate to R side b/c no resistance to L side pushing toward midline)
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