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1、Divisions,Central nervous system (CNS) Peripheral nervous system (PNS),Central nervous system (CNS) Brain 脑 Telencephalon 端脑 Diencephalon 间脑 Cerebellum 小脑 Brain stem 脑干 Midbrain 中脑 Pons 脑桥 Medulla oblongata 延髓 Spinal cord 脊髓,Peripheral nervous system (PNS) Cranial n. (12 pairs) 脑神经 Spinal n. (31 pai
2、rs) 脊神经 Visceral n. 内脏神经 Visceral sensory n. Visceral motor n Sympathetic part 交感神经 Parasympathetic part 副交感神经,Neurons 神经元 Cell body 胞体 Axon 轴突 Dendrites 树突 Neuroglia glial cell胶质细胞,Structural classification Bipolar neuron 双极神经元 has an axon and a dendrite Pseudounipolar neuron 假单极神经元 has a central b
3、ranch and a peripheral branch Multipolar neuron多极神经元has an axon and two or more dendrites Functional classification Sensory (efferent) neuron 感觉神经元 Motor (afferent) neuron 运动神经元 Association neuron 联络神经元,Reflex: a reaction of the organism by the nervous system in response to a stimulus Reflex arc: ha
4、s 5 basic components Receptor Sensory neurons CNS Moter neurons Effector,Reflex and reflex arc,Basic terminology in nervous system,In the CNS Gray matter 灰质: collection of nerve cell bodies and their dendrites, gray color during fresh condition Cortex皮质: the outermost layer of gray matter in cerebru
5、m and cerebellum White matter白质: collection of nerve fibers, white color during fresh condition Medulla髓质: a central core of white matter beneath cortex of cerebrum and cerebellum Nucleus神经核: a collection ( group ) of cell bodies which have the same shape and function,Fasciculus 纤维束( tract ): a bund
6、le of nerve fibers which have the same origin, termination, pathway and function Reticular formation 网状结构: an admixture of cross-crossing fibers with larger or smaller groups of nerve cells occupying the meshes,In the PNS Ganglion 神经节: a collection of neuronal cell bodies outside the CNS Nerve 神经: a
7、 bundle of nerve fibers held together by connective tissue sheath,The Spinal Cord 脊髓,Position Lies in vertebral canal Continuous above with medulla oblongata at level of foramen magnum Ends below at lower border of L1 in adult; at birth at level of L3,External features,A long cylindrical structure a
8、nd slightly flattened anteroposteriorly, Conus medullaris （脊髓圆锥） Filum terminale （终丝） Cauda equina （马尾） Two enlargements Cervical enlargement （颈膨大）: corresponds to the C4 to the T1 segments Lumbosacral enlargement （腰骶膨大）: corresponds to the L2 to the S3 segments,Fissure and sulci Anterior median fis
9、sure 前正中裂 Posterior median sulcus 后正中沟 Anterolateral sulcus 前外侧沟anterior (motor) roots emerge serially Posterolateral sulcus 后外侧沟posterior (sensory) roots enter spinal cord, each bear a spinal ganglion which constitutes the first cell-station of the sensory nerves,Relationship of segments of spinal
10、cord to vertebrae,A portion of the cord that gives rise to a pair of spinal nerve constitutes a segment. There are 31 segments 8 cervical 12 thoracic 5 lumbar 5 sacral 1 coccygeal,Relationship of segments of spinal cord to vertebrae,Internal structures,Central canal 中央管 Gray matter Anterior horn (co
11、lumn) 前角（柱） Posterior horn (column)后角（柱） Intermediate zone 中间带 Lateral horn (column) 侧角（柱） Anterior gray commissures 灰质前连合 Posterior gray commissures 灰质后连合 White matter Anterior funiculus 前索 lateral funiculus 外侧索 Posterior funiculus 后索 Anterior white commisure 白质前连合,Posterior horn (column): Marginal
12、 layer （缘层） Substantia gelatinosa （胶状质） Nucleus proprius （后角固有核） Nucleus thoracicus（胸核） in segments C8L3,Intermediate zone Intermediaolateral nucleus （中间外侧核）(lateral horn or column): lies in segments T1L3, containing sympathetic preganglionic neurons Sacral parasympathetic nucleus（骶副交感核）: lies in se
13、gments S2S4, containing parasympathetic preganglionic neurons Intermediomedial nucleus （中间内侧核） : for sensation of viscera,Anterior horn (column): contain motor neurons Three kinds of neuron -motor neuron: larger multipolar neuron, innervates extrafusal fibers of skeletal m., producing contraction of
14、 m. -motor neuron: smaller neuron, innervates intrafusal fibers regulating muscular tonus Renshaws cell: negative feedback mechanism Two groups of nuclei Medial nuclear group: present in most segments of spinal cord, innervating axial muscles Lateral nuclear group: present only in cervical and lumbo
15、sacral enlargements, innervating limb muscles,Rexeds lamina 板层,posterior horn is formed by lamina to ； Intermediate zone corresponding to lamina ； Anterior horn is composed laminae and ； lamina is the gray matter surrounding the central canal.,Important Subdivision of Spinal Cord Gray Matter,) White
16、 matter,White matter contains three kinds of fibers: ascending, descending, and fasciculus proprius,Ascending tracts,Fasciculus gracilis（薄束）,Fasciculus cuneatus （楔束）,Posterior spinocerebellar tract （脊髓小脑后束）,Anterior spinocerebellar tract （脊髓小脑前束）,Spinothalamic tract （脊髓丘脑束）,Ascending tracts,Descendi
17、ng tracts,Lateral corticospinal tract （皮质脊髓侧束）,Anterior corticospinal tract （皮质脊髓前束）,Rubrospinal tract （红核脊髓束）,Vestibulospinal tract （前庭脊髓束）,Reticulospinal tract （网状脊髓束）,Medial longitudinal fasciculus （内侧纵束）,Tectospinal tract （顶盖脊髓束）,Fasciculus proprius （固有束）,Descending tracts,Main functions of spinal cord,Conduction of excitations Reflex activity,