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108 Cards in this Set
- Front
- Back
- 3rd side (hint)
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What cranial nerve emerges between pyramids & olives?
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Hypoglossal CNXII
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What cranial nerve emerges lateral to olives?
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Vagus nerve
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what are the 3 sensory only nerves?
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olfactory (CN I), optic (CN II), and vestibulocochlear (CN VIII)
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What nerves are only somatic motor?
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trochlear (CN IV), abducent (CN VI), accessory (CN XI), hypoglossal (CN XII)
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Which nerves are somatic motor and sensory?
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trigeminal (CN V)
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Which nerves are somatomotor and parasympathetic?
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oculomotor (CN III)
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What nerves are somatic motor, sensory, and parasympathetic?
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facial (CN VII), glossopharyngeal (IX), and vagus (CN X)
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What does the olfactory nerve arise from and then what bone does it pass through? Where does it terminate? What is it's function?
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olfactory epithelium
cribiform plate primary olfactory cortex carrying afferent impulses for the sense of smell |
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What 4 things can cause an olfactory nerve lesion? what are the consequences?
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• Transient (non-neural): upper respiratory tract infection
• Fracture of cribriform plate • Frontal lobe tumor • Purulent meningitis or hydrocephalus anosomia- lessened sense of smell |
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how do you test CN I?
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Close eyes and smell one nostril at a time
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Where does CN II (Optic nerve) arise? Where does it decussate? Where does it synapse? What is its function?
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retina
optic chiasm thalamus carrying afferent impulses for vision |
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Info from left or right visual field is carried to (ipsolateral/contralateral) visual cortex
Info from upper or lower visual field is carried lower or upper side, respectively, of _____________ |
contralateral
calcarine fissure |
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What are the 3 ways to test optic nerve (CN II)?
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visual acuity, visual fields, and fundoscopy
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What are the 3 oculomotor nerves?
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CN III (oculomotor), IV (trochlear), & VI (abducent)
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What are the 6 extraocular muscles?
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Superior rectus (rectus = straight) attaches to the top of the eye Contraction pulls the eye up & out (elevate & ABduct)
Inferior rectus attaches to the bottom of the eye Contraction pulls the eye down & out (depress & ABuct) Lateral rectus on the lateral margin medial rectus along medial margin Inferior and superior obliques (responsible for torsion & extortion) are attached on a diagonal |
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What are the innervations of the oculomotor nerve?
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CN III Oculomotor:
superior rectus elevates inferior rectus depresses medial rectus adducts inferior oblique elevates AD-ducted eye extorts AB-ducted eye |
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What are the innervations of the trochlear nerve?
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CN IV Trochlear:
superior oblique: depresses AD-ducted eye intorts AB-ducted eye |
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What are the innervations of abducens nerve?
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CN VI Abducins:
lateral rectus (ABducts) |
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What are the actions of the obliques?
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inferior oblique
- elevates AD-ducted eye - extorts AB-ducted eye superior oblique: - depresses AD-ducted eye - intorts AB-ducted eye |
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A value above an FEV1/FVC of .8 is what type of lung disease?
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restrictive
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What does the parasympathetic bodies of oculomotor (CN III) control?
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sphincter of the pupil (causes constriction) and the ciliary muscle of the lens (causing accommodation)
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What nerves emerges from interpeduncle fossa, between the PCA and SCA?
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CN III, oculomotor
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What does an aneurism pComm cause a lesion?
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CN III
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Where do you find the motor nucleus of CN III, oculomotor?
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rostral midbrain, near midline (motor = middle), ventral to periaqueductal gray region
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What is the parasympathetic nucleus for the oculomotor nerve (CN III)?
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Parasympathetic nucleus = Edinger-Westphal, located just dorsal to motor for CN III
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What does the oculomotor nerve pass through in terms of bony structures?
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Passes through lateral wall of cavernous sinus & superior orbital fissure
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What are consequences of oculomotor (CN III) lesions?
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Eye position: down & out (downward & ABducted)
strabismus (eyes not directed towards same object) diplopia (double vision) Ptosis (lid droop) Pupil dilation (mydriasis) and loss of accommodation Accommodation = the process whereby the eye maintains a clear image (focus) of an object as its distance changes |
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What causes lesions of the oculomotor (CN III) nerve?
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Aneurysm, inflammation, cavernous sinus lesion, temporal lobe herniation
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What is the Pupillary Light Reflex?
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The afferent (sensory) limb of the pupillary light reflex is CN II while the efferent (motor) limb is the parasympathetics of CN III
Shine a light into each eye noting the direct as well as the consensual constriction of the pupils Swinging the flashlight back and forth, noting the size of both pupils, identifies if one pupil has less perception than the other. |
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Where do fibers of the trochlear nerve (CN IV) emerge? How does CN IV enter the orbit? what muscle does it innervate? What does a lesion of CN IV cause?
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dorsal midbrain
via the superior orbital fissures superior rectus difficulty moving the eye inferior and lateral, which leads to double vision |
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Where is the trochlear (CN IV) nuclei? Where does the nerve emerge? which muscles does it innervate and which side?
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the midbrain, caudal to the oculomotor nucleus
dorsally, caudal to the inferior colliculi The LMN axons cross the midline in the dorsal midbrain, Each Trochlear nucleus innervates the superior oblique muscle of the contralateral eye |
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What are the consequences of a trochlear nerve lesion (CN IV)? What are causes and effect?
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head tilt- eyes rotate opposite to tilt
Causes: Aneurysm, inflammation, cavernous sinus lesion, temporal lobe herniation Effects: Strabismus, diplopia, extortion, weakness in depression & ABduction of gaze |
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What is the purpose of abducens nerve (CN VI)?
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- Somatic motor (general somatic efferent) component - Innervates the lateral rectus muscle (ipsilateral orbit
The lateral rectus muscle is responsible for lateral gaze (contraction causes the eye to ABduct) |
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Where is the abducens (CN VI) nucleus?
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pons
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Where does the abducens (CN VI) emerge?
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medially, between the pons and medulla
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How do you compensate for a abducens CN VI lesion? What are causes and effects?
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turn head contralaterally to align gaze
Causes: Aneurysm, inflammation, cavernous sinus lesion, increased ICP, fourth ventricle lesions, lesions within superior orbital fissure, skull base fractures Effects: Strabismus, diplopia, inability to ABduct past midline |
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What causes diplopia (double vision)?
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CN III oculomotor, IV trochlear and VI abducens
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What connects abducens VIth nerve nucleus to the oculomotor III nerve nucleus for conjugate eye movement?
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medial longitudinal fasciculus (MLF)
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What are the 3 divisions of trigeminal?
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Ophthalmic (V1)
Maxillary (V2) Mandibular (V3) |
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Which branch of trigeminal (CN V) provides motor fibers for mastication?
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V3- mandible
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Tic douloureux or trigeminal neuralgia
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- Most excruciating pain known (?)
- Caused by inflammation of nerve - In severe cases, nerve is cut; relieves agony but - Results in loss of sensation on that side of the face |
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What virus targets the trigeminal nerve?
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Opthalmic herpes zoster
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What are the parts of the trigeminal nerve?
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Yellow = mesencephalic (proprioception)
blue = masticator (motor) orange = main trigeminal (fine touch) green= spinal trigeminal (pain/temp) |
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What nerve provides sensory information to the face?
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trigeminal nerve (CN V)
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Where do the fibers for facial nerve (CN VII) leave and travel?
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leave the pons, travel through the internal acoustic meatus, and emerge through the stylomastoid foramen to the lateral aspect of the face
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What are the motor, parasympathetic, and sensory functions of facial nerve (CN VII)?
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Motor functions include;
Facial expression Transmittal of parasympathetic impulses to lacrimal and salivary glands (submandibular and sublingual glands) Sensory function is taste from taste buds of anterior two-thirds of the tongue |
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Where does the facial (CN VII) nucleus lie? Where do the facial nerves emerge?
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The facial motor nucleus is in the pons
The nerves emerge laterally, between the pons and medulla |
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What causes Bell's palsy?
What are the symptoms? |
herpes
Lower eyelid droops Corner of mouth sags Tears drip continuously and eye cannot be completely closed (dry eye may occur) Condition my disappear spontaneously without treatment |
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When do you have contralateral and ipsilateral effects of facial nerve (VII) lesion?
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UMNL (upper motor neuron lesion) Supranuclear (cortex)
Contrlateral effects on lower quadrant only Upper quadrant receives input from both hemispheres Whereas lower quadrant only contralateral input LMNL (Lower motor neuron lesion) Lesion of facial nucleus or more peripheral Ipsilateral effects on both upper and lower quadrants of the face |
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What controls the different parts of the corneal reflex?
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Opthalmic division V1 of CN V, is the sensory component of corneal reflex and branch of VII nerve is the motor component
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Where does the CN VIII: Vestibulocochlear emerge? What are the 2 divisions?
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Fibers arise from the hearing and equilibrium apparatus of the inner ear, pass through the internal acoustic meatus, and enter the brainstem at the pons-medulla border
Two divisions : -cochlear (hearing) and -vestibular (balance) |
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What is a weber test? Which nerve does it affect?
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Weber Test: Place a vibrating tuning fork on the middle of the head and ask if the person hears or feels it better on one side Normal= same on both sides
Unilateral neurosensory hearing loss = better on normal side Unilateral conductive hearing loss = hear better in abnormal ear CN VIII Vestibulocochlear |
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What is the rinne test? What nerve does it control?
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Rinne test: Comparing Bone versus air conduction (Place the tuning fork on the mastoid, or in front of the pinna) normally air conduction is faster than bone. Ask witch sounds louder For neurosensory loss air is faster than bone, in contrast in conduction hearing loss bone conduction will be faster than air
Vestibulocochlear (CN VIII) |
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What will tumors with in the auditory meatus (acoustic neuromas, meningiomas)?
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CN VIII and CN VII
vestibulotrochlear facial |
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What CN IX glossopharyngeal nerve travel?
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Fibers emerge from the medulla, leave the skull via the jugular foramen, and run to the throat
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What are the functions of CN IX: Glossopharyngeal?
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Motor – innervates part of the tongue and pharynx, and provides motor fibers to the parotid salivary gland
Sensory – fibers conduct taste and general sensory impulses from the tongue and pharynx |
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What are the functions of the vagus nerve?
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Most motor fibers are parasympathetic fibers to the heart, lungs, and visceral organs
Its sensory function is in taste |
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Where does the vagus nerve (CN X) emerge?
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Fibers emerge from the medulla via the jugular foramen
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What 2 cranial nerves share control of speech and swallowing?
Where do both of them originate? |
Glossopharyngeal (CN IX) & Vagus (CN X)
nucleus ambiguus in the medulla |
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What two nerves control the gag reflex and "ahhh"?
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glossopharyngeal (IX) and vagus (X)
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What is the origin of accessory nerve (CN XI)? Where does it travel? What does it do?
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Formed from a cranial root emerging from the medulla and a spinal root arising from the superior region of the spinal cord
The spinal root passes upward into the cranium via the foramen magnum The accessory nerve leaves the cranium via the jugular foramen Primarily a motor nerve Supplies fibers to the larynx, pharynx, and soft palate Innervates the trapezius and sternocleidomastoid, which move the head and neck |
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Where does the hypoglossal nerve emerge? What does it do?
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Fibers arise from the medulla and exit the skull via the hypoglossal canal
Innervates both extrinsic and intrinsic muscles of the tongue, which contribute to swallowing and speech If damaged, difficulties in speech and swallowing; inability to protrude tongue |
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What is the result of Trochlear Nerve Palsy?
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Loss of Control of Contralateral Superior Oblique Muscle
Tilt head towards good eye – both eyes in primary position Tilt head towards bad eye – Affected Eye > dramatic elevation |
- depresses AD-ducted eye
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What happens in trochlear nerve lesion?
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Weak eye extorts
patient cannot look down & in often becomes obvious when patient goes down stairs Likely vertical diplopia tilt head to good side to ‘fix’ diplopia (torticollis = twisted neck) |
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What does abducens nerve (CN VI) innervate? What happens in lesions?
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lateral rectus muscle
Patient cannot look laterally beyond midline |
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What can destroy abducens nerve (CN VI)?
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increased ICP
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What coordinates eye movement?
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Brainstem GAZE CENTERS
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What are the brainstem gaze centers?
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Vergence gaze center (eyes to look out and in)
Vertical gaze center (eyes to look up and down) 2 Horizontal gaze center (right & 1 to look left) |
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Where is the vergence center?
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Vergence center is located near the oculomotor nuclei of the midbrain (NOT surprising when we consider that these movements rely upon the medial rectus muscle)
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What is the purpose of vergent eye movement?
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Allows tracking of objects moving towards/away
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What muscles need to contract to allow you to focus on objects coming towards you?
Innervated by which CN? |
Eyes AD-ducting
Both medial rectus Oculomotor CN III |
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What is vergence?
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eye movements occur when the eyes move simultaneously inward (convergence) or outward (divergence) in order to maintain the image on the fovea
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Near Reflex Triad
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Sensory input: Object moves closer, becomes blurry
Integration: Information reaches visual cortex and is relayed to brainstem Motor output: Convergence: medial rectus bilaterally = Oculomotor Nucleus Accommodation: lens thickens (ciliary muscles) = Edinger-Westphal Miosis: pupillary constrictor muscles = Edinger Westphal (parasympathetics) |
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Vertical Gaze Center
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Located near nerves necessary for vertical gaze, i.e., in dorsal mesencephalon
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To generate conjugate eye movements, need to access to:
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- a lateral rectus (Abducens Nerve, CN VI) and
- the contralateral medial rectus (Oculomotor Nerve, CN III) |
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What is the tract contained interneurons which run from Abducens Nucleus (VI) to Oculomotor (III)?
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MLF (medial longitudinal fasciculus)
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Bilateral INO is pathognomonic for _______________
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MS
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Lateral/Horizontal Gaze Center Anatomic designation
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Paramedian Pontine Reticular Formation (PPRF)
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Right lateral gaze center coordinates lateral gaze to ____________
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right
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Lesion to right CN VI nuc or PPRF results in inability to direct
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either eye to the right
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Lesion to right MLF results in loss of ability of
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right eye to look left on left lateral gaze. Left eye can look left on left gaze; all other lateral
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What are the 2 conjugate movements?
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Saccades
move the fovea to point at a new target (target acquisition) FAST (rapid jumps) Smooth Pursuits keep the fovea pointing at a moving target SLOW |
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What are saccades?
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Very rapid (900°/sec)
Can be voluntary, i.e. can choose direction, target Can be in response to many sensory stimuli (visual, auditory, tactile, memory) |
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What do Frontal Eye Fields do? Right FEF in right frontal lobes drives eyes __________
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triggering voluntary saccades
left |
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Superior colliculus triggers many ____________
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reflexice saccades
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What are smooth movements?
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Tracking to keep a moving image on fovea
Activated in response to moving visual stimulus (retinal slip) Slower than saccades : max speed about 100°/sec Cortical, brainstem, and cerebellar inputs are required to produce smooth pursuits Adversely affected by drugs, alcohol, fatigue, inattention (distractions) |
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What hemisphere effects smooth pursuits?
What do lesions of smooth pursuit circuits cause? Where does voluntary smooth pursuit originate and involve? |
Each hemisphere drives pursuits into ipsilateral visual space.
Patients with lesions within the smooth pursuit circuits generally cannot pursue targets moving towards the damaged side. Voluntary smooth pursuits originate near the angular gyrus, involve: vestibular nuclei, flocculonodular lobe of cerebellum Abducens nucleus (predictably) |
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What are optokinetic and vestibulo-ocular reflexes?
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Optokinetic reflexes:
keep the fovea on target during slow, sustained movements of head or target use visual feedback Vestibulo-ocular reflexes: keep the fovea on target during rapid & jerky head movements NO time for visual feedback! Use vestibular inputs |
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What happens when damage Right FEF (Frontal Eye Field)?
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No command reaches brainstem eyes don't move left
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Acute Stroke loose Right FEF
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Possible “right gaze preference" due to unopposed left frontal eye fields activity
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Damage to Left Abducens Nerve
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Abducens nuc. cannot access left eye, so no left eye abduction
Abducens nuc CAN contact oculomotor: hence right medial rectus = right adduction |
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Damage To Left Abducens Nucleus region
No LMNs to lateral rectus: No cells bodies of MLF neurons |
- Ipsilateral eye does not AB·duct
- message does not get to right Oculomotor - and contralateral eye does not AD·duct so neither eye looks left (both eyes may deviate right) |
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Damage to Right Oculomotor Nerve or Nucleus
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left eye looks left
no control over right eye medial rectus (or superior rectus, inferior rectus, inferior oblique) eye down & out also lose control over levator palpebrae superioris eyelid droops (ptosis) and loss of parasympathetic pupil dilates (mydriasis) |
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What are the mammilary bodies and infundibulum?
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Mammilary bodies: olfactory reflexes and emotional responses to odors
Infundibulum: stalk extending from floor; connects hypothalamus to posterior pituitary gland. Controls endocrine system. |
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What provides much of the hypothalamic blood supply?
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P comm
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What is the point of the hypothalamus?
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Blood pressure
Body temperature Fluid and electrolyte balance, and Body weight |
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What provides much of the hypothalamic blood supply?
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P comm
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What are the hypothalamic inputs?
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Nucleus of the solitary tract- collects all the visceral sensory information from the vagus and relays it to the hypothalamus & other targets (blood P2, gut distention)
Reticular Formation- receives a variety of inputs from the spinal cord (skin temp) Retina- some fibers from the optic nerve go directly to the suprachiasmatic nucleus. (regulates circadian rhythms and couples them to light/ dark cycles Limbic and olfactory systems- the amygdala, the hippocampus and the olfactory cortex project to the hypothalamus (help regulate eating and reporduction) |
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What are the hypothalamic outputs?
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Neural signals to the autonomic system- The lateral hypothalamus projects to the lateral medulla. Where the cells that drive the ANS are located. These include: the parasympathetic vagal nuclei and a group of cells that descend to the sympathetic system in the spinal cord. – the hypothalamus controls heart rate, vasoconstriction, digestion, sweating, etc.
Endocrine signals to/through the pituitary- Magnocellular neurons send axons directly to the posterior pituitary and secrete oxytocin and vasopressin directly into the bloodstream. Parvocellular neurons secrete peptides that regulate the release of anterior pituitary hormones. |
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What does not normally effect steady locomotion?
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cortex
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What spinal network normally generates the basic locomotor pattern?
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central pattern generator
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What can initiate and terminate locomotion activity via CPGs?
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The basal ganglia
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What optimizes the locomotor pattern?
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The cerebellum
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Spinal locomotor CPGs are activated by thalamus (subthalamic region) or reticularspinal neurons?
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Both
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What do CPGs require?
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require ONLY:
sensory input local spinal cord circuitry motor output |
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Does the thalamus increase or decrease movement?
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increase
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What is the effect of the striatum on motor output?
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Striatum Inhibits SNr Gpi Inhibition (=* (activation) of the thalamus via Cerebral cortex leads to INCREASED Motor output
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What disease causes enlargement of the ventricles?
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Huntington's
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