Chapter 9Emergent Properties of Neural NetworksPowerPoint PresentationCNS: Gray and White MatterCNS: Bone and Connective TissueCentral Nervous SystemCerebrospinal FluidSlide 8Blood-Brain BarrierSlide 10Spinal CordSpinal Cord: Gray MatterSpinal Cord: White MatterSlide 14Slide 15CNS: Neural Tissue – Metabolic NeedsFigure 9.8 ANATOMY SUMMARY – Central Nervous SystemThe Brain: The Brain StemBrain StemThe Cranial NervesBrainFigure 9.9Slide 23Slide 24Slide 25Brain Function: Cerebral CortexCerebral CortexBrain Function: Sensory InformationSlide 29Brain Function: Motor SystemChapter 9•Anatomy of the central nervous system•The spinal cord•The brain•Brain function© 2013 Pearson Education, Inc.Emergent Properties of Neural Networks•Affective behaviors are related to feeling and emotion•Cognitive behaviors link to thinking© 2013 Pearson Education, Inc.ANATOMY SUMMARYCNS: Gray and White Matter •Gray matter–Unmyelinated nerve cell bodies–Clusters of cell bodies in the CNS are nuclei–Dendrites–Axon terminals•White matter–Myelinated axons–Axon bundles connecting CNS regions are tracts–Contains very few cell bodies© 2013 Pearson Education, Inc.CNS: Bone and Connective Tissue•Brain is encased in bony skull, or cranium•Spinal cord runs through vertebral column•Meninges lie between bone and tissues to stabilize neural tissue and protect from bruising–Dura mater–Arachnoid membrane–Subarachnoid space contains cerebrospinal fluid secreted by choroid plexus- dumps sodium out and water follows–Pia mater© 2013 Pearson Education, Inc.Central Nervous SystemPosterior View of the Central Nervous System Sectional View of the Meninges of the Brain, showinghow they cushion and protect delicate neural tissueCraniumCerebralhemispheresCerebellumCervical spinalnervesCraniumDuramaterVenous sinusArachnoidmembranePia materBrainSubduralspaceSubarachnoidspaceMoving from the cranium in,name the meninges that formthe boundaries of the venoussinus and the subdural andsubarachnoid spaces.FIGURE QUESTIONCerebrospinal FluidThe Ventricles of the BrainLateral ventriclesThird ventricleFourth ventricleCerebellumCentral canalSpinal cordFrontal viewLateral viewThe lateral ventricles consist ofthe first and second ventricles.The third and fourth ventriclesextend through the brain stemand connect to the centralcanal that runs through thespinal cord. Compare thefrontal view to the crosssection in Fig. 9.10a.Cerebrospinal FluidANATOMY SUMMARYThe Choroid PlexusThe choroid plexustransports ions andnutrients from the bloodinto the cerebrospinal fluid.CapillaryEpendymalcellsIons, vitamins,nutrientsWaterCerebrospinalfluid in third ventricleFIGURE QUESTIONSPhysicians may extract a sample ofcerebrospinal fluid when they suspectan infection in the brain. Where is theleast risky and least difficult place forthem to insert a needle through themeninges? (See Fig. 9.4b.)1.2.The aqueduct of Sylvius is the narrowpassageway between the third and fourthventricles. What happens to CSF flowif the aqueduct becomes blocked byinfection or tumor, a condition known asaqueductal stenosis {stenos, narrow}?On a three-dimensional imaging studyof the brain, how would you distinguishaqueductal stenosis from a blockage ofCSF flow in the subarachnoid space nearthe frontal lobe?ANATOMY SUMMARYCerebrospinal Fluid SecretionCerebrospinal fluid is secreted into the ventriclesand flows throughout the subarachnoid space,where it cushions the central nervous system.Choroid plexusof third ventriclePia materArachnoidmembraneArachnoidvilliSinusSpinal cordCentral canalSubarachnoidspaceArachnoidmembraneDura materChoroid plexusof fourth ventricleBlood-Brain BarrierAstrocyteAstrocyte foot processessecrete paracrines thatpromote tightjunction formation.Tight junction preventssolute movementbetween endothelial cells.Astrocyte foot processessecrete paracrines thatpromote tightjunction formation.Tight junction preventssolute movementbetween endothelial cells.Astrocyte footprocessesTightjunctionBasallaminaCapillary lumenBlood-Brain BarrierSpinal CordOne segment of spinal cord, ventral view,showing its pair of nerves.White matterGray matterDorsal root:carries sensory(afferent)informationto CNS.Ventral root: carries motor (efferent)information to musclesand glands.Spinal Cord: Gray MatterGray matter consists of sensory and motor nuclei.Visceral sensory nucleiDorsalrootganglionLateralhornVentralrootVentralhornDorsalhornSomaticsensorynucleiAutonomicefferentnucleiSomaticmotornucleiSpinal Cord: White MatterKEYAscending tractscarry sensoryinformation to the brain.Descending tractscarry commands tomotor neurons.White matter in the spinal cord consists of tracts ofaxons carrying information to and from the brain.To the brainSpinal Cord: White MatterKEYAscending tractscarry sensoryinformation to the brain.Descending tractscarry commands tomotor neurons.White matter in the spinal cord consists of tracts ofaxons carrying information to and from the brain.From the brainSPINAL REFLEXESIn a spinal reflex, sensory information entering the spinal cord isacted on without input from the brain. However, sensoryinformation about the stimulus may be sent to the brain.StimulusSpinalcordIntegratingcenterSensoryinformationInterneuronResponseCommand tomuscles orglandsA spinal reflex initiatesa response without inputfrom the brain.CNS: Neural Tissue – Metabolic Needs•Oxygen–Passes freely across blood–brain barrier–Brain receives 15% of blood pumped by heart•Glucose–Membrane transporters move glucose from plasma into the brain interstitial fluid–Brain responsible for about half of body’s glucose consumption–Progressive hypoglycemia leads to confusion, unconsciousness, and death© 2013 Pearson Education, Inc.Figure 9.8 ANATOMY SUMMARY – Central Nervous SystemThe Brain: The Brain Stem•11 of 12 cranial nerves originate –Cranial nerves can include sensory fibers, efferent fibers, or both (mixed nerves)•Many nuclei are associated with reticular formation•Medulla–Somatosensory and corticospinal tracts –Pyramids•Pons•Midbrain© 2013 Pearson Education, Inc.Lateral View of Brain StemThalamusCut edge ofascendingtracts tocerebrumCranialnervesOptic tractMidbrainPonsCut edgesof tracts leading tocerebellumMedullaoblongataSpinal cordFunctions of the Brain StemMidbrainPons• Eye movement• Relay station between cerebrum and cerebellum• Coordination of breathing• Control of involuntary functions• Arousal• Sleep• Muscle