Neuro 2 Flashcards by Kaitlyn Johnson

wall of neural tube is composed of neuroepithelial cells that continue to divide giving rise to

neuronal, ependymal, and glial progenitor cells

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what are the 3 layers of embryonic neural tube

ventricular zone (germinal layer)
mantle layer
marginal layer

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germinal layer composed of

activating, dividing cells; various cells born that migrate away

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what zone is closest to the neural canal

ventricular zone

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ependymal cells form what

a simple cuboidal epithelium lining that remains attached to the internal limiting membrane of the cavities of the CNS

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ependymal cells persist in adult to line

ventricles and central canal of spinal cord; form choroid plexus

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germinal layer active cell division; dividing cells move to

mantle layer

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what is the intermediate zone

the mantle layer

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what is the mantle body composed of cell bodies of

proliferating neuroepithelial cells (immature neurons and glial cells)

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mantle layer ultimately becomes

gray matter of CNS

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What is the outer zone

marginal layer

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what is the marginal layer composed of

axon processes of developing neurons (primary component myelinated axons)

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marginal layer becomes

white matter of CNS

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Neural crest cells become

GSA neurons
postganglionic GVE neurons (symp and parasymp)
PNS glial cells
melanocytes
adrenal chromaffin cells (epinephrine)
arachnoid and pia mater
various other non-neuronal cells

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left and right dorsal thickenings of mantle layer become

alar plate

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alar plate becomes

interneurons,sensory relay neurons

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left and right ventral thickenings of mantle layer become

basal plate

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basal plate becomes

motor neurons

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left and right longitudinal grooves form on inner wall of neural canal and become

sulcus limitans

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sulcus limitans is the boundary between

dorsal sensory alar plate and ventral motor plate

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alar and basal plates do what

expand and fuse forming characteristic butterfly-shaped gray matter of spinal cord

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alar plate becomes ______ horns

dorsal horns

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basal plate becomes ______ horns

ventral and intermediate horns

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sulci of neural canal eventually disappear and canal

reduces in diameter to become central canal

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right and left sides remain ___ on the surface

demarcated

dorsal median groove

shallow depression

ventral fissure

deep groove

motor neuron axons will emerge ____

ventral roots

GVE migrate to

junction of alar and basal plates (intermediolateral gray horn) and move to target

what is the target at this time

somites!

fusing and reshaping of somites creates

limbs

gsa neuron processes are ___ derived

neural crest derived

gsa neuron processes grow into

dorsal roots and out spinal nerve

cell bodies of gsa

dorsal root ganglion

dendrites to receptor become

spinal nerve

axons become

dorsal root

early brain development require

closure of rostral neuropore to be normal

3 dilations form at ____ end of neural tube

rostral end

the rostral end of neural tube is

primary vesicles (follows closure of neural tube

what are the 3 dilations

proencephalon mesencephalon rhombencephalon

2 bends or flexures develop

cervical flexure and cephalic flexure

cervical flexure between

rhombencephalon and developing spinal cord

cephalic flexure occurs in

mesenchephalon

cervical flexure persists in what species

in all species as accomodation of head and neck

cephalic flexure temporary in

quadrapeds

cephalic flexure persists in

bipeds (primates)

prosencephalon and rhombfencephalon subdivide forming

a total of 5 secondary vesciles

prosencephalon divides into

telencephalon and diencephalon

telencephalon becomes

cerebral cortex and basal ganglia and hippocampus

diencephalon becomes

thalamus, hypothalamus, retina

rhombencephalon divides into

metencephalon and mylencephalon

metencephalon becomes

pons and cerebellum

mylencephalon

medulla oblongata

pontine flexure forms and begins separation of

metencephalon into pons and cerebellum

neural canal expands and persists as _____

ventricular system within each secondary vesicle

neural canal lined by

ependymal cells

telencephalon contains

lateral ventricles

diencephalon contains

3rd ventricle

mesencephalon becomes

mesencephalic aqueduct

metencephalon contains

4th ventricle

myelencephalon contains

4th ventricle

csf is produced by

choroid plexus (ependymal cell origin)

csf production is _____ independent

pressure

csf produced by

lateral, 3rd, 4th ventricles

organization of brain development

initial pattern similar to spinal cord with alar and basal plates (alar sensory, basal motor)

in brainstem, as progress dorsal aspect thins,

alar plate moves laterally pushing basal plate medially

more _____ parts lose this organization

rostral

neural tube fails to develop normally along some part of its

length

structure ____ to neurotube rquire neurotube to develop normally

dorsal

spina bifida

failure to close caudal end of neural tube in what will beocme spinal cord or rupture of caudal neuropore (defect in primary neurulation)

failure to close cranial neural tube affects

the brain and head

failure to close entire neural tube is a lethal condition called

cranioarchischisis

spina bifida occulta is a defect in

vertebral arch in which no material extends out of vertebral canal; skin covers defect;

what neurological symptoms do you see with spina bifida occulta

minimal to none

spina bfida + meningocoele

defect in vertebral arch; CSF fill sac of meninges protrude, no spinal cord tissues protrude; most covered by skin

what neurological signs do you see with spina bifida +meningocoele

minimal

muscle mass in spina bifida + meningocoele

no muscle mass where defect is

spina bifida + meningomyelocoele

defect in vertebral arch, meninges & spinal cord bulge out of vertebral canal; CSF filled sac of meninges with disorganized spinal cord tissue protrude; most NOT covered by skin;

spina bifida + meningomyelocoele neurological sings

disorganized neural tissue and neurologic damage to nerve roots; moderate to severe neurological symptoms

defect in primary neurulation results in

tail - less; can have urinary and fecal incontinence if sacral cord affected

anencephaly

lethal conditio in which calvarie (bones of skull that surround brain) fails to form around brain;

in ancephaly what happens to the forebrain

fetal forebrain stops developing and remains in contact with amniotic fluid and subsequently degenerates (prosencephalon or forebrain and meninges in region is absent)

exencephaly

defect in skull, brain tissue extends through defect; no skin or meninges cover brain tissue

meningocoele

defect in skull, meninges extend through defect; CSF filled sac of meninges, no brain tissue; may be covered by skin

menigoencephalocoele

defect in skull, meniges and brain tissue extend through defect; brain and CSF filled sac of meninges; may be covered by skin

hydrocephalus

abnormal accumulation of cerebrospinal fluid in cranial cavity within ventricular system and /or subarachnoid space

how does hydrocephalus occur

can be acquired or congenital

what happens in hydrocephalus

disrupt circulation of CSF (obstruction leads to accumulation); elevated CSF pressure compresses neurons (neuron death if pressure not relieved)

if increased pressure occurs prior to closure of sutures

skull expands (domed appearance) on top of head; skull cant dome once sutures fuse

what is the most common obstruction site

mesencephalic aqueduct

cerebellar hypoplasia (atrophy, abiotrophy) is often a rsult of

viral infection during late fetal development at time of rapid cel division (growth)

what viruses can cause this

feline panleukopenia virus (feline distemper) bovine viral diarrhea virus 1st affects dam, then crosses placenta and invades developing brain of fetus

ddividing cells kille dby

virus (number of cells lost=severity of symptoms)

cerebellar ataxia occurs when

born with too few cells in cerebellum

this causes

disrupt rate, range and force of motion

what sings can you see

over reaching, over-stepping, high stepping; falling under reahing, short stepping; falling postures to compensate poor balance and motion control (broad based stance)