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61 Cards in this Set
- Front
- Back
What are the most important factors of CNS malformations?
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Timing of lesion & what is going on at that time
...not so much the agent |
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Name the 6 stages of Neurological maturation
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1) Neurogenesis
2) Apoptosis 3) Neuronal Migration 4) Cytodifferentiation (axon and dendritic growth) 5) Synpatogenesis 6) Myelination of axons |
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When is neurogenesis completed?
Name the two regions that exceptions to this and are capable of regeneration postnatally? |
By birth
1) External granular layer of the cerebellum 2) Primary olfactory neurons |
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Difference b/w mature neuron and neurblast (2)?
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1) electrical activity
2) secratory fxn only neurons have both |
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Pattern neuronal migration of cerebrum?...cerebellum?
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cerebrum: from ventricles out
cerebellum: from surface in |
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Failure of the mechanism fo apoptosis results in? Name of disease?
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Spinal muscluar atrophy
Werdnig-Hoffmann Dz -hereditary dz, infants severely weak and developmentally delayted but of normal intelligence |
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Failure of glial apoptosis results in?
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Agenesis of corpus callosum
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What cells guide neurons to their mature sites during migration?
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Radial glial fibers
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Cytodifferentiation involves the formation of what 2 things?
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Axons - cone growth
Dendrites - spine growth |
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Is the nerve cell capable of reorienting its axon? Dendritic tree?
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axons = yes
dendrites = no |
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Down syndrome results from defect in what process
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Faulty synaptogenesis (and perhaps cytodifferentiation...script and outline contradict)
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When is the most active period of proliferation of dendritic spines and synapse formation in the cerebral cortex?
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After 28 weeks
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When does the myelination of the optic begin and end?
corpus callosum? ending of frontotemporal association bundle |
optic n = birth to 3 months
corpus c = 4 months to 16 years frontotemporal = ends at **32 years** |
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Hypothyroidism causes what neuronal defect?
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Delayed myelination
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Neural tube defects are from genetic or environmental origins?
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BOTH - multifactorial
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Major events of dorsal induction (Neuraltion)? Timing?
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Neural tube closure - Skull & spinal column
3-4 weeks |
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Cranioraischisis
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incomplete closure of the skull AND spinal column (neural plate open throughout its length)
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Ancephaly is a defect in?
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Dorsal Induction - still have brainstem
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Myelocahcisis
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Spinal cord remains open througout its length
-kinda like a cranioraischisis w/out the skull defect |
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Common effect of myelomeningocele?
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Hydrocephalus (90% affected)
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Major events of Ventral induction (Neuraltion)? Timing?
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Cleavage of prosencephalon - face and brain formation
5-6 weeks |
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Micrencephaly is what?
a defect in? occurs when Associated with? |
Small brain
Neuronal Proliferation (neurogenesis) 2-4 months Polymicroglia (migrational defect - small irregular gyri) |
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Holoprosencephaly is a defect in?
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Ventral induction
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Porencephaly
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cavity that communicates between a lateral ventricle and subarachnoid space
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More severe form of porencephaly
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Schizecephaly
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Schizecephaly caused by?
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Stroke in MCA in early pregnancy
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What is Lissencephaly?
Defect in? Baby's signs of having? |
Absence of sulcal adn gyral development (SMOOTH BRAIN)
Migration 1)lack of eye contact 2)stiffness 3)seizures 4)developmental delays |
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Pachygyria?
Defect in? Associated symptoms? |
Thick gyri
Error in migration Seizures |
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Neuronal heteropias (periventricular heteropias)? Unique propertycompared to other migrational disorders?
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Displaced masses of gray matte within white matter - Seizures
Unilateral (nonsymmetric) developement |
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Leukodystrophies are a defect in?
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Myelination
White matter distrubances |
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Brain accounts for what percent of total body weight?
What percent of Cardiac Output? |
2.5%
15% |
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What is the main blood supply for the suptratentorial tissue?
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Internal carotid system
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What is the main blood supply for the subtentorial nervous tissue?
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Vertebro-basilar system
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Internal Carotid system (supratentorial) consists of what vessels?
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long circumferential vessels (ACA, MCA, PCA) = supply cortex
short circumferential vessels = supply Thalamus, Internal Capsule, & Basal Ganglia Paramedian vessels = base of brain near midline |
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Vertebro-basilar system (infratentorial) consists of what arteries?
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Superior cerebellar artery
AICA PICA |
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Ophthalmic artery anastomoses?
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External and Internal carotids
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Leptomengeal vessels anastomose?
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branches of the major cerebral arteries
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Intraparenchymal vessels anastomose?
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short and long circumferential vessels
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Neural parenchyma that receive input from the distal portions of two major arteries
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Watershed region
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T/F In contrast to the arterial system, the venous drainage of the CNS is less often a cause of CNS pathology
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True
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Final common pathway of superficial and deep CNS veins
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Dural sinuses
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What is the most common pathologic event in the CNS?
leads to the production of? |
Arterial cerebral (ischemic) infarction
Pale (white) infarcts |
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Occurrence and extent of cerebral infarction is determine by what three basic factors
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1) Site of arterial occlusion
2) Rapidity of arterial occlusion 3) The presence or absence of collateral circulation |
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Describe the temporal evolution of an infarct (3)
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1) Acute (1 day - 1 week): soft and edematous with blurring of anatomic detail
2) Subacute (1 week - 1 month): obvious tissue destruction and liquefactive necrosis 3) Chronic (>1 month): damaged tissue ahs been phagocytized and there is cavitation with surrounding gliosis |
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Microscopic temporal evolution of cerebral infarcts?
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1) 0-48 hours: chromatolysis and shrunken eosinophilic neurons
2) 24-72 hours: neuronal cell necrosis and acute inflammatory response 3) 3-5 days: influx of mononuclear cells, begin to phagocytize necrotic debris 4) 1-2 weeks: vascular proliferation and reactive astrocytosis 5) >1 month: necrotic tissue will be comletely removed and cystic cavity surrounded by a glial scar will be formed |
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Lacunar infarcts are found where? Size by definition?
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Basal ganglia and Pons
< 1.5 cm in diameter |
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Most common cause of thrombotic occlusion?
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Atherosclerosis
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Artherosclerosis typically affects what?
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Large arterial vessls at the base of brain (Circle of Willis)
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Second cause of thrombotic occlusion?
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Group of diseases collecively termed ARTERITIS
-usually affect multiple, SMALL-medium sized arteries and cause focal hemorrhages Examples: collagen-vascular disease, fungal infections, TB, syphilis, sarcoidosis, and meningitis |
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Third cause of thrombotic occlusion?
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Systemic disease - Sickle cell anemia & polycythemia
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Herniation of what results in fatal Duret hemorrhages?
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Herniation of temporal cortex (uncus) under the tentorium
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What event may occur after Subarachnoid hemorrhages (or meningitis) and produce cerebral infarctions?
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Vascular spasms
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Non-occlusive causes of arterial cerebral infarction (3)? What area is particularly susceptible?
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1) Systemic hypotension
2) Cardiac arrest 3) Septic shock Watershed zone |
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Non-occlusive causes of arterial cerebral infarction?.. with selecive neuronal damage where?
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Hypoxia/hypoglycemia
Selective neuron loss.. 1)cerebral cortical neurons (esp layers 3 & 5) 2)pyramidal neurons in the hippocampus 3)Purkinje cells of cerebellum (Bergmann gliosis) |
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Hemorrhagic infarct from venous thrombosis = ?
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Occlusion fo VEINS
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Interacerebral hemorrhage secondary to hypertension referred to as? Occurs where?
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Charcot-Couchard aneurysms
Short circumferential vessels supplying Basal Ganglia (80%), pons (10%) |
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Subdural hemorrhage of Perinatal period usually caused by (3)?
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Forceps delivery
Cephalopelvic disproportion Breech deliveries Subdural hemorrahge is rarely a cause of infant death |
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Which Perinatal hemorrhage is fairly common but clinically silent? If extensive then?
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Subarachnoid Hemorrhage
may result in obstruction of arachnoid granulations (cause hydrocephalus) |
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Perinatal CNS vascular problem that is a frequent cause of death in premature infants?
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Intraventricular hemorrhage (IVH) **(esp 26-28 weekers)
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When you see 1)Alteration of consciousness 2)Hemiplegia 3)3rd nerve palsy think..
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Uncla Herneation
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Type of hemorrhage where blood spreads and sticks intimately w/ brain
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SAH
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