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325 Cards in this Set
- Front
- Back
What is the origin of CN I?
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Olfactory mucosa of the upper portion of the nasal cavity
|
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What is the origin of CN II?
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Ganglion cells of the retina
|
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What is the origin of CN III?
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Oculomotor nucleus: midbrain at superior colliculus
Edinger-Westphal nucleus: anterior periaqueductal gray |
|
What is the origin of CN IV?
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Trochlear Nucleus: midbrain at inferior colliculus in the anterior periaqueductal gray
|
|
What is the origin of CN V?
|
Nucleus of spinal tract, chief sensory nucleus, mesencephalic nucleus, motor nucleus: midpons
|
|
What is the origin of CN VI?
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Lower pons at facial colliculus
|
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What is the origin of CN VII?
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Facial nucleus: lower pons
Nucleus of solitary tract, superior salivatory nucleus: medulla |
|
What is the origin of CN VIII?
|
Vestibular nuclei: lateral aspect of the 4th ventricle
Cochlear nuclei: acoustic tubercle |
|
What is the origin of CN IX?
|
Nucleus of solitary tract, nucleus ambiguus: medulla
Inferior salivatory nucleus: pons |
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What is the origin of CN X?
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Dorsal motor nucleus, nucleus ambiguus, nucleus of solitary tract, nucleus of spinal tract of the trigeminal: medulla
|
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What is the origin of CN XI?
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Nucleus ambiguus and disperse cell bodies: medulla and cervical segments
|
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What is the origin of CN XII?
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Hypoglossal nucleus: medulla
|
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The vestibularcochlear nuclei is found on the _______ of the ___ ventricle?
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Floor
4th |
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Where does the vestibularcochlear and facial nerve exit?
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Cerebellopontine angle
|
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What are the functions of CN VIII?
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Balance and equilibrium connected to the position and movement of the head and auditory
|
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A lesion to the vestibular portion results in what?
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Vertigo and nystagmus
|
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A lesion to the cochlear portion results in what?
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Deafness and tinnitus
|
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What is nystagmus?
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Uncontrollable rhythmical oscillations of the eye
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What is tinnitus?
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Persistent buzzing/ringing sound
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Is the facial nerve, CN VII, motor or sensory?
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Both motor and sensory
|
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What is the motor nucleus of the facial nerve and what does it control?
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Facial nucleus (pons)
Muscles of facial expression |
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What is the sensory nucleus of the facial nerve and what does it deal with specifically?
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Solitary nucleus (pons)
Taste of anterior tongue |
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What is the secretomotor nucleus of the facial nerve and what does it control?
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Salivatory nucleus (pons)
Salivary glands |
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What two nerves control the tongue?
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CN VII and IX
|
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What is an upper motor neuron lesion of the facial nerve and what does it effect?
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Supranuclear
Lower opposite side of the face |
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What is a LMN lesion of the facial nerve and what does it effect?
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Infranuclear
Same half of the face |
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What is a LMN lesion of the facial nerve also known as?
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Bell's palsy
|
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In the case of a facial nerve lesion, the effected area usually exhibits what?
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Inability to close eye, drooping lower eyelid, tearing, drooling, drooping of mouth, etc.
|
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What is a patient suspected of a facial nerve lesion asked to do?
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Smile while closing eyes tightly
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The trigeminal nerve is a _______ nerve (motor? sensory?)
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Motor AND sensory!
|
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What does the motor portion of the trigeminal nerve control?
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Muscles of mastication
|
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What trigeminal nucleus controls pain and temperature of the face and oral cavity?
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Nucleus of the Spinal Tract
|
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In the trigeminal nerve, what is in charge of proprioception?
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Mesencephalic nucleus (muscles of the face)
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In CN V, what controls pressure and discriminatory tactile sensation and of what structures?
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Principle sensory nucleus (skin of face, sinuses, nose, tongue, teeth and gums)
|
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What may occur if the trigeminal nerve has a lesion?
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Deviation of jaw, inability to bite down, tic douloureux, facial anesthesia, shingles, headache
|
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Shingles is the result of _________ causing _________ pain along the _________
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Herpes Zoster
Unilateral Pain Sensory distribution of the nerve |
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What is sudden unilateral severe sharp stabbing pain along the distribution of the nerve?
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Tic douloureux (trigeminal neuralgia)
|
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In a CN V lesion, what side does the jaw deviation occur on and why?
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Same side because of unopposed action of the contralateral side pterygoid muscle
|
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The Abducent nerve CN __, is a motor or sensory nerve?
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CN VI
Motor |
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Where it he nucleus and exit of CN VI?
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Nucleus is in the pons, exits between the basilar pons and pyramid of medulla
|
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What is the function of the Abducent? Ipsilateral or contralateral control?
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Innervate lateral rectus muscle of the eyeball
Ipsilateral |
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What is the failure to move the eyes laterally?
|
Medial stabismus
|
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What does the reticular formation control and a lesion of it may cause what?
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ANS, somatic and visceral sensation muscles
Coma |
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A lesion to the corticospinal tract of the pons results in what?
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Contralateral hemparesis of trunk and extremities
|
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A lesion to the corticobulbar tract or nucleus of the pons results in what?
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Contralateral weakness of the lower face
|
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A lesion tot he medial lemniscus of the pons results in what?
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Loss of vibration sensation, discriminatory tactile sensation and contralateral loss of proprioception
|
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The Bell-Magendie law states what?
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Sensory information enters spinal cord via dorsal roots
Motor information leaves via ventral roots |
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What is proprioception?
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Knowledge of limbs in space
|
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What cranial nerves are associated with the midbrain?
|
Oculomotor, CN III
Trochlear, CN IV |
|
What raises the superior eyelid?
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Levator palpebrae superioris
|
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What nerve innervates the superior oblique?
|
CN IV, Trochlear
(SO4) |
|
What nerve innervates the lateral recti muscle?
|
CN VI, Abducent
(LR6) |
|
Unless noted, what nerve innervates an eye muscle?
|
CN III, Oculomotor
|
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The oculomotor nerve has 2 nuclei at the level of _________ in the _________
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Superior colliculus
Periaqueductal gray |
|
What nuclei of the oculomotor innervates the ciliaris and sphincter papillae?
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Edinger-Westphal nucleus (parasympathetic)
|
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What occurs when light is shown on the eye pupil causing contraction?
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Pupillary light reflex
|
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What is the only nerve to exit dorsally?
|
CN IV, Trochlear
|
|
What is the focusing thickening adjustment of the ciliaris called?
|
Accomodation reflex
|
|
What is diplopia?
|
Double vision
|
|
Why does diplopia occur?
|
Loss of conjugate movement
|
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What is mydriasis?
|
Dilated pupil
|
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What causes mydriasis?
|
Paralysis of sphincter papillae and unopposed dilation action by sympathetic
|
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What is cycloplegia and what do you lose with it?
|
Paralysis of the ciliaris, loss of accommodation reflex
|
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The nucleus of the trochlear nerve lies in the _________ at the level of the _________
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Periaqueductal gray at the level of the inferior colliculus
|
|
What is lost when the oculomotor nerve is lesioned?
|
Ptosis, lateral strabismus, diplopia, mydriasis, cycloplegia, and loss of light reflex
|
|
What is lost when the trochlear nerve is lesioned?
|
Weakness of downward gaze and diplopia when looking downward and inward
|
|
Where does the trochlear nerve decussate?
|
Superior medullary velum
|
|
The nucleus of the abducent nerve is in the _________ beneath the _________
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Pons
Facial colliculus |
|
A lesion to the abducent nerve, CN VI, results in what 2 things?
|
Medial strabismus and diplopia
|
|
What occurs in the first week of neuroembryology?
|
Fertilization of egg by sperm, cleavage (series of mitotic division), implantation
|
|
What occurs in the second week of neuroembryology?
|
Reorganization of the blastocyst into a bilaminar embryonic germ disc
|
|
What three things occur during the third week of neuroembryology?
|
Gastrulation
Notochord and prechordal plate formation Neurulation |
|
During gastrulation, the _________ develops into the _________
|
Primitive groove
Epiblast |
|
The primitive groove becomes the _________ and moves down displacing the _________
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Primitive streak, primitive hypoblast
|
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Gastrulation results in the trilaminar disc, the components are what 3 things?
|
Endoderm
Ectoderm Hypoblast |
|
The remaining epiblast from gastrulation is what?
|
Ectoderm
|
|
The _________ condensing along the primitive streak forms what 2 things?
|
Mesoderm
Notochordal process and prechordal plate |
|
As the notochordal process becomes the notochord, they stimulate what tissue change?
|
Overlaying ectoderm into neural tissue
|
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The neural plate is derived from the _________?
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Ectoderm
|
|
The notochord is derived from what?
|
Mesoderm
|
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The notochord and the prechordal plate approximate to form what over the notochord?
|
Neural plate
|
|
What is neurulation?
|
Formation of the neural plate, neural tube and neural crest cells
|
|
The neural plate gives rise to what?
|
CNS
|
|
The neural crest cells give rise to what?
|
Parts of the CNS and other structures
|
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Persistence of mesenchyme formation, thus a lack of _________, results in _________
|
No primitive streak, sacroccogyeal teratoma
|
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The neural plate invaginates and closes forming what?
|
Neural tube
|
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The neural tube _________ of somites form the spinal cord; it has _________ walls and a _________ tube
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Caudal to the 4th pair
Thick wall Small tube |
|
What forms the brain?
|
Neural TUBE cranial to the 4th pair of somites
|
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What forms the ventricular system?
|
Neural CANAL cranial to the 4th pair of somites
|
|
During neurulation, where do the neural crest cells form and where do they end up?
|
Edge/hinge point
Under surface ectoderm |
|
What trunk structures are derived from the neural crest?
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DRG, sympathetic chain ganglion, parasympathetic chain ganglion, Schwann cells, melanocytes, adrenal medulla
|
|
Neural tube cells form _________ cells, which turn into the 3 stratified layers
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Neuroepithelial
|
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What are the 3 layers of the neural tube?
|
Ventricular (glial and neuroblasts)
Mantle (gray CNS from neuroblasts) Marginal (axons) |
|
Which neural tube plate produces the dorsal horn?
The ventral horn? What separates them? |
Dorsal: alar plate
Ventral: basale plate Sulcus limitans separates them |
|
During the 4th week, the DRG forms from the _________ eventually resulting in what key structure?
|
Neural crest cells
The spinal nerve |
|
For pathway formation, the medial branches from the DRG may do what 3 things?
|
Synapse with intermediolateral column and ventral horn cells
Ascend forming funiculi |
|
What is the failure of the neural folds to fully differentiate?
|
Craniorachischisis totalis
|
|
What are the 3 primary vesicles?
|
Proencephalon
Mesencephalon Rhombencephalon |
|
The forebrain becomes what secondary structures? What does each structure ultimately become?
|
Telecephalon (cerebrum)
Diencephalon (thalami) |
|
The midbrain becomes what secondary structures? What does each structure ultimately become?
|
Mesecephalon (midbrain)
|
|
The hindbrain becomes what secondary structures? What does each structure ultimately become?
|
Metencephalon (pons and cerebellum)
Myelencephalon (medulla and spinal cord) |
|
Failure to close what at 26 days may result in spina bifida?
|
Caudal neuropore
|
|
Failure to close what at 24 days may result in what?
|
Cranial neuropore, anencephaly
|
|
What is found in the mature ventricular system? What is it made of?
|
Choroid plexus of the ventricles
Pia mater |
|
Choroid plexus helps in the production of what?
|
CSF
|
|
_________ and _________ form the choroid plexus; together they are known as what?
|
Ependymal layer of neural tube and pia mater from neural crest cells
Tele choroidea |
|
What is hydrocephalus?
|
Blockage of CSF resulting in intracranial pressure and abnormal growth
|
|
What is obstructive hydrocephalus?
|
Narrow spaces with enlarged ventricles upstream of the blockage
|
|
What is aqueductal stenosis?
|
Tumor of midbrain or debris after hemorrhage compresses cerebral aqueduct
|
|
What marks the cranial end of the neural tube?
|
Lamina terminalis
|
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_________ is associated with the deep tendon reflex to prevent _________ injury
|
Muscle spindle
Muscle |
|
_________ is associated with the tension of muscle to prevent _________ injury
|
Golgi tendon organ
Tendon |
|
Where and what is the Golgi Tendon organ?
|
Encapsulated Ib proprioceptors in between the muscle and tendon
|
|
What synapses with the Ib interneuron?
|
Ib from Golgi
Cutaneous receptors Joint receptors |
|
What does the inhibitory Ib interneuron do?
|
Inhibits the alpha motor neuron pool of agonist
|
|
What is the flexion and crossed extension reflex?
|
A delta nociceptors cause the flexion (withdraw) of injured limb while extending contralateral limb
|
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The nucleus gracilis and cutaneous gives rise to _________, decussate to _________, end up as _________
|
Internal arcuate fibers
Medial lemniscus Ventral posterior lateral thalamic nucleus |
|
From the ventral posterior lateral thalamic nucleus the fibers run where?
|
Through the internal capsule to the somatosensory cortex (area 1 ,2, 3)
|
|
How is the deep sensibility tract examined?
|
Romberg's test
Dermatomes, tuning forks upper extremity position sense |
|
Where does proprioception come from?
|
Lower extremity (spinocerebellar tract)
Upper (cuneatus) |
|
What tracts are involved in pain and temperature regulation? What are they collectively known as?
|
Spinothalamic, spinoreticular, spinomesencephalic
Anterolateral system |
|
Describe the pathway of the spinothalamic tract all the way to the somatosensory cortex
|
Tract --> ventral white commissure --> ventral posterior lateral thalamic nucleus --> internal capsule --> 3, 1, 2
|
|
How is the pain and temperature tracts examined?
|
Pinwheel over dermatomes
|
|
What are the general structures of the basal ganglia?
|
Lentiform nucleus, caudate nucleus, subthalamic nuclues, substantia nigra
|
|
What individual structures are located in the lentiform nucleus?
|
Putamen, Globus Pallidus II, I
|
|
Where is the head of the caudate nucleus located?
|
Lateral wall of the anterior horn of the lateral ventricle
|
|
Where is the tail of the caudate nucleus located?
|
Roof of inferior horn of lateral ventricle ending inferiorly in the amygdala
|
|
What are the individual entities of the substantia nigra, and what does each secrete?
|
Pars compacta (dopamine)
Pars reticulata (GABA) |
|
What exactly is the corpus striatum?
|
Caudate nucleus and lentiform nucleus
|
|
What is comprised of the head of the caudate nucleus and the putamen?
|
Neostriatum
|
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In the basal ganglia cortex excite/inhibit pathways, the cortex secretes _________ from area ___
|
Glutamate, Area 4
|
|
What area of the cortex is excited/inhibited by the thalamus?
|
Area 6
|
|
What are the nuclei of the thalamus stimulated by globus pallidus I and II?
|
VA and VL thalamic nuclei
|
|
Excitation of area 6 and the supplementary cortex results in what?
|
Excitation of motor nucleus and initiation of movement
|
|
What are the hypokinetic disorders?
|
Akinesia (inability to initiate movements)
Bradykinesia (slowness and shuffling of movement) |
|
The largest group of hyperkinetic disorders are dyskinesias, name the subtypes of dyskinesia.
|
Chorea, ballismus, athetosis, dystonia
|
|
What may be the cause of Parkinson's disease?
|
Depletion of dopaminergic cells in the substantia nigra
|
|
What are possible treatments of Parkinson's?
|
L-Dopa, embryonic dopamine cells, pallidotomy (VA and VL nuclei cauterization)
|
|
What are the symptoms of Parkinson's?
|
Akinesia, bradykinesia, resting tremor, cogwheel rigidity, flexed posture, masking, shuffling
|
|
What is Huntington's disease?
|
Autosomal disease, onset at 40s-50s, slow degeneration of neurons in striatum
|
|
What are the symptoms of Huntington's disease?
|
Chorea, dementia, behavioral or psychiatric disturbances
|
|
How soon after onset do patients normally die from Huntington's disease?
|
15-20 years (also high suicide rate)
|
|
What is chorea?
|
Involuntary twitching of the extremities and face that progressively worsens and expands
|
|
What is Sydenhams chorea?
|
Transient childhood chorea associated with rheumatic fever and affects the striatum
|
|
What is athetosis?
|
Degeneration of globus pallidus, results in writhing movements of distal extremities
|
|
What is ballism?
|
Lesion of subthalamic nucleus, contralateral involvement, movements of proximal extremities and trunk
|
|
What is Wilson's disease?
|
Can't metabolize Cu, Cu accumulates in liver and becomes toxic to liver and basal ganglia
|
|
What are some symptoms of Wilson's disease?
|
Liver cirrhosis, Keyser-Fleischer ring (Cu ring around iris)
|
|
What is an injury of the lentiform nucleus resulting in c-contractions called?
|
Dystonia, musculorum deformans
|
|
What is torticollis?
|
Focal dystonia
Constant spasms of SCM and tracts |
|
What is an upper eyelid focal dystonia (twitch) called?
|
Blepharospasm
|
|
What can be seen in a brain horizontal in a patient with Wilson's disease?
|
No caudate, little putamen
|
|
What are the cortical associations areas?
|
Anterior frontal lobe, posterior parietal lobe
|
|
What do the cortical association areas and basal ganglia do?
|
Motor and sensory environmental respectance to self
|
|
What was the target of the thalamus in the direct/indirect pathways?
|
Area 6 (pre-motor and supplementary motor cortex)
|
|
What is the primary motor cortex?
|
Area 4 in the pre-central gyrus
|
|
What is the function of the cerebellum and motor cortex in motor control?
|
Plan the sequence and timing of muscle contraction and relaxation of muscle for smooth motion
|
|
What areas are located in the post-central gyrus?
|
3, 1, 2
|
|
What are the 2 descending pathways for the execution of movement?
|
Lateral pathway and ventromedial pathway
|
|
Where is the lateral pathway located and what tracts are included in it?
|
Lateral funiculus, lateral corticospinal tract and rubrospinal tract
|
|
The lateral pathway influences motor neurons that innervate _________
|
Distal muscles of limbs
|
|
The medial pathway influences motor neurons that innervate _________
|
Axial and proximal limb muscles
|
|
Why do we mainly see lower face systems?
|
The corticobulbar tract for LMNs of brainstem is bilateral
|
|
UMN lateral corticospinal tract goes from the motor cortex to the distal flexors. Map it.
|
Corona radiata --> posterior limb --> crus cerebri --> basilar pons --> pyramid --> posterior decussation
|
|
Rubrospinal tract begins with the _________ nucleus, crosses the pons and innervates the _________
|
Distal flexor muscles
|
|
What are the symptoms of lateral pathway injury?
|
Paresis/paralysis, spasticity, hyper reflexes, clasp knife rigidity, Babinski, no superficial reflex
|
|
What tracts tend to overtake most of the rubrospinal tract function?
|
Corticospinal
|
|
The pontine reticulospinal tract begins in the _________ and ends in the _________
|
Reticular formation in pons, bilateral ventral horns
|
|
What does the pontine reticulospinal tract innervate?
|
Antigravity muscles (example: quadriceps femoris, scalenes)
|
|
Where does the medullary reticulospinal tract begin and end?
|
Reticular formation of medulla --> bilateral ventral horns
|
|
What is the purpose of the medullary reticulospinal tract?
|
Inhibit antigravity muscles
|
|
Where does the vestibulospinal tract begin and end?
|
Vestibular nuclei --> bilateral ventral horns
|
|
What is the purpose of the vestibulospinal tract?
|
Head and back muscles on directional info from ear, also innervates upper and lower limb extensors
|
|
What is the path of the tectospinal tract?
|
Superior colliculus --> cross in medulla --> ventral horn
|
|
What is the purpose of the vestibulospinal tract?
|
Coordinates head and eye movements
|
|
What tracts would be lost with a lesion to the vestibular nuclei?
|
Corticospinal and rubrospinal
|
|
What is decerebrate rigidity? What also needs to be cut to reduce it? Stop it?
|
Tonic extension, vestibular nerves, dorsal roots
|
|
What is decorticate rigidity?
|
Tonic extension of legs with flexion of arms
|
|
What tract tends to cancel each other out therefore they cannot prevent the 2 rigidities?
|
Pontine and medullary reticulospinal tract
|
|
Why is there no tonic extension in the arms with decorticate rigidity?
|
Red nucleus projections can counteract the vestibular extension function of the arms
|
|
In the ventral horn, extensors tend to be _________ placed, and distal muscles _________ placed
|
Extensors, distal muscles
|
|
Extrafusal muscles (power generating) are innervated by _________ neurons
|
Alpha-motor neuron
|
|
What are intrafusal muscles and what are they innervated by?
|
Muscle fibers within muscle spindles, gamma motor neurons
|
|
What is a muscle fasciculation?
|
Visible muscle twitching from contraction of an entire motor unit (motor unit disease)
|
|
What is a muscle fibrillation?
|
Spontaneous activity of a single muscle fiber (muscle denervation/myopathy)
|
|
What is a muscle spindle comprised of?
|
Intrafusal muscle, sensory afferents and motor axons
|
|
What is the purpose of the gamma innervated intrafusal muscles?
|
Keep muscle spindle open for maintenance of sensitivity
|
|
The proprioceptors of the muscle spindle send info to the ___ and ___
|
FC, FG
|
|
What type of fibers in the muscle spindle detect muscle stretch?
|
Ia, II
|
|
What is a dynamic intrafusal fiber?
|
Sensitive to rate of change (fire during input), Ia
|
|
What is a static intrafusal fiber?
|
Slowly adapting stretch receptors (fire at start and end), Ia & II
|
|
The dynamic and static intrafusal fibers are subtypes of what group?
|
Nuclear bag fibers
|
|
Describe the stretch reflex?
|
Monosynaptic connection between Ia and alpha motor causing muscle contraction in response to stretch
|
|
The Ia inhibitory interneuron inhibits the _________
|
Antagonist muscle
|
|
What prevents the over-excitation of muscles around a joint?
|
Recurrent Renshaw cell inhibition
|
|
Specifically, what does the Renshaw inhibitory cell do?
|
Excites the antagonist and inhibits agonist
|
|
What structures are found in the limbic lobe?
|
Septal area, cingulate gyrus, parahippocampal gyrus, hippocampus, amygdala, uncus
|
|
In addition to the limbic lobe, what structures are found in the limbic system?
|
Hypo-, epi-, thalamus, brainstem reticular formation, olfactory cortex, pre-frontal cortex
|
|
What are the components of the hippocampal formation?
|
Parahippocampal gyrus, hippocampus, dentate gyrus, subculum
|
|
What is the function of the hippocampus?
|
Map of spatial memory, learning, passage of short term to long term explicit memory
|
|
What is the order of projection (efferent route) of the hippocampal formation?
|
Hippocampus --> fornix --> mammillary bodies --> anterior nucleus of the thalamus --> cingulate gyrus
|
|
Afferents enter the hippocampal formation from what sources?
|
Entorhinal area, thalamus, locus coeruleus, raphe nucleus, ventral tegmental area, hippocampal commissure
|
|
The afferents from the hippocampal commissure arrive from what place?
|
Contralateral hippocampus
|
|
The entorhinal area of the parahippocampal gyrus is part of what cortex?
|
Primary olfactory cortex
|
|
A lesion to the hippocampal formation would result in what?
|
Defects in explicit memory and spatial orientation
|
|
Where are the cell bodies of the hippocampus found?
|
Fornix
|
|
What are the subtypes of explicit memory? What is it also known as?
|
Episodic (events) and semantic (facts)
Declarative memory |
|
Where is explicit memory found (aside of hippocampal formation)?
|
Medial temporal lobe
|
|
What are the types of implicit memory?
|
Priming, procedural, emotional and musculoskeletal responses to associative learning
|
|
All sensory information hits the _________ before it goes to its proper cortex
|
Amygdala
|
|
Priming occurs in the _________, and procedural memory in the _________
|
Neocortex, striatum
|
|
Where do emotional responses to associative learning occur? Musculoskeletal responses?
|
Amygdala, cerebellum
|
|
Efferents from the amygdala travel via _________ to what 4 areas?
|
Stria terminalis, septal nuclei, hypothalamus, brainstem, cortex
|
|
What type of information converges upon the amygdala?
|
Autonomic, sensory, auditory, and visual information
|
|
What is the function of the amygdala?
|
Affective perception of sensory stimuli
|
|
Overstimulation of the limbic system may result in what?
|
Intense feeling of fear, possibly olfactory hallucination
|
|
What are the limbic system syndromes/diseases?
|
Kluver Bucy syndrome, Korsakoff's syndrome, temporal lobe epilepsy, Schizophrenia, Alzheimer's
|
|
What is the lesion of Kluver Bucy syndrome?
|
Bilateral complete lesion of amygdala and hippocampal formation
|
|
What are the results of Kluver Bucy syndrome?
|
Visual agnosia, hyperorality, hypersexuality, docility, apathy, bulima, memory deficit
|
|
The senile plaques containing an _________ are found in the _________ and _________ cortices of Alzheimer's
|
Amyloid protein, temporal frontal and parietal cortices
|
|
What are the symptoms of temporal lobe epilepsy?
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Olfactory/visual/auditory hallucinations, lip smack, motor acts, temporal amnesia, aggressiveness
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What is the function of the septal area?
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Emotional behavior, reward reaction, transient rage, water consumption
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Sound below 20Hz is known as _________, above 20kHz _________
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Infrasound
Ultrasound |
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What are the muscles of the inner ear? What are they innervated by?
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Tensor tympani and stapedius muscle
CN VII |
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The cochlea spirals around what?
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Bony modiolus
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The tensor tympani connects to the _________ and functions for what purpose?
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Malleus
Make ossicles more rigid to protect against loud sounds |
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Why do sudden loud sounds hurt?
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Tensor tympani and stapedius muscles attenuation reflex is at a 50 - 150msec delay
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How does the middle ear amplify the sound pressure 22 times?
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Large surface to small surface
Ossicles act as levers |
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Displaced by the stapes, the _________ causes _________; any unabsorbed energy distorts the _________
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Oval window
Fluid movement Round window |
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The membranes are located at the _________
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Body
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Where is the basilar membrane thicker?
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At the apex
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Extracellular space of detector cells contain what?
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K+
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The scalas vestibuli (SV) and scalas tympani (ST) contain _________, which is rich in _________
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Perilymph, Na+
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Name, in order, the spaces and structures of the cochlea
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SV, Reissner's membrane, scalas media, basilar membrane, ST
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The SM contains _________, which is rich in _________ due to _________ secreting K+ while _________
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Endolymph, K+, stria vascularis, absorbing Na+
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What are the sensory cells on the basilar membrane?
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Organ of Corti
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How is sound coded in the basilar membrane?
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Base/narrow/rigid = high frequency
Apex/wide/floppy= low frequency |
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The basilar membrane is wide at the _________ of the cochlea
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Apex
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The Organ of Corti contains _________, _________ cells and _________ cells
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Rods of corti
Inner and outer hair cells Supporting cells |
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Organ of Corti sits on the __________ and is covered by the __________
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Basilar membrane, tectorial membrane
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What produces the receptor potential?
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Bending of the 100 stereocilia of each hair cell
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Which hair cells have stereocilia extending into the tectorial membrane?
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Outer hair cells
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Inner hair cells synapse with the __________ whose axons form the __________
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Bipolar spiral ganglion cells
Cochlear nerve |
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Which hair cells are distal to the pillar cells?
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Outer hair cells
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What happens when stereocilia bend due to upward movement?
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K+ channels open, depolarize, Ca+ channels open, neurotransmitter (glutamate) release on spiral ganglion
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Downward movement of the basilar membrane causes __________
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Hyperpolarization
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How do we know that outer hair cells may deal with amplification?
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Ototoxic antibiotics destroy them leading to hearing loss
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How many spiral ganglion cells are there?
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30,000
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Spiral ganglion cells form the __________ and later synapse with the __________
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Cochlear nerve, cochlear nuclei
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Each fiber of the spiral ganglion holds a specific frequency, thus it has __________
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Tonotopic organization
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What type of cells are in the ventral cochlear nuclei and what do they do?
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Stellate (frequency encode), Bushy (fire at sound onset and aid in horizontal localization)
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What type of cells are in the dorsal cochlear nucleus and what do they do?
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Fusiform (frequency encode, aid in vert sound localization)
Tuberculoventral (delayed, inhibit echo) |
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If you lesion one side after the cochlear nuclei what would result?
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Bilateral hearing loss with more pronounced contralaterally
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how is horizontal localization achieved?
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Medial olivary nucleus processes auditory time delay between ears
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When is interaural time delay the most striking? Interaural intensity?
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Low frequencies, high frequencies
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In addition to round window distention, how are echos avoided?
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Hyperpolarization and resting phases
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Intensity difference between the two ears is detected by the __________
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Lateral superior olivary nucleus
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The cochlear nerve fibers synapse __________ with the __________, who's fibers form the __________
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Superior olivary nuclei
bilaterally Lateral lemniscus |
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Some fibers from the lateral lemniscus synapse with the __________; most synapse with the __________
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Nucleus of the lateral lemniscus, inferior colliculus
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Describe the inferior colliculus.
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4 layer dorsal nucleus (auditory and somatosensory) and multi-central nucleus with a complete tonotopic map
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The __________ holds a complete __________ and receives fibers from the inferior colliculus
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Medial geniculate nucleus
Somatotopic map |
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What is the primary auditory cortex?
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Transverse Temporal Gyri of Heschl (area 41, 42) near superior temporal gyrus
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Conductive hearing loss results from __________
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Insult to the middle ear
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Sensorineural hearing loss results from __________
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Loss of cochlear hair cells
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What does otosclerosis result in?
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Ossification of ossicle attachments
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Otis media results from __________
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Scar tissue on tympani ossicles
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The TTG of Heschl is __________ organized and is the second point of what?
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Tonotopically, localization of sound (columns responsive to frequency and interaural relationships)
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Where is the tuning fork placed in Weber's test?
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Vertex or nasion
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Sound lateralization in Weber's could mean what 2 things?
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Lateralizes to conductive deaf ear, lateralizes away from sensorineural ear
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Where is the tuning fork placed in Rinne's test?
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Mastoid process, later by ear when fork is more quiet
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After the fork is moved, and the patient cannot hear it __________ loss is suspected.
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Conductive
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For Rinne's, if time of hearing significantly differs between ears __________ loss is suspected
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Sensorineural
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What is the labyrinth composed of?
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Cochlea, vestibule, and semicircular canals
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The bony labyrinth contains __________ and is continuous with the __________
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Perilymph Na+
CSF |
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The membranous labyrinth communicates with the __________
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Endolymphatic sac
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What does the endolymphatic sac continually absorb?
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Endolymph
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The vestibular system helps with what 3 things?
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Posture, muscle tone, and eye position in respect to the head
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In the static labyrinth, the hair cells are called the __________ and __________
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Macula utricle, macula succuli
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What are the static hair cells embedded in and what does it change?
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Gelatinous otolithic membrane containing CaCO3
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The static labyrinth is comprised of __________ and detect __________
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Utricle and saccule
Static orientation in respect to gravity |
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The semicircular canals can detect all possible direction of movement, how?
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Orthogonally oriented
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The kinetic labyrinth, which detects __________, contains the __________
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Angular deceleration/acceleration
Semicircular cells |
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What are the labyrinth hair cells and where are they located?
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Crista ampullaris, ampullae
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The crista ampullaris is embedded in the __________
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Gelatinous cupula
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__________ influx causes vestibular hair cell depolarization
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Potassium
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Vestibular hair cells have __________ on one end, and __________ on the other end
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Microvilla
Kinocilium |
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When microvilla __________ the cell will depolarize
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Bend toward the kinocilium
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When does the cell hyperpolarize?
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When microvilla bend away from the kinocilium
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V. receptors synapse with __________ cells of the __________ whose axons form the __________
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Bipolar cells, vestibular ganglia, vestibular nerve
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Where does the vestibular nerve enter the brainstem?
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Cerebellopontine angle lateral to facial
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What 3 places does the vestibular nuclei project?
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Vestibulospinal tract, flocculonodular lobe and fastigial nerve of cerebellum, nerve of CN III, IV, VI via MLF
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Fibers from the vestibular nerve may also ascend to the __________ and from there to the __________
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Ventral posterior thalamic nucleus, parietal association area
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Why does internuclear opthalmoplegia occur in a MLF lesion?
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CN VI can no longer synchronize with CN III
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With what diseases is internuclear opthalmoplegia often seen?
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MS, vascular diseases (NOT vestibular disease specific)
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Describe the Barany chair test
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patient flexes forward while being spun, stopped abruptly
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What is the result of the Barany chair test in an intact system?
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Nystagmus opposite that of direction of rotation
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Describe caloric testing.
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Warm of cold water is placed in the external acoustic meatus
Nystagmus= COWS (cold opposite, warm same) |
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What are the symptoms of a vestibular lesion?
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Vertigo, nystagmus, disequilibrium
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How can you tell a central vestibular lesion from a peripheral vestibular lesion?
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Central: nystagmus in all directions without vertigo
Peripheral: nystagmus horizontal with vertigo |
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What is Meniere's disease?
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Equilibrium loss, nystagmus vertigo, progressive hearing loss and tinnitus, onset in 20s-30s
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An acoustic neuroma is __________ and usually found at __________
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Common benign Schwann cell tumor, internal acoustic meatus or cerebellopontine angle
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An acoustic neuroma may also effect what nerves?
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Facial and trigeminal nerves
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Most odors that we can smell are __________
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Noxious
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Where is the olfactory epithelium?
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Top of nasal cavity around cribiform plate
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What makes the olfactory nerve a unique sensory tissue?
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Old receptors can be replaced regularly with new ones
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Olfactory receptor cells are __________ whose __________ form the __________
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Bipolar cells, unmyelinated axons, olfactory nerve
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What helps to trap odorants?
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Mucous and odorant binding proteins
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The olfactory nerve travels and synapses with the __________ cells of the __________
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Mitral and tuft
Olfactory bulb |
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What ion movement depolarizes the olfactory cell?
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Ca2+ IN
Cl- OUT |
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Bulb fibers proceed into the __________ and divides into the __________
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Olfactory tract
Medial and lateral olfactory stria |
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What makes up the primary olfactory cortex?
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Piriform and entorhinal cortex in the anterior parahippocampal gyrus
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Olfaction is the only sense to __________
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Reach cortex WITHOUT synapsing in the thalamus
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The piriform cortex relays information to the __________ and __________
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Orbitofrontal olfactory cortex
Dorsomedial thalamic nucleus |
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What is the primary olfactory association cortex?
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Orbitofrontal olfactory cortex
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The facial nerve has what branch/nerve receiving information from the tongue?
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Chorda tympani
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What cranial nerves synapse in the __________ nucleus for taste?
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CN VII, IX, X
Solitary nucleus |
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Name the ganglion for each CN of taste.
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CN VII: genicular ganglion
CN IX: inferior ganglion CN X: inferior-nodose ganglion |
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Afferents of the solitary nucleus synapse with the __________ travel through the __________ to the __________
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Ventral posteromedial thalamic nucleus, posterior limb, primary gustatory cortex
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Where is the primary gustatory cortex located?
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Post-central gyrus, operculum, superior portion of insula
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Gustatory afferents are ________
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Pseudounipolar
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How is a salty taste sensation generated?
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Na in --> depolarization --> Ca in--> vesicular release
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How is a sour taste sensation generated?
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H in --> K cannot leave --> depolarization --> Ca in --> vesicular release
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How is a sweet taste sensation generated?
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G protein --> K cannot leave --> depolarization --> Ca in --> vesicular release
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How is a bitter taste sensation generated?
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K cannot leave --> depolarization --> vesicular release
or G protein --> internal Ca release --> vesicular release |
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How is an umami taste sensation generated?
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Na in --> depolarization --> Ca in --> vesicular release
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