3/24 neuro Flashcards
corticospinal, spinothalamic tracts
-organization
-Legs (Lumbosacral) are Lateral in Lateral corticospinal, spinothalamic tracts.
DC/ML
-organization
-Dorsal column is organized as you are, with hands at sides. Arms outside, legs inside.
lateral corticospnial vs lateral spinothalamic
-so both are lateral, but which one is more ventral?
lateral spinothalamic = more ventral.
Which tract exclusively conveys vibration sense?
DC/ML
Remember, ascending tracts synapse and then cross.
remember that
gracile fasciculus = upper or lower limb?
Lower limb
cuneate fasciculus = upper or lower limb?
Upper limb
DC/ML
-where does it decussate?
medulla
Lissauer’s fasciculus
what the spinothalamic tract uses to ascend 1-2 levels before synapsing in dorsal horn.
UMN lesions
-where can the lesion be?
-any lesion in neurons from motor cortex up until
they synapse at anterior horn.
Atrophy
-UMN or LMN lesion or both?
- atrophy in LMN lesion.
- you get hypertonia w/UMN lesion.
Poliomyelitis & Werdnig Hoffman
-whats the lesion?
destruction of anterior horns.
- strictly a LMN lesion.
- flaccid paralysis.
ALS
-whats the only motor system that can not be affected?
oculomotor
ALS
-familial cases due to defect in what protein?
superoxide dismutase 1.
ALS
- aka?
- Tx? & how does Tx work?
- mnemonic?
- Lou Gehrig’s disease
- Riluzole treatment modestly inc. survival by dec. presynaptic glutamate release.
-for LOU gehrigs gives ri”LOU”zole.
Complete occlusion of anterior spinal artery
- what part of s. cord gets infarcted?
- whats spared?
- anterior 2/3rd
- dorsal columns & lissauers tracts
Complete occlusion of anterior spinal artery
- which part of s.cord hit the hardest?
- why?
-Upper thoracic ASA territory is a watershed area, as artery of Adamkiewicz supplies ASA below ~T8.
Complete occlusion of anterior spinal artery
-presentation?
-Complete loss of strength below the level of the injury w/loss of pain & temp sensation but preserved vibratory sense (DC spared).
Tabes dorsalis
-whats the lesion?
-demyelination of DC/ML.
-
Romberg test
-what does it test?
proprioception
-DC/ML test.
Tabes dorsalis
- DTRs?
- Romberg test?
- absence of DTRs
- (+) romberg test (aka you have a problem w/proprioception).
Besides B12, what other vitamin def. can cause subacute combined degeneration?
vitamin E.
subacute combined degeneration
-which tracts are affected?
- DC/ML
- lateral corticospinal tract
- spinocerebellar tract
Poliomyelitis
- where does it replicate before entering the blood stream?
- where can you recover the virus?
- oropharynx & small intestine.
- stool or throat.
Spinal muscular atrophy
- aka?
- lesion?
- inheritance?
- Werdnig-Hoffmann disease
- Congenital degeneration of anterior horns of spinal cord = LMN lesion.
- auto recessive.
Friedreich ataxia
- inheritance pattern?
- repeat?
- which chrom?
- which gene product?
- auto recessive
- GAA
- chrom. 9
- frataxin
Friedreich ataxia
-whats the problem?
-No frataxin (iron binding protein) => impairment in mitochondrial functioning => degen. of multiple s.cord tracts.
Friedreich ataxia
- Sxs?
- presentation?
- Muscle weakness and loss of DTRs, vibratory sense, and proprioception.
- Presents in childhood with kyphoscoliosis.
Friedreich ataxia
-DTRs?
-loss of DTRs.
Friedreich ataxia
-cause of death?
hypertrophic cardiomyopathy
-you can get iron deposition in heart.
Brown-Séquard syndrome
- what is it?
- whats the only tract that will be contralateral problems?
- hemisection of s.cord.
- spinothalamic bc it synapses so low.
which organ is the master controller of the autonomic nervous system?
hypothalamus
-sends neurons that activate sym/pres and para/pres.
T4
-dermatome?
nipple
-“teat pore”
T10
-dermatome?
umbilicus
- belly but-ten.
- important for early appendicitis pain referall.
L1
-dermatome?
inguindal ligament
-L1 = IL
Kneecaps
-dermatome?
L4
Down on ALL 4’s (L4).
Erection and sensation of penile and anal zones.
- aka the good stuff.
- dermatome?
S2, S3, S4
-“S2, 3, 4 keep the penis off the floor.”
About what level is the diaphragm?
nipple line
-T4
Achilles reflex
S1, 2—“buckle my shoe”
Patellar reflex
L3, 4—“kick the door”
Biceps reflex
C5, 6—“pick up sticks”
Triceps reflex
C7, 8—“lay them straight”
Cremaster reflex
L1, L2—“testicles move”
Anal wink reflex
S3, S4—“winks galore”
Primitive reflexes
- disappear by what age?
- inhibited by what part of the brain?
- why would they re-emerge?
- 1 year old
- frontal lobe
- frontal lobe lesion
Galant reflex
Stroking along one side of the spine while newborn is in ventral suspension (face down) causes lateral flexion of lower body toward stimulated side.
Which CNs lie medially at brainstem
- what do they have in common?
- mnemonic?
Purely motor CNs leave medially from brainstem.
-CN 3, 6, 12
- 3*2 = 6
- 6*2 = 12
Which is the only CN that arises from dorsal aspect of brainstem?
trochlear
-also the only one that decussates before innervating target (sup. oblique).
sup/inf colliculi
- which one is visual/auditory?
- mnemonic?
Your eyes are above your ears, and the superior
colliculus (visual) is above the inferior colliculus (auditory).
Whats the only CN you cant get a schwannoma on?
CN2
Cranial nerves
-CNS or PNS?
PNS
-except CN2
Only CN w/o thalamic relay to cortex?
olfaction, CN1
What inn. muscles of mastication?
CN 5
what inn. lacrimation & salivation (submandibular & sublingual).
CN 7
what inn. eyelids closing (orbicularis oculi)
CN 7
CN 9
-whats the only muscle it innervates?
stylopharyngeus
-its “style” is one of a kind.
what inn. parotid gland?
CN 9
which nerve keeps uvula midline?
vagus n.
CN 12
-inn. all intrinsic tongue muscles except:
palatoglossus (CN 10)
Which intrinsic tongue muscle does CN 10 innervate?
palatoglossus
what portion of brainstem are cranial nerve nuclei located?
tegmentum portion of brain stem
Midbrain—nuclei of which CNs?
CN III, IV
Pons—nuclei of which CNs?
CN V, VI, VII, VIII
Medulla—nuclei of which CNs?
CN IX, X, XII
Spinal cord—nucleus of which CNs?
CN XI
Corneal reflex
- afferent =
- efferent =
- afferent = V1 (ophthalmic)
- efferent = CN 7
Lacrimation
- afferent =
- efferent =
- afferent = V1 (ophthalmic)
- loss of reflex does not preclude emotional tears.
- efferent = CN 7
Jaw Jerk
- afferent =
- efferent =
- afferent = V3 (sensory—muscle spindle from masseter)
- efferent = V3 (motor—masseter)
Pupillary reflex
- afferent =
- efferent =
- afferent = CN 2
- efferent = CN 3
Gag reflex
- afferent =
- efferent =
- afferent = CN 9
- efferent = CN 10
viral meningitis
-CSF: glucose, protein levels
- normal glucose
- high protein
Clasp knife spasticity
-UMN or LMN lesion?
UMN lesion
Damage to external globus pallidus
-Sxs:
dec. movement
Damage to internal globus pallidus
-Sxs:
inc. movement
Basal nucleus of meynert
-what type of neurons
Houses the cell bodies of cholinergic neurons.
-ACh
Who should obtain the informed consent?
The person performing the procedure!
Which type of headache has pain behind the eye?
cluster headache
Which type of headache has flushing, sweating, lacrimation, pupillary changes?
cluster headache
Which type of headache is unilateral?
migraine
Cluster headache
- more common in men or women?
- when do they usually occur?
- Tx:
- 7x more common in men.
- at night, few hours after going to bed.
- oxygen, sumatriptan
Why is halothane rarely used in adults?
severely hepatotoxic
-can cause massive hepatic necrosis.
Alzheimers
-whats the chemical imbalance?
dec ACh
memantine
- what is it?
- what disease is it used for?
NMDA receptor antagonist
-used in alzheimers
uncus =
uncal herniation =
- uncus = medial temporal lobe
- uncal herniation = medial temporal lobe herniating through the tentorium cerebelli
First sign of uncal herniation?
ipsilateral fixed and dilated pupil.
What Sx is pathognomic for PCP intox?
vertical & horizontal nystagmus
paraneoplastic subacute cerebellar degeneration:
- which cells targeted?
- after which cancers?
-purkinje cells (output cells of cerebellum) small cell carcinoma of lung breast ovarian uterine
Trigeminal nerve
- which cranial foramina do each exit?
- mnemonic?
Divisions of CN V exit owing to Standing Room Only.
- Ophthalmic (V1) = Superior orbital fissure
- Maxillary (V2) = foramen rotundum
- Mandibular (V3) = foramen ovale
Optic canal
-what goes thru?
-CN II, ophthalmic artery, central retinal vein.
Superior orbital fissure
-what goes thru?
- CN 3, 4, 5 (V1), 6
- ophthalmic vein
- sympathetic fibers
Foramen spinosum
-what goes thru?
- middle meningeal artery
* this is whats ruptured in epidural hematoma.
Internal auditory meatus
-what goes thru?
CN VII, VIII
Jugular foramen
-what goes thru?
-CN IX, X, XI, jugular vein.
Foramen magnum)
-what goes thru?
-spinal roots of CN XI, brain stem, vertebral arteries.
What drains into the cavernous sinus?
Blood from eye & superficial cortex.
What passes thru the cavernous sinus?
CN III, IV, V1, V2, and VI and postganglionic sympathetic fibers en route to the orbit all pass through the cavernous sinus.
*3, 4, 6 all control eye movement.
Cavernous sinus syndrome
(e.g., due to mass effect, fistula, thrombosis)—ophthalmoplegia and corneal and maxillary sensation with normal visual acuity. CN VI commonly affected.
CN V motor lesion
-does jaw deivate toward or away from lesion?
- Toward lesion
- Jaw deviates toward side of lesion due to unopposed force from the opposite pterygoid muscle.
CN X lesion
-does uvula point toward or away from lesion?
-away from lesion
Uvula deviates away from side of lesion. Weak side collapses and uvula points away.
CN XI lesion
- shoulder drop on which side?
- troubling turning head to which side?
- Shoulder drop on side of lesion (ipsi).
- Weakness turning head to contralateral side of lesion.
CN XII lesion (LMN)
- which way does tongue point?
- mnemonic?
- Tongue deviates toward side of lesion.
- “lick your wounds”
Middle ear
-air or fluid filled?
-air filled
Auditory nerve signaling goes to what brain structure?
brainstem
Hearing thru bone conduction is abnormal, where must the disease process be?
-external, middle, or inner ear?
inner ear
Pts w/sensorineural hearing loss
- normal or abnormal rinne test?
- where will weber test localize?
- normal
- weber localizes to unaffected ear.
Pts w/conductive hearing loss?
- normal or abnormal rinne test?
- where will weber test localize?
- abnormal rinne test (bone>air).
- weber localizes to the AFFECTED ear.
*affected ear won’t be hearing background noise from outside (bc you have conductive hearing loss) so the bone sound will sound louder there.
Facial UMN lesion
- ipsi or contra?
- is any part spared?
- contralateral paralysis
- forehead spared due to bilateral UMN inn.
Facial LMN lesion
- ipsi or contra?
- is any part spared?
- ipsi paralysis
- nope, nothing spared.
Facial nerve palsy
- wheres the lesion?
- are Sxs ipsi or contra?
- facial nucleus or facial nerve (so its a LMN lesion).
- ipsilateral.
*inability to close eye on affected side.
Bell’s Palsy
-associated w/
- Lyme disease
- herpes simplex
- herpes zoster
- sarcoidosis
- tumors
- diabetes.
Corticobulbar tract
-a 2 neuron pathway connecting the cerebral cortex to the brainstem.
-primarily involved in carrying the motor function of the
non-oculomotor cranial nerves, like CN 7 for example.
-its one of the pyramidal tracts,in addition to corticospinal
tract.
Which muscles close jaw?
-mnemonic?
3 muscles close jaw: Masseter, teMporalis, Medial pterygoid.
-M’s Munch.
Which muscles open jaw?
-mnemonic
- lateral pterygoid.
- Lateral Lowers
Which nerve innervates all muscles of mastication?
V3
neurofibromatosis
-derived from what?
neural crest cells
Whats the most frequent CNS tumor in an immunosuppressed pt?
Primary CNS lymphoma
Why are prostaglandins used in glaucoma?
they inc. outflow of aqeuous humor
-ie. latanoprost
Latanoprost
- use?
- s/e:
- inc. aqueous drainage in glaucoma.
- darkens color of iris (browning)
neurofibromas are tumors of what cells which are derived from what tissue?
schwann cells (derived from neural crest)
Area postrema
- aka?
- location?
- is there BBB?
- chemoreceptor trigger zone (CTZ)
- dorsal medulla
- no BBB - it has fenestrated caps.
Myelination: will it increase or decrease:
-length constant:
- increase
* length constant = how far can an impulse travel w/o being dissipated, so of course myelin will lengthen that.
Myelination: will it inc or dec:
-time constant:
- decrease
- time constant = how fast a membrane can be depolarized. Myelin decreases membrane capacitance which reduces the time constant.
Myelination: will it inc. or dec:
-membrane capacitance:
decrease
Myelination: will it inc or dec:
-membrane resistance:
increase
Length constant
-what is it?
How far down an axon an electrical impulse can propogate.
-myelination increases it.
Blood in sulci & cisterns on CT
-what type of bleed?
subarachnoid hemorrhage
Where is the first area damaged in global cerebral ischemia?
hippocampus
-pyramidal cells
H1 vs H2
- which is gastric one?
- whats suffix?
H2
-“tidine”
chlorpheniramine
-what is it?
1st gen H1 blocker