ch 8 - development of the nervous system

3 developmental stages in utero

pre-embryonic, embryonic, fetal

pre-embryonic time frame

conception to day 14

embryonic time frame

day 15 to the end of week 8

fetal time frame

week 8 to birth

pre-embryonic stage

• a ____ cell begins ___ as it moves down the ____ tube into the cavity of the ____

• ____ cell division

• the inner cell mass develops into ____ (has ____ layers, ____ and ____)

• but _____ layers are formed: ___, ___, ___

single, cell division, uterine, uterus, rapid, embryonic disc, 2, ectoderm, endoderm, 3, ectoderm, endoderm, mesoderm

embryonic stage

• ____ are formed

• ectoderm develops into _____, ____, ____

• mesoderm develops into ____, ____, ____, ____

• endoderm develops into ____, ____, _____

organs

sensory organs, epidermis, nervous system

dermis, muscles, skeleton, excretory/circulatory systems

gut, liver, pancreas, respiratory system

fetal stage

• ______ develops more fully

• _____ begins

nervous system, myelination

two phases of the embryonic stage

neural tube formation, brain formation

neural tube formation

• time frame = _____

• ____ forms on the surface of the embryo extending from ____ to ____

• when edges of folds touch, ____ is formed

• closure occurs ___ in the future cervical region

• ____ are the open ends, close by day ____

• ____ forms when the cells adjacent to the neural tube ___

• ____ and ___ move inside the embryo

days 18-26, neural plate, head, tail, neural tube, 1st, neuropores, 30, neural crest, separate, neural tube, crest

formation of the neural tube

• by day ____ neural tube differentiates into _____

  • inner layer = ____ matter

  • outer layer = _____ matter

26, two concentric rings, gray, white

as the neural tube closes, the adjacent mesoderm divides into ____

• 3 parts: _____

somites, anteromedial, posteriomedial, lateral

3 parts of somites

anteriomedial: part (____) that becomes ____ and ____

posteriomedial: part (____) that becomes _____

lateral: part (____) that becomes _____

sclerotome, vertebrae, skull, myotome, skeletal muscle, dermatome, dermis

as the cells of the inner layer of neural tube ____, ____ forms on each side separating tube into ____ and ____ sections

proliferate, grooves, ventral, dorsal

neural tube sections

• ventral: ____ plate

• dorsal: ____ plate

motor, association

until ___ fetal month, spinal cord segments correspond to adjacent ____, then the ____ grows faster than the ____

3rd, vertebra, vertebral column, cord

name for the end of the spinal cord

conus medullaris

bundle of nerve roots that extend form the end of the spinal cord

cauda equina

brain formation begins on day ____

28

brain formation

hindbrain: becomes _____

medulla, pons, cerebellum

brain formation

mid brain: ____ and ____ its name through development

enlargement, retains

brain formation

central canal: becomes the _____ in the midbrain, connecting the ____ ventricles

cerebral aquaduct, 3rd and 4th

brain formation

posterior region of the forebrain: becomes _____

diencephalon

brain formation

anterior part of forebrain: becomes _____

telencephalon: becomes ______

telencephalon, cerebral hemishperes

development during fetal stage

____ area of hemispheres dont grow as much as other areas

surfaces of ____ and ____ hemispheres being to ____, creating ____ and ____

lateral, cerebral, cerebellar, fold, sulci, gyri

celluar level development during fetal stage

-neurons ____ after migrating to their final location

-function of each neuron depends on the ____ of the brain where it migrates

-____ emerges from the neuron cell body, the end expands to from a _____

differentiate, area, process, growth cone

muscle fiber type is dependent on ____

• fast twitch muscle can be converted to slow if innervated by a _____

• slow twitch muscle can be converted to fast if innervated by a ____

innevation, slow lower motor neuron, fast lower motor neuron

early in development, ___ of neurons formed die due to ____

half, inactive

myelination begins in the ____ fetal month and is completed by the end of the ___ year of life

4th, 3rd

____: nervous system damage occurring early is not evident until the damaged system becomes ____

growing into deficit, functional

the central nervous system is most susceptible to major malformation between day ___ and week ___; which would be ___ to ____ stage

14, 20, embryonic, fetal

neural tube deficit where formation of a brainstem without cerebral and cerebellar hemispheres

anencephaly

anencephaly

• occurs when the cranial end of the neural tube ____ and the ____ does not develop

remains open, forebrain

neural tube defects where there is a deformity in the hindbrain

arnold-chiari malformation

arnold-chiari malformation

• type 1

  • often ____

  • cerebellar tonsils ____ into ____

  • ____ and ____ are small and malformed

asymptomatic, herniate, vertebral canal, pons, medulla

arnold-chiari malformation

• type 2

  • signs present in ____

  • malformation of ____ and ____

  • causes progressice hydrocephalis, ____ of the SCM, deafness, bilateral weakness of ____, and facial weakness

infancy, brainstem, cerebellum, paralysis, lateral eye movement

neural tube defect that results when inferior neuropore doesn’t close

spina bifida

3 types of spina bifida

meningocele, myelomeningocele, myeloschisis

spina bifida - meingocele

• ____ protrude through bony defect

meninges

spina bifida - myelomeningocele

• ____ and ___ outside the body

neural tissue, meninges

spina bifida - myeloschisis

• malformed ____ open to the surface of the ____

• most ____

spinal cord, body, severe

potential causes of spina bifida

• increased maternal ___

• _____ meds

• inadequate ___

alchohol, antiseizure, folic acid

when the spinal cod adheres to lower vertebra causing dermatomal and myotomal deficits in lower limbs

tethered spinal cord

higher incidence of _____ in those with spina bifida

tethered spinal cord

disorder where motor neurons degerate at early age

spinal muscular atrophy

spinal muscular atrophy

• most common genetic defect is deletion of the _____ gene

  • there is a ____

survival motor neuron, cure

disorder that causes CNS deficits and facial anomalies

fetal alcohol syndrome, cocaine-affected nervous system

exposure to alcohol in utero can cause ____ and ____ problems

impulsivity, learning

movement disorder caused by permanent nonprogressive damage of the developing brain

cerebral palsy

cerebral palsy effects

• ____, somatosensory, ___, auditory, and ____ deficits

• ____ is common

• nervous system damage is not ___, but new problems may appear as they develop

cognitive, visual, speech, growing into deficit, progressive

5 types of cerebral palsy

ataxic, hypotonic, spastic, dyskinetic, mixed

cerebral palsy where there is incoordination and shaking during voluntary movement

ataxic

ataxic cerebral palsy: lesion = _____

cerebellum

the 4 types of cerebral palsy that have abnormal muscle tone

hypotonic, spastic, dyskinetic, mixed

cerebral palsy where there is very little resistance to passive stretch. little or no ability to actively move

hypotonic

site of damage for hypotonic cerebral palsy = ____

unknown

most common type of cerebral palsy

spastic

cerebral palsy where there is neural resistance to external movement, increases with speed of stretch

spastic

3 types of spastic cerebral palsy

diplegia, hemiplegia, quadriplegia

spastic cerebral palsy

diplegia: ____

hemiplegia: _____

quadriplegia: _____

both legs, one side of the body, all limbs

spastic cerebral palsy

-____ matter damage

-____% of children with CP

-reduced reciprocal inhibition of ____

white, 80, antagonist

cerebral palsy where the tone varies from hypotonia to hypertonia

dyskinetic

site of damage of dyskinetic cerebral palsy = _____

basal ganglia

cerebral palsy where there is more than one type of abnormal movement coexist in one individual

mixed

____ during birth is rarely a cause of cerebral palsy

hypoxia

80% of cerebral palsy cases result from events that occur ____ labor

before

abusive head trauma (shaken baby syndrome) signs

• partial or complete ____

• cognitive and ____ deficits

• motor signs similar to developmental delay of ____

blindness, behavorial, cerebral palsy

autism spectrum disorders - typical signs

• have limited ____

• have impaired ____ skills

• ___% have normal or better intelligence

• not interested in interacting with others

• lack of ____

interest, social, 50, imagination

infants who develop autism show traits at 9 months of age:

• abnormal ____

• ____ contact

• response to their ____

• back and fourth ____

imitation, eye, name, vocalizations

brain differences in autism

• reduced communication amount in ____ areas

• ____ than normal ____

• abnormal shape of ____ and ____ correlates with motor, social, and communication

cerebral, larger, amygdala, caudate, putamen