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Copyright 2008 Pearson Education, Inc., publishing as Benjamin
Cummings.Central Nervous SystemCNS: brain and spinal cordNecessary
for the maintenance of homeostasisContains 1011 neuronsContains
1014 synapsesResponsible for everything we perceive, do, feel, and
think
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Cummings.
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Copyright 2008 Pearson Education, Inc., publishing as Benjamin
Cummings.Glial Cells90% of CNS composed of gliaFive types of glial
cellsAstrocytenumerous functionsEpendymal cellsline
cavitiesMicrogliaphagocytesOligodendrocytesform myelinSchwann cells
(located in PNS)form myelin
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Cummings.
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Copyright 2008 Pearson Education, Inc., publishing as Benjamin
Cummings.Glial CellsFigure 9.1
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Cummings.
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Copyright 2008 Pearson Education, Inc., publishing as Benjamin
Cummings.AstrocytesDevelopment of neural connectionsPossibly
modulate synaptic activityRemove neurotransmitter from synaptic
cleftCommunicate to neurons through chemical messengersMaintain
normal electrolyte composition of ISF in CNSProtect neurons against
toxic substances and oxidative stress
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Cummings.
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Copyright 2008 Pearson Education, Inc., publishing as Benjamin
Cummings.MicrogliaProtect CNS from foreign matter through
phagocytosisBacteriaDead or injured cellsProtect CNS from oxidative
stress
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Cummings.
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Copyright 2008 Pearson Education, Inc., publishing as Benjamin
Cummings.CNS: Physical SupportFigure 9.2a
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Cummings.
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Copyright 2008 Pearson Education, Inc., publishing as Benjamin
Cummings.CNS: Physical SupportFigure 9.2b
Copyright 2008 Pearson Education, Inc., publishing as Benjamin
Cummings.
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Copyright 2008 Pearson Education, Inc., publishing as Benjamin
Cummings.Cerebrospinal Fluid (CSF)Extracellular fluid of the
CNSSecreted by ependymal cells of the choroid plexusCirculates to
subarachnoid space and ventriclesReabsorbed by arachnoid
villiFunctionsCushions brain Maintains stable interstitial fluid
environment
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Cummings.
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Copyright 2008 Pearson Education, Inc., publishing as Benjamin
Cummings.Figure 9.3cCerebral Spinal Fluid
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Cummings.
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Copyright 2008 Pearson Education, Inc., publishing as Benjamin
Cummings.CSF ProductionTotal volume of CSF = 125150 mLChoroid
plexus produces 400500 mL/dayRecycled three times a day
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Cummings.
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Copyright 2008 Pearson Education, Inc., publishing as Benjamin
Cummings.Blood Supply to the CNSCNS comprises 2% of body weight (34
pounds)Receives 15% of blood supplyHigh metabolic rateBrain uses
20% of oxygen consumed by body at restBrain uses 50% of glucose
consumed by body at restDepends on blood flow for energy
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Cummings.
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Copyright 2008 Pearson Education, Inc., publishing as Benjamin
Cummings.High Demand for BloodDepends on aerobic glycolysisRequires
glucose and oxygenNo glycogen storesFatty acids not used for energy
Ketones used during extreme conditions
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Cummings.
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Copyright 2008 Pearson Education, Inc., publishing as Benjamin
Cummings.StrokeCaused by decreased blood supplyOcclusion of
cerebral blood vesselHemorrhage from cerebral blood vessel
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Cummings.
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Copyright 2008 Pearson Education, Inc., publishing as Benjamin
Cummings.Blood-Brain BarrierCapillariesSites of exchange between
blood and interstitial fluidBlood-brain barrierSpecial anatomy of
CNS capillaries which limit exchange
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Cummings.
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Copyright 2008 Pearson Education, Inc., publishing as Benjamin
Cummings.Blood-Brain BarrierFigure 9.4b
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Cummings.
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Copyright 2008 Pearson Education, Inc., publishing as Benjamin
Cummings.CNS: Gray and White MatterFigure 9.5a
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Cummings.
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Copyright 2008 Pearson Education, Inc., publishing as Benjamin
Cummings.White Matter in BrainProjection fibersCerebral cortex with
lower levels of brain or spinal cordAssociation fibers Connect two
areas of cerebral cortex on same side of brainCommissural fibers
Connect same cortical regions on two sides of brainCorpus callosum
Primary location of commissural fibers
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Cummings.
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Copyright 2008 Pearson Education, Inc., publishing as Benjamin
Cummings.CNS: Gray and White MatterFigure 9.5bc
Copyright 2008 Pearson Education, Inc., publishing as Benjamin
Cummings.
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Copyright 2008 Pearson Education, Inc., publishing as Benjamin
Cummings.II. Spinal CordCylinder of nerve tissueContinuous with
brainSurrounded by vertebral columnOrigin of spinal nerves (31
pairs)
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Cummings.
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Copyright 2008 Pearson Education, Inc., publishing as Benjamin
Cummings.Spinal CordFigure 9.6
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Cummings.
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Copyright 2008 Pearson Education, Inc., publishing as Benjamin
Cummings.DermatomeSensory region of skinEach served by spinal
nerve
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Copyright 2008 Pearson Education, Inc., publishing as Benjamin
Cummings.DermatomeFigure 9.7
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Copyright 2008 Pearson Education, Inc., publishing as Benjamin
Cummings.Spinal Cord and Spinal NervesGray matter: functional
halvesDorsal: sensory functionsVentral: motor functionsSpinal
nerves are mixedWhite matter forms tractsAscendingDescending
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Copyright 2008 Pearson Education, Inc., publishing as Benjamin
Cummings.Spinal Cord: Cross SectionFigure 9.8
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Cummings.
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Copyright 2008 Pearson Education, Inc., publishing as Benjamin
Cummings.Spinal Cord: TractsFigure 9.9
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Cummings.
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Copyright 2008 Pearson Education, Inc., publishing as Benjamin
Cummings.Spinal Cord: Ascending TractsFigure 9.10a
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Cummings.
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Copyright 2008 Pearson Education, Inc., publishing as Benjamin
Cummings.Spinal Cord: Descending TractsFigure 9.10b
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Cummings.
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Copyright 2008 Pearson Education, Inc., publishing as Benjamin
Cummings.BrainFigure 9.11ab
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Copyright 2008 Pearson Education, Inc., publishing as Benjamin
Cummings.Figure 9.11cMidbrainSpinal cordPonsMedulla
oblongataForebrainCerebrumThalamusHypothalamusPituitary
glandBrainstemDiencephalonCerebellumCorpus callosum(c)Midsagittal
sectionBrain: Midsagittal View
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Cummings.
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Copyright 2008 Pearson Education, Inc., publishing as Benjamin
Cummings.Premotor cortex(coordinatesvoluntarymovements)Primary
somatosensorycortex (somesthetic sensationsand
proprioception)Sensory associationareas (integration ofsensory
information)Primary motor cortex(voluntary movement)Central
sulcusPrefrontalassociationareas (idea andplan for
voluntarymovement, thoughts,personality)Brocas area(speech
formation)Limbic associationcortex (emotions,learning, and
memory)Olfactory cortex(smell)Visual associationareas (higher
visionprocessing)Wernickes
area(languagecomprehension)AuditoryassociationareasPrimary
auditorycortex (hearing)Primary visual cortex(vision)Functional
Areas of CerebrumFigure 9.14Functional Areas of Cerebrum
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Copyright 2008 Pearson Education, Inc., publishing as Benjamin
Cummings.Topographical Organization: MotorFigure 9.15b
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Copyright 2008 Pearson Education, Inc., publishing as Benjamin
Cummings.Topographical Organization: SensoryFigure 9.15a
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Copyright 2008 Pearson Education, Inc., publishing as Benjamin
Cummings.The Limbic SystemFigure 9.17
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Copyright 2008 Pearson Education, Inc., publishing as Benjamin
Cummings.Functions of Limbic SystemLearningEmotionsBehavior
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Copyright 2008 Pearson Education, Inc., publishing as Benjamin
Cummings.ReflexesAutomatic patterned response to a stimulus
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Copyright 2008 Pearson Education, Inc., publishing as Benjamin
Cummings.Classes of ReflexesTable 9.3
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Copyright 2008 Pearson Education, Inc., publishing as Benjamin
Cummings.Reflex ArcFigure 9.18
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Copyright 2008 Pearson Education, Inc., publishing as Benjamin
Cummings.Stretch ReflexFigure 9.19
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Copyright 2008 Pearson Education, Inc., publishing as Benjamin
Cummings.Withdrawal and Crossed-Extensor ReflexesFigure 9.20
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Cummings.
