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firstaid neuro1
firstaid neuro
Question | Answer |
---|---|
what happens in neural development between day 18-day 21 | neural plate+notocord>> neural crest>> neural tube and neural crest cells |
notochord induces overlying ectoderm to differentiate into what? | neuroectoderm and neural plate |
neural plate gives rise to? | neural crest cells and neural tube |
notochord becomes what? | notochord becomes neucleus pulposus of InterVertebralDisk in adult |
name and function of dorsal part of the neural tube? | Alar: sensory |
name and function of ventral part of neural tube? | Basal: Motor |
3 primary vesicle of developing brain? | 1)Forebrain (prosencephalon) 2)Midbrain (mesencephalon) 3)Hindbrain (rhombencephalon) |
5 secondary vesicle? | telencephalon diencephalon mesenchephalon metencephalon myelenchephalon |
forebrain(prosencephalon) gives rise to which secondary vesicle? | Telencephalon and Diencephalon |
midbrain (mesencephalon) gives rise to which secondary vesicle? | Mesencephalon |
hindbrain (rhombincephalon) gives rise to which secondary vesicle? | Metencephaon Myelencephalon |
wall of telencephalon gives rise to? | cerebral hemisphere |
cavity of telencephalon gives rise to? | lateral ventricle |
wall of diencephalon gives rise to ? | thalamus |
cavity of diencephalon gives rise to? | third ventricle |
wall of mesencephalon gives rise to? | midbrain |
cavity of mesencephalon gives rise to? | aqueduct |
wall of metencephalon gives rise to ? | pons and cerebellum |
cavity of metencephalon gives rise to | upper part of 4th ventricle |
wall of myelencephalon gives rise to? | medulla |
cavity of myelencephalon gives rise to ? | lower part of 4th ventricle |
what arises from neuroectoderm? | CNS neuron, ependymal cells,oligodendrocyte, astrocyte (NEOA) |
CNS Neuron arise from | neuroectoderm |
ependymal cells arise from | neuroectoderm |
what does ependymal cells line? | inner lining of ventricle and makes CSF |
oligodendrocyte arises from | neuroectoderm |
astrocyte arise from | neuroectoderm |
PNS neuron arise from | neural crest |
schwann cells arise from | neural crest |
neural crest gives rise to | pns neuron and schwann cells |
Mesoderm gives rise to? | microglia |
microglia are like | macrophages, originate from mesoderm |
what happens in neural tube defect? | neuropore fail to fuse(4th week)>> persistent connection between amniotic cavity and spinal canal |
neural tube defect are associated with what? | low folic acid intake before conception and during pregnancy |
what are lab defect in the neural tube defect? | 1)elevated alpha feto-protein in amniotic fluid and maternal serum 2)increase AChE in amnotic fluid is a confirmatory test |
why AChE can be measured in NTD? | Because fetal AChE in CSF transudate across defect into the amniotic fluid |
what is spina bifida occulta? | Failure of the spinal canal to close but no structural herniation. |
spina bifida occulta is usually seen where? | lower vertebral level |
status of dura in spina bifida occulta? | intact |
spina bifida occulta is associated with what? | tuft of hair or skin dimple at level of bony defect |
what is meningocele? | meninges(not spinal cord) herniate through spinal canal defect. |
What is the level of AFP in Meningocele? | elevated AFP (normal only in spina bifida occulta) |
what is meningomyelocele? | Meninges and spinal cord herniate through spinal canal defect |
Meningomyelocele is seen with what? | Arnold chairi malformation type II |
What is AFP level in Meningomyelocele? | Elevated AFP |
what is anencephaly? | malformation of anterior neural tube resulting in no forebrain, open calvarium("frog like appeareance") |
clinical finding in anencephaly? | increase AFP, Polyhydraminos(no swallowing center in brain) |
why polyhydraminos in anencephaly? | because no swallowing center in brain |
anencephaly is associated with what? | maternal diabetes type 1 |
forebrain anomalies? | anencephaly and holoprosencephaly |
in what week holoprosencephaly seen? | 5-6 wk |
etiology of holoprosencephaly? | mutation in sonic hedgehog signaling pathway |
moderate form of holoprosencephaly has what? | cleft lip & palate / holoprosencephaly also seen in patau-trisomy 13 and fetal alcohol syndrome |
severe form of holoprosencephaly has what? | cyclopia |
what are Posterior fossa malformations? | arnold chairi malformation and dandy walker |
what is arnold chairi malformation? | herniation of cerebellar tonsils and vermis through foramen magnum with aquductal stenosis and hydrocephalus |
arnold chairi malformation is associated with what? | lumbosacral myelomeningocele and syringomyelia |
paralysis of arnold chairi at what level? | below the defect |
what is Dandy walker syndrome? | agenesis of cerebellar vermis and splenium with cystic enlargement of 4th ventricle |
which fossa is filled by dandy walker? | enlarged posterior fossa |
Dandy walker syndrome is associated with what? | non communicating hydrocephalus and spinabifida |
what is syringomyelia? | cystic cavity within the spinal cord (if central canal >> hydromyelia) |
which fibers of spinal cord are damaged in syringomyelia? | anterior spinal commisural fiber |
syringomyelia is associated with what? | Arnold chiari malformation type II, trauma and tumor |
what is Arnold chiary malformation type I? | >3-5mm cerebellar tonsilar ectopia / Manifests and headache and cerebellar symptoms |
where does syringomyelia most commonly occur? | C8-T1 |
Clinical feature of syringomyelia? | Cape like - bilateral loss of pain and temperature sensation in upper extremities(fine touch sensation is preserved) |
syringomyelia may cause what syndrome? | horner syndrome (Ptosis, anhydrosis, miosis) |
which embryonic structure forms tongue? | 1st and 2nd branchial arches form anterior 2/3rd of tongue / 3rd and 4th branchial arches form posterior 1/3rd of tongue |
sensation of tongue? | General sensation (9) and taste sensation (9) - post 1/3rd (99) General sensation (5) and taste sensation (7) - anterior 1/3rd (57) |
taste sensation is carried via ? | CN 7(anterior 2/3rd) ,9(posterior 1/3rd) , 10- extremely posterior (solitary nucleus) |
pain sensation in tongue is carried via? | CN V3 - anterior (53), 9 -posterior, 10 - extremely posterior |
motor innervation in tongue? | CN 10 ,12 |
muscle of tongue is derived from? | occipital myotomes(somatomeres) |
Motor innervation to tongue specifically? | Motor innervation is via CN 12 to hypoglossus, genioglossus, styloglossus via CN 10 to palatoglossus |
function of hypoglossus? | retract and depresses the tongue |
function of genioglossus? | protrude the tongue |
function of styloglossus? | draws side of tongue upward to create trough for swalloing |
function of palatoglossus? | elevate posterior tongue during swallowing |
what are the signal transmitting cells of nervous system? | neurons |
how often do neurons divide? | permanent cells - do not divide in adulthood |
what are neurons? | signal relaying cells with dendrites(receive input), cell body and axon(sends output) |
what do dendrites do? | receive input |
what do axons do? | sends output |
cell body and dendrite can be stained how? | stained via nissl substance (stains RER) |
why axons not stained? | no RER in the axon |
what happens if axon is injured? | it undergoes wallerian degeneration |
what is the work of wallerian degeneration? | allows for potential regeneration of axon(if in PNS) |
function of axon? | physical Support, Repair, K+ metabolism, removal of excess neurotransmitter, component of BBB, glycogen fuel reserve buffer ( SRK is BG Removing excess neurotransmitter) |
how do astrocyte respond to neural injury? | by Reactive gliosis |
what is the marker for astocyte? | GFAP |
astrocyte is derived from what? | neuroectoderm |
what is microglia? | phagocytic scavenger cell of the neruvous system (mesodermal, mononuclear origin) |
germ layer origin of microglia? | mesoderm |
how do microglia stain with nissl stain? | not readily discernible with nissl stain |
what happens to microglia in HIV? | HIV inected microglia fuse to form giant cell in the CNS |
what is the function of myelin? | wraps and insulates axons : 1) increase space constant 2) increase conduction velocity |
fuction (particularly increase condution velocity) of myelin result in what action? | saltatory conduction of action potential between node of ranvier, where there are high concentration of sodium channel |
what makes myelin in CNS? | oligodendrocyte |
what makes myelin in PNS? | schwann cells |
each schwann cell myelinate how many PNS axon? | 1 PNS axon |
function of schwann cell? | promotes axonal regeneration |
schwann cell derived from where? | neural crest |
proper function of schwann cell? | increase condution velocity via saltatory conduction at node of Ranvier, where there is high concentration of Na+ channel |
schwann cells are destroyed in what disease? | Guillian barre syndrome |
where is vestibular schwanoma(acoustic neuroma) located? | located in the internal acoustic meatus(CN VIII) |
if acoustic neuroma is bilateral what is it associated with? | associated with Neurofibromatosis type 2 |
each oligodendrocyte myelinate how many CNS axon? | multiple axon (upto 30) |
what is the predominant glial cell in white matter? | oligodendrocyte |
how does oligodendroglia appear on H & E? | fried egg apprearenace |
what are the disease if oligodendroglia is injured? | MS / Progressive multifocal leuckoencephalopathy (PML) / leukodystrophies |
what are the 2 type of free nerve ending? | C and A delta |
what type of fibers are C fibers? | slow, unmyelinated fibers |
what type of fibers are A delta fibers? | fast myelinated fibers |
what are the location of A delta and C fibers? | all skin, epidermis, some viscera |
what are the senses carried by A delta and C fibers? | pain and temperature |
what type of fibers are meissner corpuscles? | large myelinated fibers that quickly adapt |
what is the location of meissners corpuscles? | glabrous(hairless) skin |
what are the senses carried by Meissners corpuscle? | Dynamic, fine/ light touch and position sense |
what are pacinian corpuscles? | large myelinated fibers that adapt quickly |
waht are the location of pacinian corpuscles? | deep skin layers, ligaments and joints |
waht are the senses carried by pacinian corpuscle? | vibration and pressure |
what are merkel discs? | large myelinated fibers that adapt slowly |
what are the location of merkel discs? | finger tip, superficial skin |
what are the senses carried by merkel discs? | pressure and deep static touch(eg: shapes, edges), position |
what does endoneurium invest? | invests single nerve fiber layers |
endoneurial inflammatory infiltrate present in? | GBS |
what does perineurium(permeable barrier) surround? | surrounds fascicle of nerve fibers |
what is to be rejoined for limb attachment during microsurgery? | perineurium |
what is epineurium? | dense connective tissue that surrounds entire nerve(fascicle and blood vessels) |
what is ruffini corpuscle? | dendritic ending with capsule that adapt slowly |
location of ruffini corpuscle | finger tip , joints |
what are the senses carried by ruffini corpuscle? | Pressure, slippage of objects along surface of skin, joint angle change |
what is the location of synthesis of acetylcholine neurotransmitter? | Basal nucleus of Meynert |
what is the location of synthesis of dopamine neurotransmitter | ventral tegmentum, SNpc |
what is the location of synthesis of GABA neurotransmitter | nucleus accumbens |
what is the location of synthesis of norepinephrine neurotransmitter | locus ceruleus |
what is the location of synthesis of serotonin neurotransmitter | raphe nucleus |
function of BBB? | preventing circulating blood substances form entering the CSF/CNS |
what is BBB formed from? | 1) tight junction between non-fenestrated Capilary endothelial cells 2)Basement membrane 3)Astrocyte foot processes @ABC |
how does glucose and AA cross BBB? | cross by carried mediated transport mechanism |
how does non-polar or lipid soluble substance cross BBB? | cross rapidly via diffusion |
infarction and neoplasm destroys endothelial cell tight junction and cause? | vasogenic edema |
other notable barriers? | blood testis barrier AND maternal fetal blood barrier of placenta |
function of hypothalamus? | TAN-HATS 1) thirst and water balance 2) adenohypophysis control( regulate ant pituitary) 3) neurohypophysis release hormones produced in the hypothalamus 4) hunger 5) autonomic regulation 6) temperature regulation 7) sexual urges |
what does supraoptic nucleus of hypothalamus make? | ADH |
what does paraventricular nucleus of hypothalamus make? | Oxytocin |
what does hypothalamus make? | ADH: by Supraoptic nucleus oxytocin: by paraventricluar nucleus |
what carries ADH and oxytocin? | neurophysins |
where does neurophysins carry ADH and oxytocin? | posterior pitutary then stored and released |
what is the function of lateral area of hypothalamus ? | mediates hunger |
what happen if the lateral area of hypothalamus is destroyed? | anorexia , failure to thrive(infant) { one becomes slimmer :p) |
lateral area of hypothalamus is stimulated by? | ghrelin |
lateral area of hypothalamus is inhibited by? | leptin |
what is the function of ventromedial area of hypothalamus ? | mediates satiety |
what happens if ventromedial area of hypothalamus is destroyed? | destruction(eg :craniopharyngioma) causes hyperphagia {grow fat} |
ventromedial area of hypothalamus is stimulated by? | leptin |
anterior hypothalamus function? | cooling and parasympathetic |
posterior hypothalamus function? | heating and sympathetic |
suprachaismatic nucleus of hypothalamus function? | circadian rhythm |
sleep cycle is regulated by? | circadian rhythm |
circadian rhythm is driven by? | Suprachaiasmatic nucleus of hypothalamus |
circadian rhythm controls nocturnal release of ? | ACTH, Prolactin, melatonin and norepinephrine (@MAPN) |
sequence of melatonin secretion by SCN? | suprachaiasmatic nucleus>> norepinephrine release >> pineal gland>> melatonin |
suprachaismatic nucleus is regulated by? | environment(eg; light) |
2 stage of sleep? | REM and NREM |
extraocular movement occurs during which sleep? | REM sleep |
extraocular movement during REM sleep due to ? | activity of PPRF(paramedian pontine reticular formation/conjugate gaze center) |
REM sleep occurs every ------ minute? | 90 mins. duration increase throug out the night |
what is associated with decrease REM sleep and delta wave sleep? | alcohol, benzodiazepines and barbiturates decreases both BUT norepinephrine decreases REM sleep(no delta wave) |
what does DDAVP mimic? | ADH (imipramine may also be used but not used due to advese side effect) |
what is used for night terror and sleepwalking? | benzodiazepines |
sleep stage AWAKE(eyes open). what does it signify? | alert and active mental concentration |
what eeg is seen in AWAKE(eyes open) condition? | beta( highest frequency and lowest amplitude) |
sleep stage AWAKE (eyes closed). what eeg wave is seen? | alpha |
what is Non REM sleep stage N1? | it is light sleep |
what eeg is seen in Non REM sleep stage N1? | theta |
what is Non REM sleep stage N2? | deeper sleep |
what conditon is seen in Non REM sleep stage N2? | bruxism |
what eeg is seen in Non REM sleep stage N2? | sleep spindle and K complexes |
what is Non REM sleep stage N3? | deepest non REM sleep(slow wave sleep) |
what condition is seen in Non REM sleep stage N3? | sleepwalking, night terrors and bedwetting |
what eeg pattern is seen in Non REM sleep stage N3? | delta(lowest frequency, hightest amplitude) |
what happens in REM sleep? | 1) loss of motor tone 2) increase brain use 3) increase and variable pulse and BP |
when does REM sleep occur? | when dreaming, nightmares and penile/clitoral tumescence( engorgement) occur |
what sleep serves as memory processing ? | REM sleep |
what eeg pattern is seen in REM sleep? | Beta |
pnemonic for eeg waveform of sleep? | BATS Drink Blood |
what are the input of cerebellum? | 1) contralateral cortex via middle cerebellar peduncle 2) ipsilateral propioceptive information via inferior cerebellar peduncle from spinal cord |
what are the input nerve of cerebellum? | climbing and mosey fibers |
what are the output nerve of cerebellum? | purkinje cells >> deep nuclei of cerebellum >> contralateral cortex via the superior cerebellar peduncle |
what are the deep nuclei (lateral >> medial) of cerebellum? | dentate , emboliform, globose, fastigial ( dont eat greasy foods) |
what happens if there is lateral lesion (injury) of cerebellum? | propensity to fall towards injured (ipsilateral) side |
what happens if there is midline lesion of the cerebellum? (vermal cortex , fastigial nuclei and flocculonodular lobe) | results in truncal ataxia, nystagmus, head tilting, cerebellar gait and deficit in truncal co-ordination |
midline lesion of the cerebellum results in? | bilateral motor deficits affecting axail and proximal limb musculature |
function of basal ganglia? | 1) voluntary movement 2) postural adjustments |
what does basal ganglia receive? | receives cortical input |
which feedback does basal ganglia provide and where and why? | negative feedback to the cortex to modulate movement |
putamen (motor) + caudate (cognition) | straiatum |
globus pallidus + putamen | lentiform |
excitatoty pathway | cortical input stimulate the striatum >> stimulate the release of GABA which disinhibit the thalamus via GPi/SNr (increase motion) |
inhibitory pathway | cortical input stimulate the striatum >> disinhibits STN via GPe and STN stumulates GPi/SNr to inhibit the thalamus (decrease motion) |
dopamine binds to D1 receptor and causes what? | stimulate the excitatory pathway |
dopamine binds to D2 receptor and causes what? | inhibiting the inhibiroty pathway ( increase motion) |