Neurology (02/02) Cranial Nerves V & VII Flashcards
injury to the abducens nerve results in ____ ____
medial strabismus
concerning the pupillary reflex, the efferent limb is the _____ nerve
oculomotor
concerning the pupillary reflex, input from cranial nerve II is sent where?
edinger westphal nucleus (bilaterally)
accommodation includes what three things?
- contraction of ciliary m to all lens to thicken centrally
- convergence of eyes by slight inc in medial rectus m tone bilaterally
- contraction of sphincter pupillae to constrict pupils
where does the trigeminal nerve come off of the brain?
lateral pons
where does the facial nerve come off of the brain?
between pons and cerebellum (cellebopontine angle)
what nerve runs directly in the middle of cranial nerve VII?
nervus intermedius
what is the general sensory nerve for the head?
CN V
concerning CN V, what is the CNS origin of the somatic sensory division concerned with muscle spindles and other mechanoreceptors?
mesencephalic nucleus
concerning CN V, what is the CNS origin of the somatic sensory division concerned with skin and deep tissues of head and dura?
spinal and main sensory nuclei
concerning CN V, what is the CNS origin for the brachial division concerned with muscles of mastication and the tensor tympani and others?
trigeminal motor nucleus
CN V transmits ____, _____, _____ and _____ from the head to cortex, cerebellum, and reticular formation
- tactile
- proprioceptive
- pain
- temperature
CN V is to the head with _____ and _____ are to the body
- dorsal root ganglia
- dorsal roots
Vi is concerned with the ____ ____ and is ____ only
- upper face
- sensory
Vii is concerned with the _____ ____ and is ____ only
- middle face
- sensory
Viii is concerned with the ____ ____ and is _____
- lower face
- sensory and motor
concerning CN V, what is the CNS nucleus that can be found in the midbrain?
trigeminal mesencephalic nucleus
concerning CN V, what are the four CNS nuclei that can be found in the pons?
- trigeminal principal sensory nucleus
- trigeminal motor nucleus
- trigeminal spinal nucleus
- supratrigeminal nucleus (coordinates chewing)
what part of the brainstem has no CNS nuclei for CN V
medulla
concerning CN V, what is the responsibility of the supratrige minal nucleus and where can you find it?
- coordinate chewing
- just rostral to trigeminal motor nucleus
concerning CN V, there is an ascending projection from the trigeminal spinal nucleus that is ______ and projects to ______ _____ nucleus of thalamus, that ultimately ends in ____ ____
- CONTRALATERAL
- vetral posteromedial (VPM)
- brodmann’s area (3,1,2)
concerning CN V, there is an ascending projection from the main trigeminal sensory nucleus that is _____ and projects to _____ _____ nucleus of thalamus, that ultimately ends in ______ _____
- BILATERAL
- ventral posteromedial (VMP)
- brodmann’s area (3,1,2)
concerning CN V, the sensory afferents serve what 4 regions?
- face
- oral cavity
- teeth
- meninges
concerning CN V, where are the cell bodies for the sensory afferent?
trigeminal ganglion
concerning CN V, the sensory afferent fibers terminate in what nucleus?
main trigeminal sensory nucleus
concerning CN V, what senses are accounted for by the main trigeminal sensory nucleus?
- descriptive touch
- vibration
CN V sensory nucleus is a homologue of what?
posterior column nuclei
concerning CN V, the main sensory nucleus has both ____ and _____ ascending pathways
- crossed
- uncrossed
concerning CN V, the main sensory nucleus’ crossed ascending pathway joins the ____ ____ on its way to the _____
- medial lemniscus
- VPL
concerning CN V, the main sensory nucleus’ uncrossed pathway is called the ____ ____ ____ and deals with the ____ of the mouth represented to _____
- dorsal trigeminal tract
- inside
- VPM (ends newer uncrossed taste pathway)
concerning CN V, what senses are accounted for by the trigeminal spinal nucleus?
pain, crude touch, temperature
the spinal trigeminal nucleus is divided into what three parts?
- oral nucleus (most rostral)
- interpolar nucleus (middle)
- caudal nucleus (most caudal)
concerning CN V, what part of the spinal trigeminal nucleus receives input from intraoral and perioral structures?
pars oralis
concerning CN V, what part of the spinal trigeminal nucleus is concerned with activation of trigemina-autonomic reflexes?
pars interpolaris proper
concerning CN V, what part of the spinal trigeminal nucleus is not somatotopically organized and responds to pain stimuli from many areas? it also may be involved in activation of pain suppression mechanisms
caudalis-interpolaris transition zone
concerning CN V, part of the spinal trigeminal nucleus that deals with pain, crude touch, and temperature sensation and receives its information from superficial structures (oral cavity, teeth) and deep structures (jaw mm and TMJ)
pars caudalis
concerning CN V, in the spinal trigeminal nucleus, the afferents descend thru _____ ____ ____ and synapse in the _____ _____
- spinal trigeminal tract
- caudal nucleus
concerning CN V, in the spinal trigeminal nucleus, second order neurons send axons across the midline, ascend and join the _____ _____ to ultimately terminate in ______
- spinothalamic tract
- VPM
concerning CN V, the pars caudal is receives afferents from what three cranial nerves? all for an area near the _____
- VII, IX, and X
- ear
concerning pars caudalis, the pain-temperature afferents of the mandibular division are in the _____ end
dorsal
concerning pars caudalis, the pain-temperature afferents of the ophthalmic division are in the ____ end
ventral
concerning pars caudalis, the fibers representing the center of the face end near the _____
obex
concerning pars caudalis, the fibers representing the back of the face end in ____ ____ _____
upper cervical cord
the more ____ the spinal trigeminal injury, the larger the area around the mouth that is spared of sensory loss
caudal
concerning CN V, 70-80% of fibers from the tooth pulp are ______ (fast pain, thermal) and _____ (slow pain, itch, and touch)
- A delta
- C delta
concerning CN V, 20-30% of fibers from the tooth pulp are ____ (spindle, touch, and pressure)
[from inferior alveolar nerves, enter root canals and form plexus in pulp, predentin, and dental tubules]
A-beta
what are the 3 places that fibers from the tooth pulp project to?
- trigeminal main sensory nucleus (heaviest projection, shared)
- trigeminal spinal nucleus
- upper cervical spinal cord
fibers from the tooth pulp project to all three parts of the trigeminal spinal nucleus. what part is the heaviest projection, modest, and light?
pars oralis - heaviest projection
pars interpolaris - modest projection
pars caudalis - upper cervical spinal cord
70% of brief episodes of excruciating pain in the distribution of one (can be more) division of the trigeminal nerve occurs where?
mandibular division
<5% of brief episodes of excruciating pain in the distribution of one (can be more) division of the trigeminal nerve occurs where?
ophthalamic division
brief episodes of excruciating pain in the distribution of one (can be more) division of the trigeminal nerve
trigeminal neuralgia
concerning trigeminal neuralgia, there (is/is not) sensory trouble between attacks?
is not
concerning trigeminal neuralgia, often a _____ stimulus triggers an attack
tactile
concerning trigeminal neuralgia, a number of cases due to ____ _____ by a vessel, tumor etc
trigeminal compression
concerning trigeminal neuralgia, are medications helpful? is surgery?
- meds can help
- surgery has been known to be fatal
concerning trigeminal neuralgia, what is cut during surgery?
trigeminal ganglion
concerning trigeminal neuralgia, what is the result of cutting the trigeminal ganglion during surgery
loss of all tactile sensation (not just pain) to the area
beaches of the ____ ____ artery are most frequently involved in cases of trigeminal neuralgia that is due to vascular cause
superior cerebellar
nucleus that is concerned with the jaw jerk reflex
trigeminal motor nucleus
nucleus that is concerned with chewing movements
supratrigeminal nucleus
the trigeminal mesencephalic nucleus of CN V is involved with what three things?
- proprioception
- muscles of mastication
- mechanoreceptors in gums, teeth, and the hard palate
what are the two nuclei that the mesencephalic nucleus projects to?
- trigeminal motor nucleus
- supratrigeminal nucleus (masticatory generator)
concerning proprioception, the mesencephalic nucleus controls the ____ between the mandible and the maxilla
distance
concerning CN V, all of the nuclei involved all are heavily myelinated except _____
spinal nucleus (lightly myelinated)
the cell bodies of the trigeminal motor nucleus will terminate in the ____ ___ _____
mm of mastication
the supratrigeminal nucleus of a pattern generator for ____ _____
masticatory rhythm
the trigeminal motor nucleus innervates what 3 things?
- mm of mastication
- tensor tympani
- tensor palati
the trigeminal motor nucleus is the efferent limb of the ____ ____ ____
jaw jerk reflex
the jaw-jerk reflex is a ______ reflex that involves a downward tap on the chin which stretches the _____
- monosynaptic
- masseter
what is the afferent limb of the jaw-jerk reflex?
mesencephalic V neuron
what is the efferent limb of the jaw-jerk reflex?
V motor nucleus
like other reflexes, the jaw-jerk reflex is enhanced with ____ ____ ____ damage, and uses that to determine the level of injury
upper motor neuron damage
the ____ branches of the mesencephalic neurons innervate masseter muscle spindles and other mechanoreceptors
peripheral
the CNS origin for both the visceral and somatic fiber types of CN VII is the ____ _____
geniculate ganglion
concerning CN VII, the sensation of taste from anterior 2/3 of tongue, and parts of the nasal cavity and soft palate is considered ____ sensation
visceral
The CNS origin for the brachial motor division of CN VII that is concerned with muscles of mastication and stapedius, is the _____ ______ _____
facial motor nucleus
what are the 6 responsibilities of CN VII
- close eye/lip
- modulate sound volume (stapedius m)
- taste of anterior 2/3 tongue
- general sensation (palatine tonsil & posterior nasal cavity)
- salivation
- lacrimation (lubricate cornea)
the somatic sensory fibers of CN VII, enter the ____ ____ _____ dorsomedially situated and act exactly as ____ ____
- spinal trigeminal tract
- trigeminal afferents
the motor neurons to the lower facial mm are mainly innervated by the _____ _____ but upper facial mm are innervated _____
- contralateral cortex
- bilaterally
unilateral damage to corticobulbar pathway (ie in cerebral peduncle) results in the inability to _____ or bare _____ ______, but still have the ability to ____ ____
- smile
- teeth symmetrically
- wrinkle forehead
type of UNILATERAL facial paralysis due to the dysfunction of CN VII that is the MOST COMMON cause of acute facial nerve paralysis
Bell’s palsy
Bell’s palsy is believed to be an ____ condition resulting in facial nerve _____ in the ___ _____
- inflammatory
- swelling
- facial canal
bell’s palsy commonly shows ____ onset with partial or complete paralysis
rapid (can occur overnight)
concerning bell’s palsy, _____ can improve outcome and the function can be restored
steroids
_____ is a term used for bell’s palsy patients being very sensitive to sounds
hyperacusis
during bell’s palsy, the patient experiences reduced _____ and ____
- lacrimation
- salivaiton
what is the main way that bell’s palsy is different from a corticobulbar lesion?
bc bell’s palsy causes a paresis of facial mm ABOVE AND BELOW the eye
bell’s palsy cause irritation of the _____
cornea
during bell’s palsy, the eye on the affected side cannot be _____, resulting in permanent corneal damage
closed
reflex test that involves touching a cornea to see if both eyes blink
corneal blink reflex
why is the corneal blink test so important?
bc it can test both CN’s V and VII
afferent limb is V (sensory)
efferent limb is VII (closes the eye)
where is the first synapse in the blink to light reflex
superior colliculus
where is the 2nd synapse in the blink to light reflex
facial nucleus (closes the eye)
where is the first synapse in the blink to noise reflex?
inferior colliculus
where is the second synapse in the blink to noise reflex?
facial nucleus (closes the eye)
where is the first synapse in the sound attenuation reflex?
superior olivary nucleus (pons)
where is the second synapse in the sound attenuation reflex
facial nucleus
during taste, ___ receptors respond to ____ ____
- olfactory
- food vapors
number of taste buds in ppl is highly _____
variable
the nervus intermedius gives rise to ____ ____ nerve and ____ ____
- greater petrosal
- chorda tympani
regarding taste pathways in the CNS, the gustatory afferents reach nucleus of the solitary tract via the ____ ____
solitary tract
what two things do the second order fibers do regarding taste pathways?
- reflex activities (swallowing, salivation)
- project UNCROSSED to thalamus, then to gustatory cortex
regarding taste pathways, the gustatory cortex projects to _______ cortex, integrated there with _____ information, then reaches the ______, from there to _____ system and _____
- orbitofrontal cortex
- olfactory
- amygdala
- limbic system
- hypothalamus
nucleus of the solitary tract surrounds the ______
solitary tract (this is right)
the nucleus of the ____ ___ is the principal visceral sensory nucleus of the brainstem
solitary tract
