Cranial nerves Flashcards
How many pairs of cranial nerves are there
12
Olfactory nerve is the only sensory modality that does not synapse in the thalamus, true or false
true
Where is the primary olfactory cortex
temporal lobe
What sensory neurons pick sense olfaction
bipolar neurons
What type of nuclei are motor components associated with
motor nuclei
What type of nuclei are sensory components associated with
sensory nuclei
Where are the nuclei of CN 3, 4, 6 and 12 found
midline
Oculomotor nerve: what is the nucleus for the somatic motor modality
nucleus of oculomotor nerve
Oculomotor nerve: what is the nucleus for parasympathetics
Edinger-Westphal EW nucleus
Where are the CN 3 nuclei found
superior colliculus in midbrain
What is the nucleus for the trochlear nerve - somatic motor
nucleus of trochlear nerve
Where is the nucleus of trochlear nerve found
inferior colliculus in midbrain
what nuclei are associated with the trigeminal nerve
mesencephalic nucleus
principle sensory nucleus
spinal nucleus
motor nucleus of CN V
Where are the trigeminal nuclei found
pons
What nucleus is associated with the abducens nerve - somatic motor
nucleus of abducent nerve
Where is the CN VI nucleus found
pons
What is the nucleus associated with the hypoglossal nerve
nucleus of the hypoglossal nerve
where is the nucleus of the hypoglossal nerve found
medulla
What are the nuclei for the facial nerve:
motor
sensory
parasympathetic
motor = nucleus of facial nerve sensory = geniculuate nucleus/solitary tract parasympathetic = superior salivatory nucleus
What are the nuclei for the glossopharyngeal nerve: sensory special sensory - taste parasympathetic motor
sensory = spinal trigeminal nucleus taste = solitary tract nucleus parasympathetic = inferior salivatory nucleus motor = nucleus ambiguus
What are the nuclei of the vagus nerve: sensory taste (epiglottis - negligible) parasympathetic motor
sensory = spinal trigeminal nucleus taste = solitary tract nucleus parasympathetic = dorsal motor nucleus motor = nucleus ambiguus
Which cranial nerves share the solitary tract nucleus and what is the main function and where is it found
CN VII, IX, X
Taste
Medulla
Which cranial nerves share the nucleus ambiguus and where is it found
CN IX + X
Medulla
Which cranial nerves share the salivatory nuclei
facial (superior)
glossopharyngeal (inferior)
Sensory modalities of which cranial nerves share the spinal trigeminal nucleus
trigeminal
glossopharyngeal
vagus
What is meant by brain death
irreversible cessation of brainstem function
What is the corticobulbar tract
part of the pyramidal/descending tract that is motor output for cranial nerves 5, 7, 10, 12
ie regulation of brainstem activity
input to the corticobulbar tract is bilateral, what is the exception
input to the facial nucleus is only bilateral to muscles that control the upper face only
What is the input for parasympathetic CN 3, 7, 9, 10
hypothalamus
What is the reticular formation
network of loosely aggregated cells in the central core of the brainstem
What are the functions of the reticular formation
integrate CN reflexes conduction and modulation of pain voluntary movement autonomic activity respiration sleep maintains consciousness
What is the pathway of the olfactory nerve
olfactory mucosa in nasal cavity
cribriform plate of ethmoid bone
olfactory bulb
cerebral cortex
What is the pathway of the oculomotor nerve
midbrain
lateral to cavernous sinus
superior orbital fissure
orbit + ciliary ganglion
What is the pathway of the trochlear nerve
midbrain
lateral wall of cavernous sinus
superior orbital fissure
superior oblique muscle
What is the pathway of the abducent nerve
pontomedullary junction
WITHIN the cavernous sinus
superior orbital fissure
Lateral rectus muscle
Which cranial nerve travels within the cavernous sinus
CN VI
What is the pathway of the vestibulocochlear nerve
cochlear and vestibular apparatus
internal acoustic meatus
towards PMJ
pontomedullary junction
What is the pathway of the spinal accessory nerve
cervical spinal cord
enters foramen magnum
exits jugular foramen
supplies sternocleidomastoid and trapezius
What is the pathway of the hypoglossal nerve
medulla oblongata
anterior to hypoglossal canal
hypoglossal canal
descends lateral to the carotid sheath and goes to supply the tongue at the level of the hyoid bone
Which extrinsic muscle of the tongue does CN XII NOT supply
palatoglossus - supplied by CN X
Where in the brainstem does CN V originate
pons
travels inferior to the tentorium cerebelli
What are the cranial formainae for
CN V1
CN V2
CN V3
- superior orbital fissure
- foramen rotundum
- foramen ovale
What is the pathway of the facial nerve
pontomedullary junction
internal acoustic meatus
muscles of facial expression, submandibular and sublingual salivary glands
What supplies taste to anterior 2/3rds of tongue
chorda tympani of facial nerve
In Bells palsy, is taste preserved?
yes, taste is still fine because chorda tympani has already branched off
Through which foramen does the facial nerve exit the skull
stylomastoid foramen
What is the pathway of the glossopharyngeal nerve
medulla oblongata
jugular foramen
descends towards pharynx and mouth
Which salivary gland does CN IX innervate
parotid gland
What is the pathway of the vagus nerve
medulla oblongata
jugular foramen
descends in carotid sheath, supplies from palate to midgut, gives of RLN branches
Auditory pathway is bilateral, true or false
true
Describe the auditory pathway (ECOLI)
Eighth cranial nerve Cochlear nuclei (pons) superior Olivary nucleus (pons) Lateral lemniscus Inferior colliculus (midbrain) medial geniculate body thalamus auditory cortex
What is the lateral lemniscus in the auditory pathway
band of white matter carrying auditory information
What is the trapezoid body in the auditory pathway
carries information from the cochlear nucleus in the pons on one side of the body to the superior olivary nucleus on the other side
Where is the primary auditory cortex
temporal lobe
Tonotopic organisation is present in the auditory cortex, true or false
true
Where is Broca’s area found
left cerebral hemisphere in the frontal lobe
Where is Wernicke’s area found
left cerebral hemisphere in the temporal lobe
Damage to the Broca’s area results in what
Broca’s/expressive aphasia
difficulty in speech production
language comprehension is in tact
Damage to the Wernicke’s area results in what
Wernicke’s/receptive aphasia
difficulty in language comprehension
speech production is in tact
where do the 4 vestibular nuclei connect to
thalamus
medial longitudinal fasciculus + CN 3,4,6 nuclei
cerebellum
spinal cord
What is the medial longitudinal fasciculus
tract in brainstem which coordinates eye movements with head and neck movements
Where is the highest level of visual acuity found in the retina
fovea centralis in the macula
medial geniculate nucleus
auditory or visual
auditory
lateral geniculate nucleus
auditory or visual
visual
Describe the visual pathway
visual fields retinal fields optic nerves optic chiasm optic tracts (superior colliculi for reflexes) lateral geniculate nucleus in the thalamus optic radiations primary visual cortex in the calcarine sulcus of the occipital lobe
The lower visual field is projected to the gyrus superior/inferior to the calcarine sulcus
superior
The upper visual field is projected to the gyrus superior/inferior to the calcarine sulcus
inferior
What are optic radiations also known as
geniculocalcarine tracts
What is Meyer’s loop
fibres of the optic radiations that are part of the internal capsule that come from the upper visual field / lower retinal fields which loop around the temporal part of the lateral ventricles ending below the calcarine sulcus
fibres from upper/lower visual fields are found in Meyer’s loop
upper visual fields
lower retinal fields
what movements does the visual cortex (occipital lobe) provide
movements in response to visual stimuli eg tracking moving objects
smooth eye movement
what movements do the frontal eye fields control
movements of command ie independent of moving visual stimuli
jerky eye movements
Where are frontal eye fields found
motor cortex
What are the visual reflexes
pupillary light reflex
accommodation reflex
What does the pupillary light reflex look for
direct and consensual pupillary constriction
unilateral stimulus provides a bilateral response
What nerves are involved in the pupillary light reflex
optic nerve = afferent
oculomotor nerve = efferent
What is the accommodation reflex
looks for convergence, pupillary constriction and ciliary muscle contraction
tests CN III - EW nucleus
List some white matter tracts of the brain
association fibres
commissural fibres
projection fibres
What are association fibres
connect cortical sites lying in the same cerebral hemisphere
What are commissural fibres
connect one cerebral hemisphere with the other - usually those with similar functions
What are projection fibres
fibres that connect cerebral hemispheres to deeper structures eg thalamus, corpus striatum, brainstem and spinal cord
