Neuro Flashcards
(152 cards)
1
Q
The forebrain (prosencephalon) develops into what?
A
Telencephalon and diencephalon
2
Q
What are the wall and cavity derivatives of the telencephalon?
A
Walls: cerebral hemispheres, Cavities: lateral ventricles
3
Q
What secondary vesicles does the Hindbrain (rhombencephalon) develop into?
A
Metencephalon and myelencephalon
4
Q
What are the wall and cavity derivatives of the diencephalon?
A
Walls- thalamus, cavity- 3rd ventricle
5
Q
What are the wall and cavity derivatives of the mesencephalon?
A
walls- midbrain, cavity- aqueduct
6
Q
What are the wall and cavity derivatives of the metencephalon?
A
walls-> pons and cerebellum, cavity-> upper part of 4th ventricle
7
Q
What are the wall and cavity derivatives of the myelencephalon?
A
walls-> medulla, cavity -> lower part of 4th ventricle
8
Q
What are the characteristics of spina bifida occulta?
A
Failure of bony spinal canal to close, no structural herniation. Dura in tact
Usually seen at lower vertebral levels, associated with tuft of hair or skin dimple at level of defect
Normal AFP**
9
Q
What are the findings in anencephaly?
A
Malformation of anterior neural tube-> no forebrain, open calvarium
Findings: increased AFP, polyhydramnios
10
Q
What maternal conditions are associated with anencephaly?
A
Type 1 diabetes, low folate
11
Q
Holoprosencephaly can be found in which syndromes?
A
Patau syndrome and fetal alcohol syndrome
12
Q
What mutation can cause holoprosencephaly?
A
sonic hedgehog signaling pathway mutations
13
Q
Chiari II
A
herniation of cerebellar tonsils and vermis through foramen magnum w/ aqueductal stenosis and hydrocephalus
Usually presents with meningomyelocele, paralysis below defect
14
Q
Dandy-Walker
A
Agenesis of cerebellar vermis with cystic enlargement of 4th ventricle (fills enlarged posterior fossa)
Associated with spina bifida and hydrocephalus
15
Q
What is syringomyelia associated with?
A
Chiari malformations, trauma and tumors
16
Q
What causes syringomyelia? How does it present?
A
cystic cavity (syrinx) within spinal cord
Crossing anterior spinal commissural fibers damaged first -> “cape-like” bilateral loss of pain and temp in upper extremities (fine touch preserved)
Symptoms usually present in late adulthood
17
Q
Where in the spinal cord is syringomyelia most common?
A
C8-T1
18
Q
Anterior 2/3 of tongue -> what brachial arches is it derived from? CNs for taste and sensation?
A
Brachial arches 1 and 2
Taste - CN VII, Sensation - CN V3
19
Q
Posterior 1/3 of tongue -> what brachial arches is it derived from? CNs for taste and sensation?
A
Brachial arches 3 and 4
Taste and sensation - CN IX, extreme posterior CN X
20
Q
What muscle retracts and depresses the tongue and what CN innervates it?
A
hyoglossus, CN XII
21
Q
What muscle protrudes the tongue and what CN innervates it?
A
genioglossus, CN XII
22
Q
What muscle draws sides of tongue upward and what CN innervates it?
A
styloglossus, CN XII
23
Q
What muscle elevates posterior tongue during swallowing and what innervates it?
A
palatoglossus, CN X
24
Q
What can be seen on Nissle staining?
A
Stains RER -> can see dendrites and cell body, but NOT axons
25
What is Wallerian degeneration
injury to axon causes degeneration distal to injury and axonal retraction proximally
26
What is the function of astrocytes and what are they derived from?
Derived from neuroectoderm
Function: physical support, repair, K+ metabolism, remove excess NT, component of BBB, glycogen reserve buffer, reactive gliosis in response to neural injury
27
What is the marker for astrocytes?
GFAP
28
What does HIV-infected microglia cause
HIV infected microglia fuse to form multinucleated giant cells in CNS
29
What are microglia derived from? What is their function?
Derived from mesoderm, mononuclear origin
Function: phagocytes of CNS, activated in response to tissue damage
*Not readily discernible by Nissl
30
What is the myelin of CNS and PNS?
CNS- oligodendrocytes, PNS- Schwann cells
31
Acoustic neuroma - what is it and what can it be associated with?
Type of schwannoma, usually in internal acoustic meatus (CN VIII)
If bilateral, strong associate with neruofibromatosis type 2 (autosomal dominant)
32
How many axons do schwann cells myelinate?
each schwann cell myelinates 1 PNS axon
33
What are Schwann cells derived from?
Neural crest
34
How many axons do oligodendrocytes myelinate?
Many axons (~30)
35
What are oligodendrocytes derived from? How do they appear histologically?
Derived from neuroectoderm
"Fried egg" appearance on histology
36
Which diseases injure oligodendrocytes?
MS, PML, leukodystrophies
37
What type of fibers use free nerve endings? Where are free nerve ending receptors located and what do they sense?
Fibers: C- slow, unmyelinated and A delta - fast, myelinated
Location: all skin, epidermis, some viscera
Senses: pain and temperature
38
What type of fibers have Meissner corpuscles? Where are Meissner corpuscles located and what do they sense?
Fibers: large, myelinated; adapt quickly
Location: Glabrous (hairless) skin
Senses: dynamic fine/light touch, position sense
39
What type of fibers have Pacinian corpuscles? Where are Pacinian corpuscles located and what do they sense?
Fibers: large, myelinated; adapt quickly
Location: Deep skin layers, ligaments, joints
Senses: Vibration and pressure
40
Merkel discs are associated with what kinds of fibers? Where are Merkel discs located and what do they sense?
Fibers: large, myelinated; *adapt slowly
Location: finger tips, superficial skin
Senses: pressure, deep static touch (shapes, edges, etc), position sense
41
Ruffini corpuscles are associated with what kinds of fibers? Where are Ruffini corpuscles located and what do they sense?
Fibers: dendritic endings with capsule, adapt slowly
Location: finger tips, joints
Senses: (sensitive of skin stretch and kinesthetic sense) pressure, slippage of objects along surface of skin, joint angle change
42
What part of peripheral nerves invests single nerve fiber layers?
Endoneurium, connective tissue that invests myelin sheath of nerve fibers
43
What surrounds a fascicle of nerve fibers?
Perineurium, note: must be rejoined in microsurgery for limb reattachment
44
What is the epineurium?
Dense connective tissue that surrounds entire nerve, contains the nerve fascicles and blood vessels that supply nerve
45
Where is Norepinephrine synthesized?
Locus ceruleus (pons)
46
How does NE change in disease?
increases in anxiety and decreases in depression
47
Where is dopamine synthesized?
ventral tegmentum and substantia nigra pars compacta (midbrain)
48
How does dopamine change in disease?
increases in Huntington disease
| decreases in Parkinson disease, depression
49
Where is serotonin (5-HT) synthesized?
Raphe nuclei (pons, medulla, midbrain)
50
How does serotonin (5-HT) change in disease?
decreases in anxiety and depression
51
Where is ACh synthesized?
Basal nucleus of Meynert
52
How does ACh change in disease?
increases in Parkinson disease
| decreases in Alzheimer disease and Huntington disease
53
Where is GABA synthesized?
Nucleus accumbens
54
How does GABA change in disease?
decreases in anxiety and Huntington disease
55
What forms the BBB?
Tight jxns between nonfenestrated capillary endothelial cells, basement membrane, astrocyte foot processes
56
How do glucose and amino acids cross BBB?
slowly via carrier-mediated transport
57
What is the nucleus related to "stress and panic"
locus ceruleus
58
what are the nuclei associated with "reward center, pleasure, addiction and fear"?
nucleus accumbens and septal nucleus
59
how do nonpolar/lipid-soluble substances cross the BBB?
rapidly via diffusion
60
which areas of the brain have fenestrated capillaries and allow molecules in blood to affect brain function (circumventricular organs)?
Area postrema - vomiting after chemo
OVLT - osmotic sensing
neurohypophysis (posterior pituitary) - ADH release
61
Which nucleus makes ADH?
supraoptic nucleus of hypothalamus
62
Which nucleus makes oxytocin?
paraventricular nucleus of hypothalamus
63
What is the function of the lateral area of the hypothalamus?
Stimulates hunger. Inhibited by leptin
Destruction -> anorexia, failure to thrive in infants
64
What is the function of the ventromedial area of the hypothalamus?
Satiety, Stimulated by leptin
Destruction (ex craniopharyngioma) --> hyperphagia
65
What is the function of the anterior hypothalamus?
cooling, parasympathetic "cool off"
66
What is the function of the posterior hypothalamus?
heating, sympathetic "get fired up"
67
what is the function of the suprachiasmatic nucleus (SCN) of the hypothalamus?
circadian rhythm
68
What releases melatonin?
pineal gland, stimulated by NE from SCN
69
What causes EOM during REM sleep?
activity of PPRF
70
What is associated with decreased REM sleep?
Alcohol, benzodiazepines, barbituates and NE
71
What is the EEG waveform when awake with eyes open?
Beta (highest frequency, lowest amplitude), alert active mental concentration
72
What is the EEG waveform when awake with eyes closed?
alpha
73
What are the features and the EEG waveform of Non-REM sleep stage N1?
5% of sleep; light sleep, theta waveform
74
What are the features and the EEG waveform of Non-REM sleep stage N2?
45% of sleep, deeper sleep, bruxism (teeth grinding) occurs; waveform: sleep spindles and K complexes
75
What are the features and the EEG waveform of Non-REM sleep stage N3?
25% of sleep, Deepest non-REM sleep (slow-wave sleep); sleepwalking, night terrors and bedwetting occur
Delta waveform (lowest frequency, highest amplitude)
76
What are the features and the EEG waveform of REM sleep?
25% of sleep; Loss of motor tone, increase O2 use, increase variable pulse and blood pressure (dreaming and penile/clitoral tumescence occurs)
beta waveform (highest frequency, lowest amplitude)
77
VPL nucleus of thalamus - what is the input? what info is carried? and what is the final destination?
input: spinothalamic and dorsal columns/medial lemniscus
info: pain, temp (spinothalamic tract); pressure, touch vibration and proprioception (dorsal columns/ medial lemniscus)
destination: primary somatosensory cortex
78
VPM nucleus of thalamus - what is the input? what info is carried? and what is the final destination?
input: Trigeminal and gustatory pathway
info: face sensation and taste
destination: primary somatosensory cortex
79
LGN of thalamus - what is the input? what info is carried? and what is the final destination?
input: CN II
info: vision
destination: calcarine sulcus
80
MGN of thalamus - what is the input? what info is carried? and what is the final destination?
input: Superior olive and inferior colliculus of tectum
info: hearing
destination: auditory cortex of temporal lobe
81
VL nucleus of thalamus - what is the input? what info is carried? and what is the final destination?
input: basal ganglia, cerebellum
info: motor
destination: motor cortex
82
Overly rapid correction of hyponatremia can cause what?
Osmotic demyelination syndrome aka central pontine myelinolysis
83
Overly rapid correction of hypernatremia can cause what?
cerebral edema and herniation
84
What do lateral lesions of the cerebellum cause?
propensity to fall toward ipsilateral side of lesion
85
what do medial lesions of the cerebellum cause?
midline structures like vermal cortex, fastigial nuclie and/or flocculonodular lobe
causes truncal ataxia (wide-based gait), nystagmus, head tilting
86
Athetosis is caused by a lesion where?
Slow writing movement. Lesion in basal ganglia (ex Huntington)
87
What is an essential tremor?
High-frequency tremor with sustained posture, worsens with movement or anxiety; often familial and patients often self-medicate with alcohol which decreases tremor amplitude
88
What is used to treat essential tremors?
beta-blockers, primidone
89
What is hemiballismus and where is the characteristic lesion that causes it?
Sudden wild flailing of 1 arm +/- ipsilateral leg
Characteristic lesion is in CONTRALATERAL subthalamic nucleus (ex lacunar stroke)
90
What is the characteristic lesion that causes intention tremor?
cerebellar dysfunction
91
What symptoms are associated with Parkinson disease?
```
Tremor (pill-rolling tremor at rest)
Rigidity
Akinesia (or bradykinesia)
Postural instability
Shuffling gait
```
92
What are the histological features of Parkinson disease?
Lewy bodies (alpha-synuclein, intracellular eosionohilic inclusions) and loss of dopaminergic neurons (depigmentation) of substantia nigra pars compacta
93
What is the pathophysiology of Huntington disease?
AD trinuclotide repeat of CAG on chromosome 4 "CAG: Caudate loses ACh and GABA"
Causes increased dopamine, decreased GABA and decreased ACh in brain -> neuronal death via NMDA-R binding and glutamate toxicity
94
What are the imaging findings for Huntington disease?
atrophy of caudate nuclei with dilation of frontal horns on MRI
95
What is broca aphasia?
Non-fluent aphasia, intact comprehension and impaired repetition 'Broken boca'
96
Where is Broca area?
inferior frontal gyrus of frontal lobe
97
Where is Wernicke area?
superior temporal gyrus of temporal lobe
98
What is Wernicke aphasia?
Fluent aphasia with impaired comprehension and repetition "wordy but makes no sense"
99
What is conduction aphasia?
poor repetition but fluent speech and intact comprehension. Can be caused by damage to arcuate fasciculus
100
What is global aphasia?
Nonfluent aphasia with impaired comprehension -> damage to Broca, Wernicke and arcuate fasciculus
101
What is transcortical motor aphasia?
Nonfluent aphasia with good comprehension and intact repetition -> understands and can only get repeated words out
102
What is transcortical sensory aphasia?
poor comprehension with fluent speech and intact repetition
103
What is mixed transcortical aphasia?
Nonfluent speech, poor comprehension, intact repetition -> parrot
Broca and Wernicke areas involved; arcuate fasciculus NOT involved
104
amygdala lesion causes what? and what microbe is it associated with?
Kluver-Bucy syndrome - disinhibited behavior (hyperphagia, hypersexuality, hyperorality)
Associated with HSV-1
105
What does a frontal lobe lesion cause?
Disinhibition and deficits in concentration, orientation and judgement
106
What does a lesion in the non-dominant parietal-temporal cortex cause?
hemispatial neglect syndrome (agnosia of contralateral side of world)
107
What does a lesion in the dominant parietal-temporal cortex cause?
Agraphia (inability to write), acalculia (inability to calculate), finger agnosia (inability to distinguish fingers), L-R disorientation
(Gerstmann syndrome)
108
What is caused by lesions to the mammillary bodies?
Wernicke-Korsakoff syndrome - confusion, ophthalmoplegia, ataxia; memory loss (anterograde and retrograde), confabulation, personality changes
109
What are mammillary body lesions associated with?
Wernicke-Korsakoff syndrome is associated with thiamine deficiency and excessive alcohol use; can precipitate from giving glucose without thiamine to a thiamine deficient patient
110
Will cerebellar hemisphere lesions cause ipsilateral or contralateral deficits?
ipsilateral deficits -> intention tremor, limb ataxia, loss of balance, fall toward side of lesion
111
What will a bilateral hippocampus lesion cause?
anterograde amnesia
112
What will a paramedian pontine reticular formation (PPRF) lesion cause?
eyes will look away from side of lesion
113
What will frontal eye fields lesions cause?
eyes look toward lesion
114
Due to watershed zones, what are the consequences of severe hypotension?
upper leg/upper arm weakness (between ACA and MCA) and defects in higher-order visual processing (between MCA and PCA)
115
What is the primary regulator of cerebral perfusion?
PCO2 --> hyperventilation (decreased PCO2) can help decrease ICP in cases of cerebral edema from vasoconstriction
116
How are cerebral perfusion and BP related?
cerebral perfusion pressure (CPP) = mean arterial pressure (MAP) - ICP --> decreases in BP or increases in ICP decrease CPP
117
What causes medial medullary syndrome?
infarct of paramedian branches of Anterior spinal artery (ASA) and vertebral arteries
118
How does Medial medullary syndrome present?
Pyramid (lateral corticospinal tract) - contralateral hemiparesis of upper and lower limbs
Medial lemniscus - decreased contralateral proprioception
Caudal medulla (CN XII) - ipsilateral hypogolssal dysfunction (tongue deviates ipsilaterally)
119
What vessel lesion causes lateral medullary (Wallenberg) syndrome?
Lesion to PICA (posterior inferior cerebellar artery)
120
What are the clinical features of lateral medullary (Wallenberg) syndrome?
* Dysphagia, hoarseness, decrease gag reflex
- vomiting, vertigo, nystagmus
- Decreased pain and temp in ipsilateral face and contralateral body
- ipsilateral Horner syndrome (ptosis, miosis and enophthalmus)
- ataxia and dysmetria
121
What vessel lesion causes lateral pontine syndrome?
AICA (anterior inferior cerebellar artery)
122
What are the clinical features of lateral pontine syndrome?
Paralysis of face, decreased lacrimation, salivation decreased taste from anterior 2/3 of tongue
- vomiting, vertigo, nystagmus
- Decreased pain and temp in ipsilateral face and CONTRALATERAL body
- ataxia and dysmetria
"Facial droop means AICA's pooped"
123
Where would a stroke cause contralateral hemianopia with macular sparing?
PCA - impaired occipital and visual cortex
124
Where would a stroke cause "locked-in syndrome?"
Basilar artery, preserved consciousness and blinking, quadriplegia, loss of voluntary facial and mouth movements
125
What would a lesion in ACom cause?
visual field defects, lesions are typically aneurysms not stroke
126
Where do saccular (berry) aneurysms typically occur?
Most common site is junction of ACom and ACA
127
What is caused by a PCom lesion?
CN III palsy - eye is "down and out" with ptosis and mydriasis. Lesions typically aneurysms, not strokes
128
What is are common complications of saccular (berry) aneurysms?
rupture -> subarachnoid hemorrhage or hemorrhagic stroke
Can cause bitemporal hemianopia via optic chiasm compression
129
What diseases are associated with saccular (berry) aneurysms?
ADPKD, Ehlers-Danlos syndrome
130
What are risk factors for berry aneurysms?
increased age, HTN, smoking, African americans
131
What are Charcot-Bouchard microaneurysms of lenticulostriate vessels associated with?
chronic HTN, affects small vessels - basal ganglia, thalamus
132
What are risk factors for idiopathic intracranial hypertension (pseudotumor cerebri)
woman of childbearing age, excess vitamin A, danazol (hypoestrogenic, hyperandrogenic effects that cause atrophy of the endometrium, which can alleviate the symptoms of endometriosis)
133
How is idiopathic intracranial hypertension (pseudotumor cerebri) treated?
weight loss, acetazolamide (carbonic anhydrase inhibitor), topiramate (antiepileptic), invasive procedures if refractory to treatment
134
What is the difference between communicating and noncommunicating hydrocephalus?
communicating is nonobstructive -> decreased CSF absorption by arachnoid granulations -> increased ICP
Noncommunicating is obstructive -> block of CSF circulation within ventricular system (stenosis of aqueduct for example)
135
What are the symptoms and findings of normal pressure hydrocephalus?
Expansion of ventricles (seen on imaging) distorts fibers of corona radiata -> triad of urinary incontinence (wet), ataxia (wobbly) and cognitive dysfunction (wacky)
136
What is ex vacuo ventromegaly?
Mimics hydrocephalus. Appears to be increase CSF on imaging but due to decreased brain tissue and ICP is normal. Seen in Alzheimer's, advanced HIV, Pick disease..
137
What causes LMN lesions only, due to anterior horn destruction? What are the resulting symptoms?
Poliomyelitis and spinal muscular atrophy (Werdnig-Hoffmann disease). Causes flaccid paralysis
138
What are the spinal cord lesions in MS?
Demeylination mostly in white matter of cervial region; random and asymmetric lesions -> scanning speech, intention tremor, nystagmus
139
What causes amyotrophic lateral sclerosis (ALS)?
Defect in superoxide dismutase 1
140
What are the clinical features of ALS?
combined UMN and LMN deficits with NO sensory or oculomotor deficits
Presents as fasciculations with eventual atrophy and weakness of hands
141
What are the spinal cord lesions that can be caused by tertiary syphilis?
Tabes dorsalis -> from demyelination of dorsal columns and roots -> impaired sensation and proprioception, progressive sensory ataxia (decreased sensation leads to poor coordination)
142
What is Werdnig-Hoffmann disease?
spinal muscular atrophy- Autosomal recessive congenital degeneration of anterior horns of spinal cord -> LMN lesion
"Floppy baby" with hypotonia and tongue fasciculations
143
What is Parinaud syndrome?
paralysis of conjugate vertical gaze due to lesion in superior colliculi damaging MLF
Causes: pineal tumor, MS, stroke
Symptoms:
- vertical gaze palsy
- absent pupillary reflex
- failure of convergence
- wide based gait
144
What things pass through the cavernous sinus?
CN III, IV, V1, VI, sometimes V2, postganglionic sympathetic pupillary fibers, part of internal carotid artery
145
How does cavernous sinus syndrome present and what are possible causes?
Variable ophthalmoplegia (CN III, IV, VI), decreased corneal sensation (V1), Horner syndrome and occasionally decreased maxillary sensation (V2) [Note CN VI most susceptible to damage]
Causes: pituitary tumor mass effect, carotid-cavernous fistula, or cavernous sinus thrombosis from infection
146
What are the findings for the rinne and weber tests with conductive hearing loss?
Rinne test: abnormal (bone>air), Weber test- sounds louder in affected ear
147
What are the findings for the Rinne and Weber tests with sensiorineural hearing loss?
Rinne test: normal (air>bone) but sound diminished in both, just proportionally
Weber test: sounds louder in unaffected ear
148
Lesion of face area of motor cortex or lesion in connection between cortex and facial nucleus causes what symptoms?
UMN lesion - contralateral paralysis of lower face; forehead spared (bilateral UMN innervation)
149
Lesion of CNVII after facial nucleus causes what symptoms?
LMN lesion -> ipsilateral paralysis of upper AND lower face
150
What causes facial nerve palsy?
complete destruction of facial nucleus or efferent fibers (CN VII)
Can occur idiopathically (Bell palsy). Associated with Lyme disease, herpes simplex and less commonly: herpes zoster (Ramsay Hunt syndrome), sarcoidosis, tumors, diabetes
151
What are the symptoms of facial nerve palsy
peripheral ipsilateral facial paralysis with inability to close eye on involved side
152
Which muscles open and close the jaw?
Open jaw: masseter, temporalis, medial pterygoid
Close jaw: later pterygoid
