PART VINERVOUSSYSTEMChapter1 General Description1.Composition of Nervous SystemII.TerminologyII.Reflexand ReflexArcsChapter 2Central Nervous SystemIN.Blood SupplyoftheBrainstemSection1 Spinal CordV.CerebellumI.Extermal Features of Spinal CordV.DiencephalonI.Intermal Structure of the Spinal CordSection3TelencephalonII.Functions of Spinal CordI.External FeaturesSection2 Brain StemII.Limbic Lobe and Limbic SystemI.ExternalAppearanceIII.Cerebral CortexIIIntemal StructureIN.Internal StructureII.ReticularFormationChapter3Neural PathwaysIV.Auditory (Acoustic)PathwaySection1 Sensory (Ascending)PathwaysV.Equilibratory PathwayI.Superficial SensoryPathwaySection2Motor(descending)PathwaysII. Deep Sensory (or the Proprioceptive) Path-I.Pyramidal SystemwaysII.Extrapyramidal SystemII.Visual Pathway and PupillaryLight ReflexChapter 4Meninges, Blood Vessels of Brain, Spinal Cord, and the Cerebrospinal FluidII. Blood Vessels of Spinal CordSectionI MeningesofBrainand SpinalCordSection3Circulationof theCerebrospinalFluidI.Dura MaterSection4 BrainBarriersII.ArachnoidI.Blood-Brain BarrierII.Pia MaterI.Blood-Cerebrospinal Fluid BarrierSection2BloodVesselsofBrainandSpinalCordII.Cerebrospinal Fluid Brain BarrierI.Arteries of BrainII. Veins of Brain· 283 ·扫描全能王创建
·284.PARTV NERVOUSSYSTEMChapter5 Peripheral Nervous SystemI.Sensory Cranial NervesSection1 Spinal NervesI.Motor Cranial NervesI.TheAnteriorBranchesof ThoracicNervesII. Mixed Cranial NervesII.The Cervical PlexusSection3Autonomic Nervous SystemII.Brachial PlexusI.Visceral Efferent (Motor) NervesIV.LumbarPlexusII.Visceral Afferent (Sensory)NervesV.Sacral PlexusIII.CentresofVisceral NervesSection2 Cranial NervesIntroductionThe nervous system controls and coordinates most of the activities of the body, matching them to thecontinuously changing circumstances of the world around.In order to carry out thesefunctions,thenervoussystemmonitors events intheexternal environmentand within the body,coordinates all this informationSkullandmatchesit againstpastexperience,and instructsBrainother systems,such as somatic muscle,to produceanappropriate response. This response will in turn alterCranial nethe information coming from thebody and the externalenvironment.Nervous system can be divided into peripheral nervous system and central nervous system (Fig.V-1).Cranial nerveXSpinal cord1.Peripheral nervous system (PNS)Spinal nervesSpinal processThis system is formed by the cranial and spinalnerves and the peripheral part of the visceral nervoussystem. It collects the information from specializedsensory receptors throughout the body and transmitsVertebral bodythis information to the central nervous system. Theperipheral nervous system also carries commands fromthe central nervous system to effectors.2. Central nervous system (CNS)The central nervous system comprises the brainand spinal cord which are wrapped in protective cover-ingsthmrlis inthecranialcaity,andthlattrlocated in the vertebral canal.Fig.VI-1 Structure of the CNS and PNS扫描全能王创建
Chapter 1 General DescriptionI.Composition of NervousSystemDendriteThe nervous system is basically formed by theSpineneroustisuewhichconsissofwoprincipalcellularCell bodyof presynaptic neuronconstituents,the nerve cells or neurons, and neurogli-Dendriteal cells or glia. The neuron is the structural and func-tional unit of the nervous system and the glia provide-AxonhillockAxonstructural and metabolic support for neurons.Myelin sheath1.NeuronsSynaptic cleftconteminal(1) Structure of neurons (Fig. VI-1-1)synapticneuroAlthough neurons are different in shapes and siz-es, each has four morphologically specialized regions(Fig.VI-1-1) : cell body, dendrites, axon, and axonFig.VI-1-1A Schematie nerve cell is shown,illusterminals. A neuron can be defined, functionally, as 3trating thedendrites, cell body, axon, and axonzones: Receptor zone(cell body and dendrites)terminalsat where the afferent or incoming impulses arrive.2)DendritesMost neurons usuallyhave many② Conducting zone(axon) specialized for conduc-dendrites.The cytoplasm of dendrites resembles thattion of the nervous impulse.Effector zone(axonof the perikaryon, with granular endoplasmic retic-terminals) where electrical or chemical signals areulum (Nissl bodies)in theirproximal trunks and attransmitted across specialized junction (synapse).points of branching. The surface area of the dendrites1) Cell body The cell body, or perikaryon isis usually far larger than that ofthe cell body.In somethe metabolic andgenetic center ofaneuron (Fig.Vneurons, the smaller branches bear large numbers of1-1,2)It contains a nucleus with a prominent nu-minutemushroom shaped projections,called dendrit-clelusfrapproriastainingroceduresoic spines, which receive the nerve impulses comingcan demonstrate within the cytoplasm of nerve cellsfrom the otherneurons (Fig.VI-1-1).neurofibrils, chromophil substance (Nissl bodies),3) Axons and axon terminalsA neuron has aGogiapparatumitcndriaattimsacntrasingle axon, which is a cylindrical tube of cytoplasmbody,andvarious incluions such as pigment,andlcovered by a membrane, the axolemma.The axonidsNeurbrilsareunquely characterisiconereconducts electrical signals from the cell body to thecellwhsamaxon terminals. In large neurons, the initial segmentobsersuellsMosseoniof axon form a coneshaped portion, the axon hillock,unsarevisualizedsmultanuslywiththeectrowhich is free of Nissl bodies.Distally each axonmicroscope.. 285 .扫描全能王创建
·286·PARTVI NERVOUSSYSTEMbreaks up into simple or extensive terminal arboriza-(2) Classification of neurons (Fig. Vtions which end as synaptic terminals (alsoknown as1-1, 4)terminal button) in contact with other cells (Fig. VI-1-1,3)to form the synapses.Collateral branches may1Based onumber of processesarisingfrom celbegiven off from the axon.byrnsaeduparruoaamioamuprons are different greatly in shape.2) Based on length of axons, neurons arealsoclasified into threetypes (Fig.V-4) GolgtypeIneurons havelong axons.The longestaxonsin the central nervous system (CNS) ofhumans ex-tend from the cerebral cortextothe caudaltipofthespinal cord adistanceof570cm; GolgitypelIneurons have short axons. The shortest axons terminateonly a few micra from the perikaryon; Amacrine neu-rons, an unusual neuron type, lack axons.Primary sensoryneuronofspinalganglion(has no trueGPrincipalneuronMotorneurondendrites)of sympatheticofspinal cordganglionFig.VI-1-2 The diaphragm of neuron cell body1 nuclear membrane;2pores in nuclear membrane;3 interior ofnucleus; 4 nucleolus; 5Golgi apparatus; 6 smooth endoplasmicreticulum; 7granular endoplasmic reticulum; 8mitochondrion; 9microtubule; 10 microfilament; 11 axon hillock; 12 initial segmentofaxon;13 soma (perikaryon)ofcell;14dendrite;15 pinocytoticvesicle; 16 lipofuscin granuleAxonDendriteAxontermialsAmacrine cell of retina(hasnoaxon)CollateralbralSA.bipolarneuronTractcell of spinalgraymatterDendriteGolgi type 1l intemeuronAxonFig. VI-1-4 Variety of neuron shapes3) Based on theirfunction, all neurons fall intoB.unipolarneuronthree types (Fig. VI-1-5). Sensory neurons receivestimuli andtransmit afferent impulsetothe CNS.Association neurons (also called interneurons) lies in theDenCollateral branchcentral nervous system forming the complex nervouscircuits.Motoneurons deliverefferent impulses fromAxonthecentralnervoussystemtotheperipheralnervousC.multipolarneuronsystem (PNS) to activate effectors.Fig.VI-1-3Morphological classification of neurons扫描全能王创建
General Description ·287.Chapter1NervecellReceptorsurfaceSynapseespecially reactivetoonekindofenvironmental changeA.a sensory neuronSynapseNervecellNervecellsB.aassociation neuronsMusclefibreMotor end plateC.amotor neuronFig.VI-1-5 Functional classification of neurons4)Based on classification of neurotransmittersstance-Neurotransmitters.Electrical synapses arechemistry,neurons may also group as monoaminer-only present in invertebrates and fishes.The chemicalgic,cholinergic,aminoacidergic,peptidergic,and sosynapses can be classified, according to the neuronalon.regions that participate informing the synapse,intoaxodendriticsynapses andaxosomatic synapses (mostSynapses and Neurotransmicommon)or,less often,dendrodendritic synapssandaxoaxonal synapses.ttersTypical chemical synapses may be divided into 3parts (Fig.VI-1-6):the presynaptic part with theCommunication between neurons usually occursdense thickening presynaptic membrane;②the post-at specialized junctions called synapses, whereexcisynapticpartwiththepostsynapticmembranethetation is transmitted from one nerve cell to another.synaptic clef,a narrowgap about 20nmwide whichWe callthe neuron sending information the presyn-separates thepresynaptic and postsynapticmembrane.aptic neuron and the other is called the postsynapticThe presynaptic part contains numerous vesicles, inneuron which receives the information.which the chemical substances neurotransmitter ispresent.(1)Synapses(2)NeurotransmittersSynapses can be formed between almost any re-gionsofthwoparticipatingnuronThmostcomNeurotransmitters are small molecular weightmontypefsyapsesoccursbetweenaterminalofancompounds;amongtheseareacetylcholine andmono-axonal branchofaneuron andadendriteorasomaofaminergic compounds such as norepinephrine andanother (Fig )hesyaes may bdivdserotonin. Amino acids (e.g.glutamate, glycine, andinowokindthhemicalsynapsesandelectrical-aminobutyric acid,or GABA)and larger molecules,synapses.The chemical synapses isthe most comsuch as peptides (e. g. enkephalin and substance P)montyeinthemammalianneroussytemwhichalso function as neurotransmitters.When an impulsetranmitsthenerousimpusebythechemicalsub扫描全能王创建