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1、The Nervous System山东大学医学院山东大学医学院 解剖教研室解剖教研室李振华李振华DivisionsnCentral nervous system(CNS)nPeripheral nervous system(PNS)Central nervous system(CNS)nBrain 脑脑qTelencephalon 端脑端脑qDiencephalon 间脑间脑qCerebellum 小脑小脑qBrain stem 脑干脑干 nMidbrain 中脑中脑nPons 脑桥脑桥nMedulla oblongata 延髓延髓nSpinal cord 脊髓脊髓Peripheral ne
2、rvous system(PNS)nCranial n.(12 pairs)脑神经脑神经nSpinal n.(31 pairs)脊神经脊神经nVisceral n.内脏神经内脏神经qVisceral sensory n.qVisceral motor nnSympathetic part 交感神经交感神经n Parasympathetic part 副交感神经副交感神经nNeurons 神经元神经元 qCell body 胞体胞体qAxon 轴突轴突qDendrites 树突树突 n Neuroglia glial cell胶质细胞胶质细胞 Structural classificationn
3、Bipolar neuron 双极神经元双极神经元 has an axon and a dendritenPseudounipolar neuron 假假单极神经元单极神经元 has a central branch and a peripheral branchnMultipolar neuron多极神经元多极神经元has an axon and two or more dendritesFunctional classificationnSensory(efferent)neuron 感觉神经元感觉神经元nMotor(afferent)neuron 运动神经元运动神经元nAssociati
4、on neuron 联络神经元联络神经元nReflex:a reaction of the organism by the nervous system in response to a stimulusnReflex arc:has 5 basic components Receptor Sensory neurons CNS Moter neurons Effector Reflex and reflex arcBasic terminology in nervous system In the CNSnGray matter 灰质灰质:collection of nerve cell b
5、odies and their dendrites,gray color during fresh conditionnCortex皮质皮质:the outermost layer of gray matter in cerebrum and cerebellumnWhite matter白质白质:collection of nerve fibers,white color during fresh conditionnMedulla髓质髓质:a central core of white matter beneath cortex of cerebrum and cerebellumnNuc
6、leus神经核神经核:a collection(group)of cell bodies which have the same shape and functionnFasciculus 纤维束纤维束(tract):a bundle of nerve fibers which have the same origin,termination,pathway and functionnReticular formation 网状结构网状结构:an admixture of cross-crossing fibers with larger or smaller groups of nerve
7、cells occupying the meshesIn the PNSnGanglion 神经节神经节:a collection of neuronal cell bodies outside the CNSnNerve 神经神经:a bundle of nerve fibers held together by connective tissue sheathThe Spinal Cord 脊髓脊髓PositionnLies in vertebral canalnContinuous above with medulla oblongata at level of foramen magn
8、um nEnds below at lower border of L1 in adult;at birth at level of L3External featuresnA long cylindrical structure and slightly flattened anteroposteriorly,nConus medullaris（脊髓圆锥）（脊髓圆锥）nFilum terminale（终丝）（终丝）nCauda equina（马尾）（马尾）nTwo enlargements Cervical enlargement（颈膨大）颈膨大）:corresponds to the C4
9、 to the T1 segments Lumbosacral enlargement （腰骶膨大）（腰骶膨大）:corresponds to the L2 to the S3 segmentsFissure and sulcinAnterior median fissure 前正中裂前正中裂nPosterior median sulcus 后正中沟后正中沟nAnterolateral sulcus 前外侧沟前外侧沟anterior(motor)roots emerge serially nPosterolateral sulcus 后外侧沟后外侧沟posterior(sensory)root
10、s enter spinal cord,each bear a spinal ganglion which constitutes the first cell-station of the sensory nervesRelationship of segments of spinal cord to vertebrae nA portion of the cord that gives rise to a pair of spinal nerve constitutes a segment.nThere are 31 segments 8 cervical 12 thoracic 5 lu
11、mbar 5 sacral 1 coccygealRelationship of segments of spinal cord to vertebraeSpinal segmentsVertebral levels(spines)Upper cervical region(C1C4)=C1 C4Lower cervical and upper thoracic region(C5T4)1=C4 T3Middle thoracic region(T5T8)2=T3 T6Lower thoracic region(T9T12)3=T6 T9Lumber segments=T10 T12Sacra
12、l and coccygeal segments=L1 Internal structures nCentral canal 中央管中央管nGray matterqAnterior horn(column)前角（柱）前角（柱）qPosterior horn(column)后角（柱）后角（柱）qIntermediate zone 中间带中间带nLateral horn(column)侧角（柱）侧角（柱）qAnterior gray commissures 灰质前连合灰质前连合qPosterior gray commissures 灰质后连合灰质后连合nWhite matterqAnterior
13、funiculus 前索前索qlateral funiculus 外侧索外侧索qPosterior funiculus 后索后索qAnterior white commisure 白质前连合白质前连合 Posterior horn(column):nMarginal layer（缘层）nSubstantia gelatinosa （胶状质）nNucleus proprius （后角固有核）nNucleus thoracicus（胸核）in segments C8L3 Intermediate zonenIntermediaolateral nucleus （中间外侧核）(lateral hor
14、n or column):lies in segments T1L3,containing sympathetic preganglionic neuronsnSacral parasympathetic nucleus（骶副交感核）:lies in segments S2S4,containing parasympathetic preganglionic neuronsnIntermediomedial nucleus （中间内侧核）:for sensation of viscera Anterior horn(column):contain motor neurons nThree ki
15、nds of neuron q-motor neuron:larger multipolar neuron,innervates extrafusal fibers of skeletal m.,producing contraction of m.q-motor neuron:smaller neuron,innervates intrafusal fibers regulating muscular tonusqRenshaws cell:negative feedback mechanismnTwo groups of nucleiqMedial nuclear group:presen
16、t in most segments of spinal cord,innervating axial musclesqLateral nuclear group:present only in cervical and lumbosacral enlargements,innervating limb muscles Rexeds lamina 板层板层nposterior horn is formed by lamina to；nIntermediate zone corresponding to lamina；nAnterior horn is composed laminae and；
17、nlamina is the gray matter surrounding the central canal.Important Subdivision of Spinal Cord Gray MatterRegion LaminaNucleusPosterior hornMarginal layerSubstantia gelatinosa,Nucleus propriusIntermediate zoneNucleus thoracicus(C8L3)Intermediolateral nucleus(T1L3)Sacral parasympathetic nucleus(S2S4)I
18、ntermediomedial nucleus Anterior hornMotor neuron)White matter White matter contains three kinds of fibers:ascending,descending,and fasciculus propriusAscending tractsFasciculus gracilis（薄束）（薄束）Fasciculus cuneatus（楔束）（楔束）Posterior spinocerebellar tract（脊髓小脑后束）（脊髓小脑后束）Anterior spinocerebellar tract（脊
19、髓小脑前束）（脊髓小脑前束）Spinothalamic tract（脊髓丘脑束）（脊髓丘脑束）Ascending tractsTract Site of originFuniculus TerminationFunction Fasciculus gracilisSpinal ganglia below segment T5Posterior Gracile nucleusConvey proprioceptive and fine touch sensation of trunk and limbsFasciculus cuneatusSpinal ganglia above segment
20、 T4Cuneate nucleusPosterior spinocerebellarHomolateral nucleus thoracicusLateral Cerebellum Unconscious proprioception from lower limb and lower portion of trunkAnterior spinocerebellarContralateral Laminae Spinothalamic Laminae,Lateral and anteriorDorsal thalamusPain,temperature and simple touch se
21、nsation of trunk and limbs Descending tracts Lateral corticospinal tract（皮质脊髓侧束）（皮质脊髓侧束）Anterior corticospinal tract（皮质脊髓前束）（皮质脊髓前束）Rubrospinal tract（红核脊髓束）（红核脊髓束）Vestibulospinal tract（前庭脊髓束）（前庭脊髓束）Reticulospinal tract（网状脊髓束）（网状脊髓束）Medial longitudinal fasciculus（内侧纵束）（内侧纵束）Tectospinal tract（顶盖脊髓束）（顶
22、盖脊髓束）Fasciculus proprius（固有束）（固有束）Descending tractsTract Site of originFuniculus TerminationFunction Lateral corticospinal Cerebral cortexLateral Laminae anterior hornVoluntary movementAnterior corticospinalCerebral cortexAnterior Rubrospinal Red nucleusLateral Laminae Excitatory of flexorsVestibulo
23、spinal Homolateral vestibular nucleiAnteriorLaminae Excitatory of extensorsReticulospinal Reticular formationAnterior and lateral Laminae Voluntary movementMedial longitudinal fasciculusVestibular nucleiAnteriorLaminae Coordinate neck with eye movementTectospinal Superior colliculusAnteriorLaminae Fasciculus propriusSpinal cordAnterior,lateral and posteriorSpinal cordIntrinsic reflex mechanism of spinal cordMain functions of spinal cordn Conduction of excitationsn Reflex activity