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353 Cards in this Set

  • Front
  • Back
describe the function and location of pyramids
between the anterior median fissure and anterolateral sulcus.
describe the function and location of facial colliculus
location of the abducens nucleus (CN VI) structure of the pons
function and location of the tectum
structure of the midbrain on dorsal surface. superior colliculi- part of visual pathway. inferior colliculi- part of auditory pathway
substantia nigra
destruction leads to...
synthesize the neuro-transmitter dopamine. strong connection with putamen and caudate nucleus. destruction of dopamine-synthesizing cells leads to parkinson's disease. level of midbrain
list the cranial nerves emerging from teh following structures Midbrain? Pons? Medulla?
Midbrain: CNIII, CNIV


where does the spinal cord extend from
foramen magnum
the spinal cord is continuous with the
the spinal cord is anatomically segmented into how many segments
31 segments- paris of spinal nerves
what are the segments?
8 cervical
12 thoraic
5 lumbar
5 sacral
1 coccygeal
is the spinal cord shorter or longer than the vertebral canal?
the spinal cord goes down to which vertebral column
what is the filament that courses through from L1-S2
cauda equina (horse tail- what it can look like)

(in the lumbar cistern)
what is found in the filament
collection of Dorsal (sensory) and ventral (motor) roots
what are the names of the 2 enlargements of the spinal cord
1. cervical enlargement
2. lumbar enlargement
cervical enlargement extends from what to what? what does it contain?
extends from C5-T1

contains motor neurons supplying upper extremities
Lumbar enlargement extends from? contains?
extends from L2- S3

Contains motor neurons supplying lower extremities
the SC contains dorsal rootlets which carry what? and enter where?
dorsal rootlets carry sensory information from body to SC.

Dorsal rootlets enter SC posteriorly through posterolateral sulcus
Dorsal root ganglion is a collection of what? located where?
collection of cell bodies of primary sensory neurons.

located proximal to the junctio b/t dorsal and ventral roots.
ventral rootlets carry what? exit where?
carry motor information from the SC to muscles.

exit SC anteriorly through anterolateral sulcus
Dorsal and ventral rootlets join together to form what?
dorsal and ventral roots
dorsal and ventral roots becomes
join to form spinal nerves
what kind of fibers make up the spinal nerves?
afferent an efferent
the meningeal coverings of the spinal cord- 3 layers?
dura mater
pia mater
dura mater: how many layers?
single layered
arachnoid is closely attached to the?
the spinal dural sheath and arachnoid ends at?
spinal cord ends at?
the lumbar cistern is between?
L1-L2 and S2
is the pia mater thin or thick
the pia mater gives rise to the....which does what?
dentate ligament which anchors the SC to the arachnoid and dura (meningeal layers)
spinal cord segments are related systematically to...
areas of skin and muscles
each spinal nerve innervates what?
a single dermatome
knowledge of a segmental innervation is very helpful in what
diagnosing the site of damage in or near the SC
Functions of the Spinal Cord:
Sensory processing:
-afferent fibers enter what?
-terminate where?
afferent fibers enter the SC via the dorsal roots

terminate on the ipsilateral side of the CNS
controlling motor outflow:
motor neurons innervating skeletal muscle descend from?
the precentral cortex down to the SC- to motor neurons in the anterior horns
Controlling Motor outflow:
-motor neurons innervating skeletal muscle descend....
from precentral cortex down to the SC- to motor neurons in the anterior horns
axons of the motor neurons exit ....
through the ventral roots
Certain sensory inputs cause..
stereotyped motor outputs
many of these involve...
neural circuitry wholly contained within the SC
internal structure of the Spinal Cord (white matter):

- gray matter(inside) divided into...
horns (anterior and posterior)
white matter(outside) divided into?
funiculi (tracts)
what is the name of the fissure found in the internal structure of the SC
anterior median fissure (most obvious)
what are the 3 sulci found in the internal structures of the SC
1. posterior median sulcus
2. posterolateral sulcus
3. anterolateral sulcus
posterolateral sulcus is...
where dorsal roolets enter the SC
anterolateral sulcus is ...
where ventral rootlets exit the SC
posterior horn consists of
interneurons and projection neurons that collect into ascending sensory pathways
the interneurson...
connect neurons
the projection neurons...
travel long distance
where is substantia gelatinosa found?
in the posterior horn of SC
where exactly is it located? deals with?
located at the tip of the gray matter. deals with sensory fibers that carry pain and temperature info
the anterior horn contains?
cell bodies of large motor neurons that supply skeletal muscle
the lower motor neurons are also called the
alpha motor neurons
the lower motor neurons allows...
muscle contraction
destruction or interruption of lower motor neurons...
complete paralysis of invovled muscles
intermediate gray matter contains...(3)
various projection neurons, sensory interneurons, and interneurons that synapse on motor neurons
Clarke's nucleus is a collection of? important....nucleus for the ....?
also involved in?
-collection of large cells from T1 to L2
-inportant relay nucleus for the transmission of information to the cerebellum
- also involved in forwarding propioceptive information from the leg to the thalamus
ascending tracts carry what kind of information
sensory info
the posterior column- medial lemniscus system: organization:
contains cell bodies of...
spinal afferent fibers in ipsilateral dorsal root gangla
when entering the SC, dorsal rootlets...
segregates into a medial and lateral division
which fibers enter the posterior column
medial division
caudal to T6, each posterior column is an undivided bundle called
fasciculus gracilis
the fasciculus gracilis contains..
sensory information fromt he lower body/ limb
afferents entering rostral to T6 accumulate in a second bundle called...
fasciculus cuneatus
the fasciculus cuneatus contains...
sensory information from the upper body/ limbs-
somatotopic organization
this sort of arrangement in which particular portions of the body are represented in particular regions of a pathway or nucleus
Synapse in nucleus gracilis or nucleus cuneatus in the
caudal medulla
second -order fibers arising in the nuclei cross the midline and form the
medial lemniscus
the medial lemniscus terminates in the
thalamus (ventral posteriolateral nucleus, VPL)- nucleus that receives a lot of sensory info
third-order fibers ascend thru...
the internal capsule to synapse in the post central gyrus
the posterior column-medial lemniscus system carries info of...
touch, pressure, vibration and joint position and movement
damage causes ...
impairment of tactile sensitivity
more sever impairment in...
complex discrimination than in simple stimulus detection ( know something touched you, don't know pattern)
loss of...particularly when....
proprioception and kinesthesia- ataxia

particularly when eyes are closed
the Spinothalamic Tract: Course

invovled in ..
the awareness and localization of painful stimuli
the spinothalamic tract begins in ...
the dorsal root ganglion
the spinothatlamic tract enters the sc and sends...
axons to synapse at substantia gelatinosa (in the posterior horn)
the second-third-order cells send...
axons across the midline (ie. decussation at the level of the SC)
the spinothalamic tract travels up the
anterior part of the lateral funiculus
it synapses on
nuclei of the thalamus (VPL (ventroposterior lateral)- relays sensory info
travels up to the
postcentral gyrus
THe spinothalamic tract carries info on...(5)
itch sensation
pressure sensation from bladder and bowel
sexual sensation
destruction produces..
contralateral analgesia (deadening of the sense of pain)
The Posterior Spinocerebellar Tract is formed by
collaterals of posterior column fibers
the posterior spinocerebellar tract synapses on
neurons of Clarke's nucleus (in posterior horn of SC)
fibers project..
ipsilaterally to cerebellum through the inferior cerebellar peduncle
the posterior spinocerebellar tract carries info about..
tactile, pressure and proprioceptive
the posterior spinocerebellar tract is primarily concerned with
the ipsilateral leg
the anterior spinocerebellar tract is concerned with
the leg
2 differences from the posterior spinocerebellar tract
1. receives more complex inputs from a variety of sources- activity of the tract nerons related more to attempted movement (that you think about) than simple sensory signals

2.. the tract decussates at the level of the SC-ascends to the level of rostral pons- enters the cerebellum via the superior cerebellar peduncle- decussates again before ending in the vermis (untimately, ipsilateral control)
3 Major functions of the Brainstem
1. conduit function
2. cranial nerve function
3. integrative function
conduit function-
-primary means for...
-another characteristic?
1. primary means for connecting information from the cortex to the SC
2. relay station for several systems
cranial nerve function..which cranial nerves emerge from the brain stem? what is found in the brainstem?
cranial nerves III through XII project to or emerge from the brainstem

various sensory and motor nuclei related to cranial nerve functions found in the brainstem
integrative function
-what organizes at the level of the brainstem?
- much of this is accomplished by the...
some integrative functions organized at the level of hte brainstem

much of this accomplished by the reticular formation
what are the 2 structures on the ventral surface of the medulla
1. pyramids
2. olive
where are the pyramids found? what is it?
found b/t anterior median fissure and anterolateral sulcus

major motor pathway
what are two other names for Olive? what is Olive? (2)
also called inferior olives or inferior olivary nucleus

an oval swelling lateral to the anterolateral sulcus

relay nuclei for proprioception going into the cerebellum
what are the 2 structures of the Pons
1. facial colliculus
2. tegmentum
facial colliculus is the location of the...

what loops over the facial colliculus
location of the abducens nucleus (CN VI)

facial nerve fibers loop over it
tegmentum is way for....

what portion of the pons is the tegmentum

what does the tegmentum contain?
way for fibers to travel in brainstem

dorsal portion of pons

- ascending/descending tracts
- nuclei for CNV, VI, VII, VIII
what are the 3 structures of the midbrain
1. cerebral aqueduct
2. tectum
3. tegmentum
what part of the midbrain is the cerebral aqueduct
in the center
tectum is found on what surface of the midbrain?
dorsal surface
what are the two divisions of tectum?
superior colliculi- part of visual pathway

inferior colliculi-part of auditory pathway
tegmentum is the dorsal part of what? what does the tegmentum contain?
dorsal part of the cerbral peduncles

-contains important nuclei and nerve tracts
-contains nuclei of CNIII (oculomotor) and IV( trochlear)
what are the three deep structures of the brainstem?
1. red nucleus
2. subantia nigra
3. reticular formation
red nucleus (paired)
- important strutures in...
receive fibers from the contralateral cerebellum

imp structures in the motor system
substantia nigra is at the level of
the subantia nigra has strong connection to...
basal ganglia, putamen and caudate nuclesu
subantia nigra synthesize...
the neurotransmitter dopamine
destruction of dopamine- synthesizing cells results in
parkinsonism (motor disorder)
the reticular formation has..
multiple function
the reticular formation...
-participates in...
- modulates .....
- involved in control of....
participates in the control of movement

modulates the transimission of information in pain pathways

involved in the control of arousal and consciousness
functional Components of Cranial Nerves:

Bothin the spinal and cranial nerves: list 4 types of fibers.
1. somatic sensory fibers
2. visceral sensory fibers
3. visceral motor fibers
4. somatic motor fibers
somatic sensory fibers convey info from....

convey info concerning...
convey info from receptors in somatic structures of the head (e.g., skin, muscles, joints)

convey info concerning pain, temperature and mechanical stimuli
visceral sensory fibers convey info from
receptors in visceral structures (eg. glands, smooth muscles of the digestive tract, taste buds)
visceral motor fibers provide input to
smooth muscles and glands (heart)
somatic motor fibers innervate..
skeletal muscles (asons, extraocular and tongue muscles)
FUnctional Components of Cranial Nerves: Only in Cranial Nerves: list 2 types of fibers
1. Special sensory fibers
2. Branchiomeric Nerves
special sensory fibers are related to...

related to the special senses of hearing and equilibrium (CN VIII)

Innervates the muscles of the inner ear
Branchiomeric nerves innervate...
striated muscles of bronchial arch origin
examples of muscles innervated by brainchiomeric nerves
larynx, pharynx, jaw, face, middle ear muscles, sternocleidomastoid, trapezius
neurons for these muscles have...
a distinctive location in the brainstem
general location of CN Nuclei related to sulcus limitans1
1. motor nuclei medial to the sulcus limitans
2. sensory muclei later to the sulcus limitans
3. visceral nuclei located nearer the sulcus limitans
Three Types of Cranial Nerves: list
1. somatic motor nerves
2. special sensory nerves
3. Branchiomeric Nerves
Somatic motor nerves primarily contain...

which cranial nerves?
primarily contain motor axons for ordinary skeletal muscles

Special Sensory Nerves primarily contain

which nerves?
speical sensory fibers

Branchiomeric nerves typically contain....

all innervate...

which nerves?
contain several components

all innerave branchial arch musculature (facial area)

what is the name of cranial nerve 3
Oculomotor nerve
where is the motor nucleus for CNIII located and what is it called?
Oculomotor nucleus- located in midbrain
what does the CNIII supply
the somatic motor component of several muscles
what are the 5 muscles supplied by the CNIII
1. levator palpebrae superioris
2. superior rectus
3. medial rectus
4. inferior rectus
5. inferior oblique
levator palpebrae superioris does whta
elevates and retracts upper eye lid
superior rectus deos what
controls upward eye gaze
medial rectus...
controls medial eye movement
inferior rectus
controls downward eye gaze
inferior oblique
controls upward and medial eye gaze
the CNIII also supplies
the visceral motor component of 2 muscles
what are the two muscles supplied by CNIII
1. pupillary sphincter
2. ciliary muscles
pupillary sphincter does what
muscle that controls the size of the pupil
ciliary muscles does what
change the shape of the lens (accommodation) to focus on objects close. lens buldges out
what is the name of the nucleus projecting to these muscles
Edinger- Westphal nucleus
pupillary light reflex does what
constriction of pupil to light
accommodation reflex does what
reflex changes that enable an object to be focused on the retina
Oculomotor nerve lesions:

Central lesion:
both nuclei damaged (bilateral signs)
what happens with a lateral strabismus
eye deviates laterally
what is diplopia
double vision (when both eyes don't focus together) (one eye goes one way and one goes the other)
inability to move the affected eye...
medially or vertically
what is ptosis
drooping of the eyelid
what is abnormal pupillary light reflex
absence of pupillary constriction in the affected eye
inability for the affected eye to focus on..
near objects
what is CN IV
Trochlear nerve
what does CN IV supply
the superior oblique muscles
what are the superior oblique muscles concerned with
the downward and lateral movement of the eye
what would a person that could not do this have difficulties with
reading and walking down stairs
cell bodies are located in the...
contralateral trochlear nucleus
CN IV is the only CN that is (2)
1. attached to the dorsal surface of the brainstem
2. completely crossed (originating from a contralateral nucleus)
the CN IV decussates in the _____ prior to leaving the _______
damage to the trochlear nerve results in
insignificant deficit. ( not as bad...just one muscles. but still do have difficulties)
damage results in...
diplopia, when attempting to move eyes downarad and laterally (double vision)
lesion of the CN IV- ipsilateral or contralateral sign?
contralateral sign
what is the name of CN VI
abducens nerve
what abducens nerve supplies
the lateral rectus muscle
what does the CN VI do to the eye
abducts (moves eyes laterally)
fibers originate from the ....under....
ipsilateral abducens nucleus

under facial colliculus
where is CN VI located
in the caudal pons, beneath the floor of the 4th ventricle
facial nerve(motor fibers) wrap around the...
damage to the CN VI causes
medial strabismus- the affected eye deviates medially
what is the name of CN XII
hypoglossal nerve
what does CN XII do
innervates muscles of the tongue
where are cell bodies found
in the ipsilateral hypoglossal nucleus
the caudal to rostral medulla
located close to
midline (motor) beneath the floor of the 4th ventricle
lower motor lesion of CNXII results in ipsi or contra signs
what the three results of lesion..
1. weakness of oneside of the tongue- protrusion of the tongue results in deviation to the affected side
2. fasciculation (twitching of tongue)(rippling)(worm like)
3. atrophy of the affected side
bilateral lesions may cause difficulties in
speaking and eating
what are the somatic motor nerves
CNIII- oculomotor nerve
CNIV- trochlear nerve
CNVI- abducens nerve
CNXII- hypoglossal nerve
Branchiomeric Nerves: sensory or motor nerves?
motor nerves
what is the name of CN V
trigeminal nerve
CN V contains what kind of fibers?
motor and sensory fibers (mostly sensory)
primary function of CN V
transmission of the following information from the head (face):
1. tactile
2. proprioceptive
3. pain
4. temperature
3 divisions of primary afferent fibers
1. ophthalmic (V1)
2. Maxillary (V2)
3. Mandibular( V3)
all sensory information goes to...
post central gyrus
what are three sensory nuclei associated with trigeminal afferent fibers
1. main sensory nucleus
2. spinal nucleus
3. mesencephalic nucleus
what is the main sensory nucleus concerned with
discriminative tactile and proprioceptive sensations
the main sensory nucleus of the trigeminal nerve gives rise to imp. ascending pathway:
the dorsal trigeminal tract
describe the dorsal trigeminal tract: ipsi? contra? terminates?
uncrossed fibers (completely ipsilateral)

terminate in the ventral posteromedial (VPM) nucleus of the thalamus
afferent fibers reach the spinal trigeminal nucleus via the
spinal trigeminal tract
the spinal trigeminal nucleus is imp. in processing...
pain and temp info in the head
gives rise to ...(name and describe pathway)

joins the...
terminates in the...
ventral trigeminal tract-> a crossed ascending pain pathway-> joins the spinothalamic tract-> terminates in the VPM nucleus of the thalamus
the mesencephalic nucleus of trigeminal nerve carries... from... some from..
1. carry proprioceptive information
2. from the muscles of mastication(chewing)
3. some from the mechanoreceptors of gums, teeth, and hard palate
Trigeminal Nerve (CN V): trigeminal motor nucleus

the muscles of mastication (to move jaw up and down)

tensor tympani and other small muscles
where is the trigeminal motor nucleus located
in the midpons
trigeminal neuralgia is also called
tic douloureax
what is trigeminal neuralgia characterized by
brief attacks of excruciating pain in the distribution of the one or more divisions of the trigeminal nerve
frequently there is a ____ zone
trigger zone
what is a trigger zone
wehre tactile stimulation may precipitate an attack
what is the name of CN VII
facial nerve
somatic afferents from..
the skin of the outer ear
describe the tract of the somatic afferents of the facial nerve (CN VII)
the fibers enter the spinal trigeminal tract -> go to the VPM in the thalamus-> postcentral gyrus
visceral afferents carry info from
the nasal cavity and soft palate
describe the tract of visceral afferents
enter solitary tract and terminate in the solitary nucleus
what is the solitary nucleus
principal visceral afferent nucleus of the brain stem
what doe the special visceral afferents subserve (carry)
taste and olfaction(smell)
CN VII subserves taste on what part of the tongue and palate
anterior 2/3
describe the tract of the special visceral afferents
travels in solitary tract ot the solitary nucleus
the second- order taste fibers participate in
reflex activities (swallowing or coughing)
what is the tract of the second-order taste fibers
travel to the VPM -> gustatory cortex
what is at the gustatory cortex
sensation of smell
CN VII: Brancial motor innervates...
muscles of facial expression (smile) move cheeks, lips
branchial motor arises in
facial motor nucleus
facial motor nucleus invovled in
corneal blink reflex (with foreign objects touching cornea of eye)
sensory afferent of corneal blink reflex via..
trigeminal nerve
with CN VII

upper motor neurons innervate wht part of face bilaterlly
upper 1/3
upper motor neurosn innervate what part of face contralaterlly
lower 2/3
the lower motor neurons project to which muscles
unilateral upper motor neuron lesion results in
lower contralateral facial weakness
unilateral lower motor neuron lesion results in
weakness in the ipsilateral half of the face
bilateral lesions results in
entire face weakness

visceral efferents innervate (3)
1. submandibular gland
2. sublingual gland
3. lacrimal gland
what is the submandibular gland
salivation. glands under tongue, back of mouth
sublingual gland
lacrimal gland
tear secretion
the posterior column/medial lemniscus carries what kind of information
tactile and proprioception from body
the spinothalamic tract carries what kind of information
pain and temerpature from body
the spinal trigeminal/ventral trigeminal tracts carry what kind of information
pain and temp in head
the dorsal trigeminal tract carries what kind of information
tactile and proprioception in head
the solitary tract carries what kind of information
visceral sensory/ taste from head
droopy eyelids
facial weakness
inability to elevate the shoulder
weakness of tongue
loss of taste on the anterior tongue
trigeminal neuralgia (tic douloureax)
deviation of the uvula in production of /a/
loss of corneal blink reflex
lateral strabismus
medial strabismus
loss of sensation to the face
vocal fold paralysis and hoarseness
difficulty chewing
pain in the pharynx and external auditory meatus
double vision
loss of taste in the posterior tongue
her face felt tingly ___
she felt like gagging ____
she had a bitter taste in her mouth
she looked at the alarm clock which was within her arm's reach and focused on the hands of the clock ___
she picked up the newspaper and read it _____ but she felt the headache again
she gazed up at the picture on the wall___
she started to chew ___ a piece of gum
while taking a shower, she lost her footing and in her alarm she swallowed the gum _____
trying to put on some mascar,s he almost poked herself in the eye, which made her blink
her clumsiness agitated her so that she stuck out her tongue ____ and made a face at herself___ in the mirror
and then amanda suddenly yelled with a shrill voice___
she shrugged her shoulders ___
dorsal trigeminal tract carries what kind of info
tactile and proprioception info in the head
spinal trigeminal tract carries what kind of info
pain and temp info in head
what does the trigeminal motor nucleus innervate
-muscles of masticulation(jaw movement)
-tensor tympani
-other small muscles
the breif attack of excruciating pain in the distribution of the trigeminal nerve is
trigeminal neuralgia
CNVII subserves..
taste and olfaction on anterior 2/3 of tongue and palate
branchial motor fibers of CNVII innervate
muscles of facial expression
branchial motor fibers of CNIX innervate
stylopharyngeus muscle (elevation of pharynx during speech and swallowing)
2 effects of the lesion of CNIX
-loss of gag reflex
-loss of taste on posterior 1/3 of tongue
the attacks of severe pain in the distribution of CNIX is
glossopharyngeal neuralgia
3 speech functions of the branchial motor fibers of CNX
-velum movement
-pitch change
-vocal fold movment
3 potential effects of unilateral lesion involving CNX
-deviation of soft palate to the intact side
function of the cranial portion of CNXI
distributed to the branches of CNX-> innervates muscles of larynx and velum with the CNX
glossopharyngeal nerve
what are the four components of the glossopharyngeal nerve
1. branchial motor
2. visceral sensory
3. special visceral afferent
4. somatic afferent
branchial motor portion of CNIX arises from? innervates?
-arises from the nucleus ambiguus
-innervate stylopharyngeus muscle (elevation of pharynx during speech and swallowing)
Visceral sensory portion of CNIX carries what kind of info from? enters and terminates wehre?
-carry pain and temperature info from teh posterior tongue, pharynx, and eustachain tube

-enter the solitary tract and terminate in teh solitary nucleus
the Special visceral afferent portion of CN IX
-what part?
-subserves tasate and olfaction
-taste from the posterior 1/3 of the tongue and the pharyx
- course: solitary tract-> VPM-> postcentral gyrus(gustatory cortex)
somatic afferent portion of CNIX supplies
the skin of the outer ear
glossopharyngeal nerve lesion can cause (3)
- loss of gag refex
- loss of laste on the posterior 1/3 of tongue
- glossopharyngeal neuralgia
what is glossopharyngeal neuralgia? radiates where? how treated?
- attacks of pain in the posteior tongue of the walls of pharynx
- pain radiates to the vicinity of the ear
- pharmacological treatment or nerve resection
vagus nerve
which nerves travel very close to eachother so that a lesion in one means there is a lesion in the other
glossopharyngeal nerve and vagus nerve
the cnX is most representative of what
what are the four components of vagus nerve
1. visceral afferent
2. special visceral afferent
3. visceral efferent
4. branchial motor
visceral afferent portion of CNX vagus nerve:
-carry info from...
-fibers enter where and terminate where
-carry info from the larynx, esophagus, pharynx, thoracic and abdominal viscera

-in gerneral, fibers enter the solitary tract and terminate in the solitary nucleus
the special visceral afferent portion of CNX
- arise from
- identical course to
-arise from the taste buds of the epiglottis
- identical course ot CN VII and IX
Visceral efferent fibers of CNX travel to the
thoracic and abdominal viscera (e.g. heart)
Branchial motor fibers of CNX
-control what three factors of speech
-innervate striated (voluntary) muscles of the larynx, pharynx, and soft palate (imp. for speech and swallowing)

control- velum movement, pitch change, and vocal fold movement
Bilateral lesion to CNX results in (2)
- respriatory, cardiovascular and swallowing problems- can be fatal

-complete laryngeal paralysis
unilateral lesion to CNX -ipsilateral lesion (3)
-deviation of soft palate to the intact side
- hoarseness
- dysphagia
spinal accessory nerve
what are the two components of CN XI
1. cranial portion
2. spinal portion
cranial portion
-arises from
- distributed to/ innervates...
-arises from the nucleus ambiguus
- distributed to the branches of CN X-> innervates muscles of larynx and velum with the CNX (functions cannot be distiguished easily)
spinal portion
- originates from...
-originates from teh cervical spinal area
- innervates the sternocleidomastoid and part of ht trapezius
lesion of the spinal accessory nerve (CNXI) :ispilateral representation (3)
- weakness/difficulty in rotating head away from the side of the lesion
- weakness in elevation of shoulders on the affected side
- hoarse vocal quality
auditory and vestibular nerve
Inner Ear Structures:
what is the membranous labyrinth suspended within
the bony labyrinth
what is the vestibule
a large central area
what are the two structures attached to the vestibule
cochlea and semicircular canals
what is connect with the cochlea
saccule (hearing)
what is connected with semicircular canals
attached to the utricle (balance)
the bony labyrinth is filled with
the membranous labyrinth is filled with
the membranous labyrinth containing endolymph contains the
scala media
auditory hair cells (mechanoreceptors) (auditory receptors) are in the
organ of corti
the organ of corti is withiin the
scala media
the organ of corti is resting on the
basilar membrane
the organ of corti is made up of what
inner and outer hair cells
deformation of the hair cells leads to
depolarization of the hair cells
depolarization of the hair cells leads to
receptor potential generated
receptor potential generated leads to
transmission of the signal back along the auditory nerve to the brainstem (the cochlear division of the 8th nerve)
what is tonotopic organization within the auditory system
particular frequencies are mapped in an orderly fashion on to particular areas
in the organ of corti, hair cells at the apex respond best to? at the base?
at the apex respond best to low frequencies and at the base resond best to high frequencies
this organization is maintained thru to the entire
auditory system
central auditory pathways: receptors in the hair cells goes to...which then goes to
auditory primary afferentes (8th nerve) in the inner ear...which then enters the brainstem (CNS)
each fiber fiburcates and sends one branch to...
dorsal or ventral cochlear nucleus
cells from the ventral cochlear nucles project to the
superior olivary nuclesu (of both sides)
crossing some fibers...then goes to
lateral lemniscus
which then goes to
inferior colliculus (ipsilaterally) (midbrain)
superior olive is responsible for
the localization of sound source
fibers from the dorsal cochlear what..then what..
some fibers cross over and join the lateral lemniscus...then goes to inferior colliculus
the dorsal cochlear nucleus carries what
frequency and intensity information
both of the central auditory pathways are
does unilateral lesion along hte pathway cause deafness
no because bilateral inneravation
fromt he inferior colliculus goes to...and then goes to...
medial geniculate nucleus in the thalamus...then to superior temporal gyrus (heschl's gyrus) primary auditory gyrus
unilateral lesion that destroys the receptors, cochlear nerve (8th nerve) or the cochlear nucli will haveq
ipsilateral hearing loss
what may be restricted depending on the portiono f the cochlea that was damaged
certain frequencies
unilateral lesion higher up in the auditory pathway-> with have
no substantial hearing loss, due to bilateral innervation
may have difficulty
localizing sound
problem in the middle ear is what kind of hearing loss
the vestibular system contains
3 semicircular canals
what are the 3 semicircular canals called
horizontal, anterior, posterior
the vestibular system deals with
head movement in a space
a dialation at one end of each duct is a
the ampula contains
crista, covered by sensory hair cells
hair cells are embedded in
a gelatinous mass, called cupula
movement of the head leads to
the endolymph lags behind due to inertia
...which leads to
deflection of the cupula
....which leads to
stimulation of the hair cells
which leads to
receptor the CNVIII
the semicirular canals detect what kind of movement
the utricle and saccule detect what kind of movement
linear (elevator, in a car)
hair cells in the utricle and saccule are called
head movement leads to..
otolithic membrane flops around
..leads to
stimulates the hair celss
...leads to
signal the new position of the head
both utricle and saccule are sensitive to the _____ and ______
linear acceleration and head tilting
central projections:

hair cells...leads to
vestibular primary afferents
.leads to
enter the brainstem
break off from auditory fibers
end in the vestibular nuclear complex (at the level of rostral medulla/caudal pons)
some fibers go where directly
the vestibular nuclei have connections with what 4
1. cerebellum
2. the spinal cord
3. the motor nuclei of the CN III, IV, VI
4. the reticular formation
ascending tract:
medial longitudinal fasciculus (MLF)
MLF travels to the
extraocular motor nerves (III<IV< VI)
the MLF is concerned with
the conjugate movement of the eyes, coordinated with movement of the head, to maintain visual fixation
damage to the vestibular system can result in..4
loss of equilibrium, dizziness, nystagmus (jerky eye movment), visceral disturbances (stomach upset)