20. central nervous system

8/8/2019 20. Central Nervous System

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Central Nervous SystemCentral Nervous SystemThe Brain and Spinal CordThe Brain and Spinal Cord


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Tissues of the CNSTissues of the CNS

MeningesMeninges

Three layer of protective tissueThree layer of protective tissue

Around the Brain and Spinal CordAround the Brain and Spinal Cord Physical stability and shock absorptionPhysical stability and shock absorption

The LayersThe Layers

Dura mater (outer)Dura mater (outer)

ArachnoidArachnoid

Pia mater (inner)Pia mater (inner)


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Dura MaterDura Mater

Two sections ofTwo sections of

protective tissueprotective tissue

Outer layer is fused withOuter layer is fused with

periosteum of the skullperiosteum of the skullOuter and innerOuter and inner

separated by dura sinus.separated by dura sinus.

In the spinal cord there isIn the spinal cord there is

no fusingno fusingEpidural spaceEpidural space


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ArachnoidArachnoid

Found between innerFound between inner

Dura mater and Pia materDura mater and Pia mater

Contains lymphatic fluidsContains lymphatic fluids

andand Cerebrospinal FluidCerebrospinal Fluid Shock, absorption,Shock, absorption,

transportationtransportation

Made up of squamousMade up of squamous

cells, collagen and elasticcells, collagen and elastic

fibersfibers


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Pia MaterPia Mater

Pia materPia mater

attached to theattached to the

neural tissueneural tissue

Contains bloodContains blood

vessels (highlyvessels (highly

vascular)vascular)


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Spinal CordSpinal Cord

18 in. Long18 in. Long

Max width of 14mmMax width of 14mm

Tapers as it moves distal from the skullTapers as it moves distal from the skullTwo sites of enlargementsTwo sites of enlargements

Cervical: nerves to shoulder girdles and upperCervical: nerves to shoulder girdles and upper

limbslimbs Lumbar: pelvis and lower limbsLumbar: pelvis and lower limbs

Fibrous tissue connects SC to coccyxFibrous tissue connects SC to coccyx


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StructureStructure

SegmentedSegmented

31 segments paired31 segments paired

with twowith two Dordal RootDordal Root

Ganglia (sensoryGanglia (sensory

neuron cell bodies)neuron cell bodies)

Ventral rootsVentral roots = axons= axons

of motor neuronsof motor neurons


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Central CanalCentral Canal

Filled withFilled with

Cerebrospinal FluidCerebrospinal Fluid

White materWhite mater

Surrounds gray materSurrounds gray mater

Divided into columns:Divided into columns:

Posterior, Lateral,Posterior, Lateral,

AnteriorAnterior

AxonsAxons

Gray materGray mater

Divided into Horns:Divided into Horns:

Posterior, AnteriorPosterior, Anterior

Cell bodiesCell bodies


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Gray MaterGray Mater

Takes on an H shapeTakes on an H shape

Posterior HornsPosterior Horns

Sensory Nuclei (collectionSensory Nuclei (collection

of senory neurons)of senory neurons) Somatic Sensory (mostSomatic Sensory (most

dorsal)dorsal)

Visceral SensoryVisceral Sensory

Anterior HornsAnterior Horns

Motor NucleiMotor Nuclei Somatic Motor (mostSomatic Motor (most

ventral)ventral)

Visceral MotorVisceral Motor


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White MaterWhite Mater

3 Columns3 Columns PosteriorPosterior

AnteriorAnterior

LateralLateral

TractsTracts In the ColumnsIn the Columns

Small: signals betweenSmall: signals betweensegmentssegments

Large: connect spinal cordLarge: connect spinal cordto brainto brain

Ascending: sensory toAscending: sensory tobrainbrain

Decending: MotorDecending: Motorcommandscommands


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BrainBrain

7 Major Regions7 Major Regions

1. Cerebrum1. Cerebrum

2. Diencephalon2. Diencephalon

3. Midbrain3. Midbrain

4. Pons4. Pons

5. Medulla Oblongota5. Medulla Oblongota

6. Cerebellum6. Cerebellum

7. Corpus Collosum7. Corpus Collosum


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Superior SurfaceSuperior Surface

CerebrumCerebrum to Cerebral Hemispheresto Cerebral Hemispheres

Conscious thoughtConscious thought

SensationsSensations Intellectual functionsIntellectual functions

Memory (storage and retrieval)Memory (storage and retrieval)

Complex movementComplex movement


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DiencephalonDiencephalon

ThalamusThalamus

Processing of sensory informationProcessing of sensory information

HypothalamusHypothalamus EmotionEmotion

Autonomic functionAutonomic function

Hormone productionHormone production

PituitaryPituitary

Link between nervous and endocrine systemLink between nervous and endocrine system


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CerebellumCerebellum

Adjust voluntary and involuntary motorAdjust voluntary and involuntary motor

activity based onactivity based on

Sensory informationSensory information Stored memory or previous movementsStored memory or previous movements

20. central nervous system

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