Cranial Nerves
What cranial nerve conveys somatosensory information from the face, eyes, and mouth and motor signals to the muscles of mastication?
Trigeminal nerve (CN V)
What cranial nerve is responsible for the movement of the jaw during speech?
Trigeminal nerve (CN V)
What is the worse pain someone can ever experience?
Trigeminal neuralgia
True or False: People with trigeminal neuralgia experience no loss of somatosensation.
True
True or False: Sensorineural deafness is less common than conductive deafness.
True
What visual field does the optic chiasm cross, nasal or temporal?
Information from the nasal field (the temporal field remains uncrossed)
3 Cranial Nerves Involved in the Coordination of Eye Movement
1. Oculomotor nerve (CN III) 2. Trochlear nerve (CN IV) 3. Abducens nerve (CN VI)
What form of tinnitus is considered normal?
Infrequent, mild, and high-pitched "ringing" that lasts for seconds to minutes particularly in quiet environments
5 Motor Cranial Nerves (Some Say Marry Money But My Brother Says Big Brains Matter Most)
1. Oculomotor nerve (CN III) 2. Trochlear nerve (CN IV) 3. Abducens nerve (CN VI) 4. Accessory nerve (CN XI) 5. Hypoglossal nerve (CN XII)
Vestibulocochlear Nerve (CN VIII)
Inner ear
5 Visual Reflexes
1. Accommodation 2. Corneal 3. Visual body 4. Pupillary 5. Light
What 2 nervous systems do the cranial nerves exchange information between?
1. Central nervous system 2. Peripheral nervous system
2 Divisions of Vestibular Ganglion
1. Cerebellum 2. Vestibular nuclei
What is deafness as a result of peripheral disorders classified as?
1. Conductive 2. Sensorineural
What 3 visual reflexes are typically done in the clinic?
1. Corneal reflex 2. Visual body 3. Pupillary reflex
2 Light Reflex Responses
1. Direct 2. Consensual
What 2 cranial nerves are affected in Ramsay Hunt Syndrome?
1. Facial nerve (CN VII) 2. Vestibulocochlear nerve (CN VIII)
What 2 cranial nerves are involved in the gag and swallowing reflex?
1. Glossopharyngeal nerve (CN IX) 2. Vagus nerve (CN X)
What 4 cranial nerves innervate the mouth, neck, and viscera?
1. Glossopharyngeal nerve (CN IX) 2. Vagus nerve (CN X) 3. Accessory nerve (CN XI) 4. Hypoglossal nerve (CN XII)
What can unilateral facial palsy result from?
1. Lesion of the facial nerve (CN VII) nucleus 2. Lesion of the axons of the facial nerve (CN VII)
What 2 eye movements are controlled by the trochlear nerve (CN IV)?
1. Looking down 2. Looking down and to the side
4 Nuclei of the Trigeminal Nerve (CN V)
1. Main sensory nucleus 2. Spinal nucleus 3. Mesencephalic nucleus 4. Motor nucleus
2 Nuclei of Oculomotor Nerve (CN III)
1. Motor 2. Parasympathetic
3 Facial Nerve Distributions
1. Motor 2. Parasympathetic 3. Sensory
4 Functions of Cranial Nerves
1. Motor innervation to muscles of the face, eyes, tongue, jaw, and two neck muscles 2. Transmit somatosensory information from the skin, muscles of the face, and the temporomandibular joint 3. Transmit special sensory information related to visual, auditory, vestibular, taste, olfactory, and visceral sensations 4. Provide parasympathetic regulation of pupil size, curvature of the lens of the eye, heart rate, blood pressure, breathing, and digestion
Where does the trochlear nerve (CN IV) originate?
Midbrain
What 10 cranial nerves are apart of the peripheral nervous system?
1. Oculomotor nerve (CN III) 2. Trochlear nerve (CN IV) 3. Trigeminal nerve (CN V) 4. Abducens nerve (CN VI) 5. Facial nerve (CN VII) 6. Vestibulocochlear nerve (CN VIII) 7. Glossopharyngeal nerve (CN IX) 8. Vagus nerve (CN X) 9. Accessory nerve (CN XI) 10. Hypoglossal nerve (CN XII)
2 Parts of the Olfactory System
1. Olfactory bulb 2. Olfactory tract
Where is information sent from the olfactory tract once the olfactory nerve divides (CHHAR)?
1. Olfactory cortex in temporal lobe 2. Hypothalamus 3. Hippocampus 4. Amygdala 5. Reticular formation
12 Cranial Nerves
1. Olfactory nerve (CN I) 2. Optic nerve (CN II) 3. Oculomotor nerve (CN III) 4. Trochlear nerve (CN IV) 5. Trigeminal nerve (CN V) 6. Abducens nerve (CN VI) 7. Facial nerve (CN VII) 8. Vestibulocochlear nerve (CN VIII) 9. Glossopharyngeal nerve (CN IX) 10. Vagus nerve (CN X) 11. Accessory nerve (CN XI) 12. Hypoglossal nerve (CN XII)
3 Sensory Cranial Nerves (Some Say Marry Money But My Brother Says Big Brains Matter Most)
1. Olfactory nerve (CN I) 2. Optic nerve (CN II) 3. Vestibulocochlear nerve (CN VIII)
What 2 cranial nerves are apart of the central nervous system?
1. Olfactory nerve (CN I) - convey olfactory information 2. Optic nerve (CN II) - convey visual information
3 Divisions of Trigeminal Nerve (CN V)
1. Ophthalmic 2. Maxillary 3. Mandibular
Optic Tract Pathway
1. Optic chiasm 2. Cerebral peduncle 3. Lateral geniculate nucleus 4. Thalamus 5. Primary visual cortex (optic radiation)
3 Stages of Swallowing
1. Oral 2. Pharyngeal and laryngeal 3. Esophageal
Optic Radiation Pathway
1. Primary visual cortex 2. Internal capsule 3. Terminate on visual cortex (brodmann's area 17)
3 Oculomotor Nerve (CN III) Reflexes
1. Pupillary 2. Accommodation 3. Convergence
What 3 functions do the cranial nerves serve?
1. Sensory 2. Motor 3. Autonomic
3 Classifications of Cranial Nerves
1. Sensory 2. Motor 3. Mixed
What 2 muscles does the accessory nerve (CN XI) innervate?
1. Sternocleidomastoid 2. Trapezius
What are the 2 parasympathetic nuclei of the facial nerve (CN VII)?
1. Superior salivatory nuclei 2. Lacrimal (tears) nuclei
4 Mixed Cranial Nerves (Some Say Marry Money But My Brother Says Big Brains Matter Most)
1. Trigeminal nerve (CN V) 2. Facial nerve (CN VII) 3. Glossopharyngeal nerve (CN IX) 4. Vagus nerve (CN X)
What 5 cranial nerves may be affected when a person frequently chokes, experiences a lack of awareness of food in one side of the mouth (pocketing), or food comes out of the nose?
1. Trigeminal nerve (CN V) 2. Facial nerve (CN VII) 3. Glossopharyngeal nerve (CN IX) 4. Vagus nerve (CN X) 5. Hypoglossal nerve (CN XII)
4 Cranial Nerves Possibly Involved in Dysarthria
1. Trigeminal nerve (CN V) 2. Facial nerve (CN VII) 3. Vagus nerve (CN X) 4. Hypoglossal nerve (CN XII)
In addition to the oculomotor nerve (CN III), what other cranial nerves are connected to the vestibulo-ocular reflex?
1. Trochlear nerve (CN IV) 2. Abducens nerve (CN VI) 3. Vestibulocochlear nerve (CN VIII)
2 Causes of Dysarthria
1. Upper motor neuron lesions or muscle dysfunction 2. Lower motor neuron involvement of cranial nerves
2 Branches of the Vestibulocochlear Nerve
1. Vestibular branch 2. Auditory branch
What are 2 rare causes of trigeminal neuralgia?
1. Viral neuritis 2. Tumors
How many pairs of cranial nerves are there?
12
How many neurons does the olfactory system have?
2
How many nuclei does the oculomotor nerve (CN III) have?
2
What percent of people with unilateral facial nerve paralysis have an identifiable cause and thus do not have Bell's Palsy?
32%
How many nuclei does the trigeminal nerve (CN V) have?
4
What is the most common ocular motor paralysis in adults and the second-most common in children?
Abducens nerve palsy
Abducens Nerve (CN VI) Test
Abduction Physiologic "H"
What may be preserved in the instance brain damage such as aphasia interferes with voluntary speech?
Ability of the memory system to produce emotionally charged words, such as profanity
Binocular Vision
Ability to focus the two eyes in a coordinated manner in order to see one image
What does the loss of hearing in one ear interfere with?
Ability to locate sounds; normally, the timing of input from each ear is compared with the location of the sounds in space
What cranial nerve is responsible for the motor innervation of the sternocleidomastoid and trapezius muscles?
Accessory nerve (CN XI)
What is the parasympathetic nuclei of the oculomotor nerve (CN III) involved in?
Accommodation reflex and pupillary constriction
Common Causes of Sensorineural Deafness
Acoustic trauma Ototoxic drugs Meniere's disease Acoustic neuroma
Ramsay Hunt Syndrome
Acute facial paralysis accompanied with ear pain and blisters on the external ear that may cause vestibular and hearing problems
Accommodation
Adjustment of the eye when viewing an object that is close
Ectopic Foci
An excitable group of cells that cause a premature heart beat outside the normally functioning SA node of the heart
What can lesions of the olfactory nerve (CN I) result in?
An inability to smell
What does complete severance of any branch of the trigeminal nerve (CN V) result in?
Anesthesia of the area supplied by the ophthalmic, maxillary, or mandibular branch
What precautions are taken for people with dysphagia?
Aspiration precautions
What does a complete lesion of the hypoglossal nerve (CN XII) cause?
Atrophy of the ipsilateral tongue
What information does the vestibulocochlear nerve (CN VIII) convey?
Auditory and vestibular information
Visual Body Reflex
Automatic scanning movements made with the eyes
What sensory information is the vestibular branch of the vestibulocochlear nerve (CN VIII) responsible for?
Balance and head position
Why do upper motor neuron lesions cause paresis rather than paralysis?
Because cortical innervation is bilateral and the muscles become hypertonic rather than hypotonic
Acoustic Neuroma
Benign tumor arising from the vestibulocochlear nerve (CN VIII) in the brain
What does the optic chiasm contribute to?
Binocular vision
What type of cells are in the olfactory bulbs?
Bipolar neurons
Corneal Reflex
Blinking of the eyelid with a touch of light on the cornea
Where does the trochlear nerve (CN IV) receive information from?
Both hemispheres
Where does the abducens nerve (CN VI) receive information from?
Both hemispheres Superior colliculus Visual cortex Longitudinal fasciculus
What is the activity of the hypoglossal nerve (CN XII) controlled by?
Both voluntary and reflexive neural circuits
Where do other fibers terminate?
Brodmann's areas 18 and 19
How can extreme emotions interfere with the ability to eat and speak?
By activating emotion pathways that influence motor activity
What is the vestibular ganglion of the vestibular branch of the vestibulocochlear nerve (CN VIII) connected to?
CN III, IV, and VI through medial longitudinal fasciculus Thalamus Vestibulospinal tract
What does a complete facial nerve (CN VII) lesion prevent?
Commands from reaching all ipsilateral facial muscles
Where is the accessory nerve (CN XI) located?
Cervical spine
What type of receptors are odor proteins?
Chemoreceptors
How can people with Bell's Palsy recover?
Chewing gum
What do clinicians believe Bell's Palsy could be due to?
Chicken pox or shingles
What does the auditory branch of the vestibulocochlear nerve (CN VIII) innervate?
Cochlea
Facial Nerve (CN VII) Lesion vs Corticobrainstem Tract Lesion
Complete facial nerve (CN VII) lesion prevents commands from reaching all ipsilateral facial muscles while a corticobrainstem tract lesion prevents voluntary control of the contralateral lower face
Which type of deafness is more common, conductive or sensorineural?
Conductive deafness
What is the olfactory cortex in the temporal lobe responsible for in the olfactory system?
Conscious perception of smell
Where is the spinal nucleus of the trigeminal nerve (CN V) located?
Continuous with main sensory nucleus, traveling down the length of the medulla
Masseter Reflex
Contraction of the masseter and temporalis muscles when a person's lower jaw is tapped
What is the oculomotor nerve (CN III) responsible for?
Coordination of eye and head movements and reflexes
What type of control does speaking require?
Cortical control
What are descending emotion pathways separate from?
Corticobrainstem tracts
What do upper motor neuron lesions cause?
Paresis and swallowing dysfunctions due to hypertonicity
What do problems with tongue control result in?
Difficulty speaking and swallowing
What does a complete lesion of the vagus nerve (CN X) cause?
Difficulty speaking and swallowing Poor digestion Asymmetrical elevation of the palate Hoarseness Loss of the gag and swallowing reflex
Dysphagia
Difficulty swallowing
Is the olfactory system directly or indirectly wired?
Directly wired
Meniere's Disease
Disorder of inner ear causing vertigo, tinnitus, and hearing loss
When does sensorineural deafness occur?
Due to damage of the receptor cells or the cochlear nerve
Trigeminal Neuralgia
Dysfunction of the trigeminal nerve (CN V) that produces severe, sharp, stabbing pain in the distribution of one or more branches
What parasympathetic gland of the glossopharyngeal nerve (CN IX) is involved in the gag and swallowing reflex?
Parotid (saliva) gland
What is the amygdala responsible for in the olfactory system?
Emotional responses associated with smell
What does the inability to blink cause as a result?
Excessive dry eyes since the eyes are staying open
Common Causes of Conductive Deafness
Excessive wax in the outer ear canal Otitis media
Optic Nerve (CN II)
Eye
Esotropia
Eye misalignment causing one eye to deviate inward
Oculomotor Nerve (CN III)
Eye muscles (superior, inferior, medial rectus, and inferior oblique)
What does the motor nuclei of the oculomotor nerve (CN III) raise?
Eyelids
What must be done to the eyelids to protect the eyes?
Eyelids must be sutured, taped shut, or covered with an eye patch
What do the cranial nerves supply motor innervation to?
Face Eyes Tongue Jaw Two neck muscles
What cranial nerve is responsible for the motor innervation of the muscles of facial expression, salivary glands, and taste receptors?
Facial nerve (CN VII)
What cranial nerve is responsible for the movement of the lips during speech?
Facial nerve (CN VII)
Voluntary vs. Emotion Control of Cranial Nerves
Fake smile (voluntary) vs. sincere smile (emotion pathways) Eye movements can be voluntarily controlled or the eyes may be automatically drawn toward or away from disturbing sights Speaking is mostly voluntary but can occur automatically in highly emotional contexts
How do cranial nerves differ from spinal nerves?
In specialization; some are only motor, others are only sensory, and some are both sensory and motor (mixed)
What does a complete lesion of the glossopharyngeal nerve (CN IX) interrupt?
Gag and swallowing reflex
Glossopharyngeal Nerve (CN IX) Test
Gag reflex
Vagus Nerve (CN X) Test
Gag reflex
Where does the optic nerve (CN II) begin?
Ganglionic layer of retina
What cranial nerve carries information from the tongue and larynx?
Glossopharyngeal nerve (CN IX)
What is the peripheral ending of the olfactory bulbs?
Hair cell
What structures do the cranial nerves innervate?
Head and neck
Where is the visual body reflex also evident?
Head and neck
Does the vestibular system or hearing tend not to recover with treatment of Ramsay Hunt Syndrome?
Hearing
What sensory information is the auditory branch of the vestibulocochlear nerve (CN VIII) responsible for?
Hearing
What cranial nerve is responsible for the motor innervation to the tongue?
Hypoglossal nerve (CN XII)
What cranial nerve is responsible for the movement of the tongue during speech?
Hypoglossal nerve (CN XII)
Where are the cell bodies of the hypoglossal nerve (CN XII) located?
Hypoglossal nucleus of the medulla
Where do the parasympathetic nuclei of the facial nerve (CN VII) receive information from?
Hypothalamus
Olfactory Nerve (CN I) Test
Identify odors
Bell's Palsy
Idiopathic paralysis of the facial nerves (CN VII) axons that causes muscular weakness in one side of the face resulting in facial droop and numbness
Where is the vagus nerve (CN X) located?
Inferior aspect of brain in medulla
Otitis Media
Inflammation of the middle ear
Where is the vestibular ganglion of the vestibular branch of the vestibulocochlear nerve (CN VIII) located?
Internal acoustic meatus
What does complete severance of the ophthalmic branch of the trigeminal nerve (CN V) result in?
Interruption of the blink reflex preventing blinking in response to a touch stimulation of the cornea
Hypoglossal Nerve (CN XII)
Intrinsic and extrinsic muscles of the tongue
What is the vagus nerve (CN X) responsible for in the parasympathetic nervous system?
Involuntary muscles of: Esophagus Stomach Small intestine Heart Bronchi
Does the hypoglossal nerve (CN XII) provide innervation to the intrinsic and extrinsic muscles of the ipsilateral or contralateral tongue?
Ipsilateral
Direct Wired
It does not travel through the thalamus but instead travels directly to where it needs to go
Abducens Nerve (CN VI)
Lateral rectus muscle (lateral eye movement including left to right and diagonal)
What does damage to the oculomotor nerve (CN III) cause?
Lateral strabismus diplopia
What are people with a corticobrainstem tract lesion able to do?
Laugh, cry, and close both eyes normally
How long does trigeminal neuralgia pain last?
Less than 2 minutes
In most trigeminal neuralgia cases what does the pressure of a blood vessel on the trigeminal nerve (CN V) cause?
Local demyelination and ectopic foci that sensitize the trigeminal nerve root and the trigeminal nerve nucleus
Do upper or lower motor neuron lesions cause muscle hypotonicity (less tone)?
Lower motor neuron lesions
Are cranial nerves primarily upper or lower motor neurons?
Lower motor neurons
Treatment of Tinnitus
Masking sounds provided by a hearing aid Medication Habituation techniques Transcranial magnetic stimulation of central auditory system
What reflex does the mandibular branch of the trigeminal nerve (CN V) control?
Masseter reflex
What type of receptors are hair cells?
Mechanoreceptors
What are the oculomotor nerve (CN III), trochlear nerve (CN IV), and abducens nerve (CN VI) connected through?
Medial longitudinal fasciculus
Where does the trochlear nerve (CN IV) also receive information from?
Medial longitudinal fasciculus (CN III, CN VI, and CN VIII)
How are the trochlear nerve (CN IV), abducens nerve (CN VI), and vestibulocochlear nerve (CN VIII) connected to the vestibulo-ocular reflex?
Medial longitudinal fasciculus and accessory parasympathetic nucleus
What does damage to the trochlear nerve (CN IV) cause?
Medial strabismus
What may tinnitus be caused by?
Medications Stimulation of receptors in the ear Central sensitization after deafferentation
What is the hippocampus responsible for in the olfactory system?
Memories associated with smell
What are the main motor muscles of the facial nerve (CN VII)?
Muscles for facial expression; auricular muscles, stapedius, digastric, and stylohyoid
What does the motor nuclei of the oculomotor nerve (CN III) control?
Muscles of the eye
Olfactory Nerve (CN I)
Nose
What is the optic radiation primarily involved in?
Object recognition and color perception (Ex: Yellow bus)
What proteins bind to the hair cells at the end of the olfactory bulbs?
Odor proteins
What is the oval structure with several cell type arrangements in the olfactory system called?
Olfactory bulb
Where is the olfactory nerve (CN I) located?
Olfactory mucosa of nasal cavities
What glial cell is the optic nerve (CN II) myelinated by?
Oligodendrocytes (CNS)
Where does the tractus solitarius of the facial nerve (CN VII) send information to?
Opposite side of: Thalamus Hypothalamus Primary sensory cortex
Where do the optic nerves from each eye cross?
Optic chiasm
What is the convergence section on the retina where the optic nerve is located?
Optic disc
Where is the optic nerve (CN II) located?
Optic disc of the retina
Which cranial nerve is an upper motor neuron?
Optic nerve (CN II)
When does trigeminal neuralgia pain begin and end?
Pain begins and ends abruptly
What sensory information does the trigeminal nerve (CN V) detect on the face?
Pain, touch, pressure, and temperature
What does a lesion of the facial nerve (CN VII) cause?
Paralysis of the ipsilateral muscles of facial expression Incomplete closure of the ipsilateral eye
What does a complete lesion of the accessory nerve (CN XI) cause?
Paralysis of the ipsilateral sternocleidomastoid and trapezius muscles
What stage of swallowing is commonly affected in dysphagia?
Pharyngeal stage
Trochlear Nerve (CN IV) Test
Physiologic "H"
Oculomotor Nerve (CN III) Test
Physiologic "H" Near point response
Where is the motor nucleus of the trigeminal nerve (CN V) located?
Pons
Where is the cochlear nuclei of the auditory branch of the vestibulocochlear nerve (CN VIII) located?
Pons/medulla junction
Dysarthria
Poor control of speech muscles
Where is the main sensory nucleus of the trigeminal nerve (CN V) located?
Posterior pons
Where do other fibers of the optic tract go?
Pretectal nucleus and superior colliculus
What type of motor information does the trigeminal nerve (CN V) detect for the muscles of mastication?
Proprioceptive information
Direct Light Reflex
Pupil constriction of the eye with light
Consensual Light Reflex
Pupil constriction of the eye without light
Pupillary Reflex
Pupil constricts when light is shined into eye
What parasympathetic regulation do the cranial nerves provide?
Pupil size Curvature of the lens of the eye Heart rate Blood pressure Breathing Digestion
PERRLA
Pupils are Equal Round Reactive to Light Accommodation
What happens to the eye during accommodation?
Pupils constrict Lens becomes more convex Eyes converge
What is the onset of Bell's Palsy?
Rapid onset between minutes to days
What can people with dysarthria do?
Read and write
Abducens Nerve Palsy
Results in esotropia due to the unopposed action of the antagonistic medial rectus muscle of the eye causing the eye to deviate medially
Vestibulocochlear Nerve (CN VIII) Test
Rinne test for hearing Weber test for balance
What is decreased as a result of a complete lesion of the glossopharyngeal nerve (CN IX)?
Salivation (dry mouth)
What does the vestibular branch of the vestibulocochlear nerve (CN VIII) innervate?
Semicircular canals, utricle, and saccule
What visceral information does the glossopharyngeal nerve (CN IX) detect?
Taste from tongue Blood pressure Chemicals from carotid arteries
Through what tract does the trochlear nerve (CN IV) receive information from both hemispheres?
Tectobulbar tract
In what lobe of the brain is the olfactory cortex located in?
Temporal lobe
Glossopharyngeal Nerve (CN IX)
Sensory: Back of tongue, middle ear, ear canal, and pharynx Motor: Pharyngeal musculature
Trigeminal Nerve (CN V) Test
Sensory: Clench jaw/palpate and light touch Motor: Corneal reflex
Trigeminal Nerve (CN V)
Sensory: Face, head, cornea, and inside of mouth Motor: Muscles of mastication (temporalis and masseter)
Vagus Nerve (CN X)
Sensory: Pharynx, larynx, external ear, thorax and abdomen viscera Motor: Pharynx and larynx
Facial Nerve (CN VII)
Sensory: Taste Motor: Facial expression (smile), eyelid closing, and stapes of ear
Accessory Nerve (CN XI) Test
Shrug Turn head against resistance
What do the cranial nerves transmit somatosensory information from?
Skin Muscles of the face Temporomandibular joint
Facial Nerve (CN VII) Test
Smile Puff cheeks Wrinkle forehead Open and close eyelids
What may also interfere with the function of the olfactory nerve (CN I)?
Smoking or excessive nasal mucus
What can a lesion to the trigeminal nerve (CN V), facial nerve (CN VII), vagus nerve (CN X), and hypoglossal nerve (CN XII) affect?
Speaking
Where does the accessory nerve (CN XI) originate?
Spinal accessory nucleus in the upper cervical cord
What can people with dysarthria understand?
Spoken language
Accessory Nerve (CN XI)
Sternocleidomastoid and trapezius muscle (head movement)
What can damage to the abducens nerve (CN VI) cause?
Strabismus Nystagmus
How is the tectobulbar tract connected to the visual cortex?
Superior colliculus
Trochlear Nerve (CN IV)
Superior oblique muscle
What is the cochlear nuclei of the auditory branch of the vestibulocochlear nerve (CN VIII) connected to?
Superior olive Midbrain at inferior colliculus Thalamus Auditory cortex through internal capsule (acoustic radiation)
What are the bipolar neurons in the olfactory bulbs positioned with?
Supporting cells
What may both Bell's Palsy and Ramsay Hunt Syndrome cause?
Synkinesis
Transcranial Magnetic Stimulation
Treatment that involves placing a powerful pulsed magnet over a person's scalp to alter neuronal activity in the brain
Light Reflex
The constriction of both eye pupils when light is shined into one eye
What does complete severance of the mandibular branch of the trigeminal nerve (CN V) result in?
The jaw will deviate toward the involved side when the mouth is opened (side talk)
How is the olfactory system different than other sensory systems?
The olfactory system only has two neurons where other systems have three and it is directly wired
What happens when a person with a hypoglossal nerve (CN XII) lesion is asked to stick out their tongue?
The tongue will protrude ipsilaterally (toward the side of the lesion) rather than in the midline
How do the parasympathetic nuclei of the facial nerve (CN VII) send information?
Through autonomic system pathways
Where does the accessory nerve (CN XI) travel upward?
Through the foramen magnum
Where does the accessory nerve (CN XI) leave the skull?
Through the jugular foramen
Hypoglossal Nerve (CN XII) Test
Tongue deviation
What sensory tract of the facial nerve (CN VII) receives sensations of taste?
Tractus solitarius
Synkinesis
Unintended movements that occur when regenerative sprouting causes a neuron to contact the incorrect muscle
Where is the mesencephalic nucleus of the trigeminal nerve (CN V) located?
Unipolar nerves in gray matter around cerebral aqueduct
Do upper or lower motor neuron lesions cause muscle hypertonicity (more tone)?
Upper motor neuron lesions
What cranial nerve also innervates thoracic and abdominal viscera?
Vagus nerve (CN X)
What cranial nerve conveys somatosensory information from the external part of the ear and from the pharynx and larynx?
Vagus nerve (CN X)
What cranial nerve is responsible for the articulation of sound by the soft palate?
Vagus nerve (CN X)
What cranial nerve is responsible for the motor innervation to the palate, pharynx, larynx, and heart; and is both afferent and efferent for the thoracic and abdominal viscera and for digestive tract glands?
Vagus nerve (CN X)
What cranial nerve is responsible for the sound generated by the larynx?
Vagus nerve (CN X)
What is Ramsay Hunt Syndrome caused by?
Varicella zoster (chicken pox/shingles) infection
Where are the cell bodies of the accessory nerve (CN XI) located?
Ventral horn at levels C1 to C4 (this helps clinicians know that people with C4 spinal cord injuries can still move their heads)
What reflex does the motor nuclei of the oculomotor nerve (CN III) assist with?
Vestibulo-ocular reflex
What is the reticular formation responsible for in the olfactory system?
Visceral responses associated with smell
What special sensory information do the cranial nerves transmit?
Visual Auditory Vestibular Taste Olfactory Visceral
Optic Nerve (CN II) Test
Visual acuity Visual fields Identify colors
Functions of Optic Nerve (CN II)
Visual acuity Visual reflexes
What is the tectobulbar tract connected to?
Visual cortex
What type of speech is affected in dysarthria?
Vocal speech (people can speak but it is incomprehensible)
What do cortiocobrainstem tract lesions prevent?
Voluntary control of the contralateral lower face
When does conductive deafness occur?
When the transmission of vibrations is prevented in the outer or middle ear
How does the vestibular system recover with treatment of Ramsay Hunt Syndrome?
With early treatment of corticosteroids and antiviral drugs
