Nervous system Introduction 1 Divisions of nervous system

神经系统 Nervous system

Introduction 1 神经系统的区分 Divisions of nervous system 中枢神经系统 Central nervous system (CNS) 周围神经系统 Peripheral nervous system (PNS)

1) 中枢神经系统 Central nervous system (CNS) 端脑 Telencephalon 脑 Brain 间脑 Diencephalon 小脑 Cerebellum 中脑 Midbrain 脑干 Brain stem 脑桥 Pons 延髓 Medulla oblongata CNS 脊髓 Spinal cord

2）周围神经系统 Peripheral nervous system (PNS) 脑神经 Cranial n. (12 按与中枢的连接部位 pairs) 脊神经 Spinal n. (31 pairs) PNS 躯体神经 躯体感觉神经 Somatic sensory n. Somatic nerve 躯体运动神经 Somatic motor n. 按分布 的 对象 内脏感觉神经 内脏神经 Visceral sensory n. 交感神经 Visceral n. Sympathetic part 内脏运动神经 Visceral motor n. 副交感神经 Parasympathetic part

□ 神经元的分类 ■ 根据突起的数目可将神经元从形态上分为 Structural classification ① 双极神经元 Bipolar neuron ② 假单极神经元 Pseudounipolar neuron ③ 多极神经元 Multipolar neuron 中枢支 central branch 周围支 peripheral branch

■ 按神经元的功能分类 Functional classification ① 传入（感觉）神经元 Afferent (sensory) neuron ② 传出（运动）神经元 Efferent (motor) neuron ③ 联络（中间）神经元 Association neuron (interneuron)

■ 按轴突的长短 Axonal length classification ① 高尔基I型神经元 Neuron of Golgi Type I ② 高尔基II型神经元 Neuron of Golgi Type II ■ 按神经元释放的神经递质 Neurotransmitter classification ① 胆碱能神经元 Cholinergic Neuron ② 胺能神经元 Aminergic Neuron ③ 氨基酸能神经元 Aminoacidnergic Neuron ④ 肽能神经元 Peptidergic Neuron

n Reflex: a reaction of the organism by the nervous system in response to a stimulus n Reflex arc: consist of 5 basic components 感受器 receptor 传入神经 afferent neuron 中枢centre effector 效应器 efferent neuron 传出神经

For example, if one’s fingers are burned by a candle, the hand that receives the painful stimulus is rapidly removed from the flame with a jerking motion.

4常用术语 Basic terminology in nervous system □ 中枢神经系 CNS 1)灰质 Gray matter : -- collection of nerve cell bodies and their dendrites, ■ 皮质 Cortex : -- the outer layer of gray matter in cerebrum and cerebellum ■ 神经核 Nucleus: -- a group of nerve cell bodies which have the same shape and function.

2) 白质 White matter -- collection of nerve fibers, white color during fresh condition ■ 髓质 Medulla : -- a central core of white matter beneath cortex of cerebrum and cerebellum ■ 纤维束 Fasciculus ( tract ) -- a bundle of nerve fibers which have the same origin, termination, and function

3) 网状结构 Reticular formation -- a field of intermingled grey and white matter , and with larger or smaller groups of nerve cells occupying the meshes.

□ 周围神经系 PNS 1) 神经节 Ganglion: -- a collection of neuron cell bodies outside the CNS 2)神经 Nerve: -- a bundle of nerve fibers held together by connective tissue sheath 神经外膜 神经内膜 神经束膜

中枢神经系统 Central nervous system

脊髓 Spinal Cord

脊髓 Spinal Cord 一 脊髓的位置与外形 1 Position: p lies in vertebral canal p continuous with medulla oblongata at level of foramen magnum p ends at the lower border of L 1 p at birth , ends at the level of L 3

2 外形 External features ＊ A long cylindrical structure slightly flattened anteriorly and posteriorly 呈前后稍扁的圆柱形。 后正中沟 1） Fissure and sulci ■ 前正中裂 右后外侧沟 Anterior median fissure ■ 后正中沟 Posterior median sulcus ■ 前外侧沟 右前外侧沟 Anterolateral sulcus ■ 后外侧沟 Posterolateral sulcus 左前外侧沟 前正中裂

2）Two enlargements ◆ 颈膨大 Cervical enlargement ◆ 腰骶膨大 Lumbosacral enlargement 3）脊髓圆锥 conus medullaris 4）终丝 filum terminale 5）马尾 Cauda equina

Lumbar Puncture

3 脊髓节段 Segments of spinal cord -- A portion of the spinal cord that gives attachment to a pair of spinal n. constitutes a segment. 31 segments ◆ Cervical segment 8 ◆ Thoracic segment 12 ◆ Lumbar segment 5 ◆ Sacral segment 5 ◆ coccygeal segment 1

Table 1 Relationship of segments of spinal cord to vertebrae Spinal segments Vertebral levels C 1 ~ C 4 Lie opposite the corresponding C 5~T 4 1 lower in number than corresponding vertebrae T 5 ~ T 8 T 9 ~T 12 vertebrae 2 lower in number than corresponding vertebrae 3 lower in number than corresponding vertebrae Lumber segments T 10~T 12 Sacral and coccygeal segments L 1

二 脊髓的内部结构 Internal structures of the spinal cord 前角 Anterior horn Lateral horn 侧角（T -L ） 1 3 Gray matter 后角 Posterior horn 灰质 中间带： Intermediate zone 灰质前、后连合 Ant. or pos. gray 中央管 Central canal commissure 网状结构 Reticular formation 前索 Anterior funiculus 外侧索 Lateral funiculus 白质 White mater 后索 Posterior Funiculus 白质前连合 Anterior white commissure

脊髓的内部结构的一般模式 1中央管 Central canal 2 灰质 Gray matter 前角 Anterior horn (column) ◆ 后角 Posterior horn (column) ◆ 中间带 Intermediate zone ◆ 3 白质 White matter Anterior funiculus ◆ 外侧索 Lateral funiculus ◆ 后索 Posterior Funiculus ◆ 前索

1 灰质 Gray matter ■ 后角 Posterior horn (column) ◇ 细胞构筑 Cytoarchitecture ① 后角边缘核 Posteromarginal nucleus ② 胶状质 Substantia gelatinosa ③ 后角固有核 Nucleus proprius

■ 中间带 Intermediate zone ◇ 细胞构筑 Cytoarchitecture ① 中间外侧核 Intermediaolateral nucleus -- lies in segments T 1~L 3, containing sympathetic preganglionic neurons --交感神经的低级中枢

★ 骶副交感核 Sacral parasympathetic nucleus -- lies in segments S 2~S 4 -- 副交感神经的低级中枢 ② 中间内侧核 Intermediomedial nucleus -- for sensation of viscera ③胸核（背核） Nucleus thoracicus (dorsalis) -- in segments C 8~L 3

■ 前角 Anterior horn (column) Cytoarchitecture (contain motor neurons) ① α-motor neuron ◇ 细胞构筑 --larger multipolar neuron --支配骨骼肌, 管理随意运动 ② γ-motor neuron -- smaller neuron, innervates intrafusal fibers regulating α-运动神经元 γ-运动神经元 muscular tonus---调节肌张力 ③ Renshaw’s cell -- 抑制α-神经元 肌梭

◇ Two groups of nuclei ① 前角内侧核 Medial nuclear group -- present in most segments of spinal cord, innervating axial muscles ② 前角外侧核 Lateral nuclear group -- present only in cervical and lumbosacral enlargements, innervating limb muscles

□ Three kinds of fibers n Ascending fibers n descending fibers n fasciculus proprius

上行纤维束 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）

1 薄束 Fasciculus Gracilis 楔束 Fasciculus Cuneatus Conduct Proprioceptive and fine touch sensation 传导意识性本体觉和精细触觉。 1) 薄束 fasciculus gracilis Arises from spinal ganglion cell below T 4 Terminates the Gracile nucleus 薄束核 2) 楔束 fasciculus cuneatus Arises from spinal ganglion cell above T 4； Terminates the Cuneate nucleus 楔束核

◆ Function Carries sensations of Two-point discrimination 两点辨别觉 Proprioception 本体觉 包括：肌肉、肌腱和关节 的位置觉、运动觉和振动觉

Two-Point Discrimination

2 脊髓丘脑束 Spinothalamic Tract Conduct Pain, temperature and simple touch sensation of trunk and limbs 脊髓丘脑侧束传导对侧躯干和四肢的痛、温 觉。脊髓丘脑前束传导躯干和四肢的粗触、压觉 Origin Laminae Ⅰ, Ⅳ~VIII of collateral spinal cord ◆ 对侧脊髓灰质I、IV—VIII Termination Dorsal thalamus 脊髓丘脑侧束 ◆ 同侧丘脑腹后外侧核 脊髓丘脑前束 脊神经节

Spinothalamic tracts Lateral Spinothalamic Tract Carries pain and temperature information Anterior Spinothalamic Tract Carries light touch, pressure

3 脊髓小脑束 Spinocerebellar Tract Carries subconscious proprioceptive sensations to cerebellum ◆ 脊髓小脑后束 Posterior. Spinocerebellar Tract Origin: nucleus thoracicus Termination: Cerebellum ◆ 脊髓小脑前束 脊髓小脑后束 Anterior. Spinocerebellar Tract Origin: Laminae Ⅴ~Ⅶ Termination: Cerebellum 脊髓小脑前束 脊神经节

下行传导通路 Descending (Motor) Pathways 下行传导束 Descending tracts 内侧纵束 Longitudinal fasciculus 皮质脊髓侧束 Lateral Corticospinal Tract 红核脊髓束 Rubrospinal Tract 网状脊髓束 Reticulospinal Tract 顶盖脊髓束 Tectospinal Tract 皮质脊髓前束 Anterior 前庭脊髓束 Vestibulospinal corticospinal Tract

1 皮质脊髓束 Corticospinal tract -- Arises from the cerebral cortex Terminates in the motor neurons of spinal cord, it divided into two tract: 1) 皮质脊髓侧束 Lateral corticospinal tract ■ Position: 外侧索后部，纵贯脊髓全长。 ■ Origin: 对侧大脑皮质运动区 ■ Termination: 在延髓交叉 皮质脊髓侧束 皮质脊髓前束 外侧索 逐节段直接或间接止于同侧前角细胞 前角运动元

★ 皮质脊髓前束 Anterior corticospinal □ Function: control somatic voluntary movement 支配躯干肌的随意运动

2 红核脊髓束 Rubrospinal Tract Begins in the red nucleus, which is located at the midbrain synapse with lower motor neurons in the Laminae Ⅴ~Ⅶ of the spinal cord Function 兴奋屈肌、抑制伸肌运动 神经元，影响肢体远端肌肉的运动。

3 前庭脊髓束 Vestibulospinal l Originate in the vestibular nuclei Synapse with lower motor neurons Laminae Ⅶ~Ⅷ of the spinal cord. l l Function 兴奋伸肌、抑制屈肌运动 神经元，调节身体平衡。

The spinal cord Descending tracts Tracts Lateral Corticospinal 皮质脊髓侧束 origin Vestibulospinal 前庭脊髓束 Termination Function Laminae Cerebral cortex Lateral Funiculus Ⅳ~Ⅸ Anterior corticospinal Cerebral cortex 皮质脊髓前束 Rubrospinal 红核脊髓束 position Red nucleus vestibular nuclei Ant. Funiculus Voluntary mov. Ant. horn Lateral Funiculus Laminae Ⅴ~Ⅶ Ant. Funiculus Laminae Ⅶ~Ⅷ Excite flexor motor neurons Excite extensor motor neurons

Descending tracts Tracts origin Reticulospinal Reticular formation 网状脊髓束 position Ant. , lateral Funiculus Longitudinal fasciculus 内侧纵束 Vestibular nuclei Tectospinal 顶盖脊髓束 Sup. colliculus Ant. Funiculus Termination Function Laminae Ⅶ~Ⅷ LaminaeⅦ~Ⅷ Influence mov. Condinate neck with eye mov. Fasciculus Spinal cord proprius 固有束 LaminaeⅥ~Ⅷ Spinal cord Intrinsic Ant. , pos. lateral Spinal cord Funiculus reflex mechanism of spinal cord

Ascending tracts Tract Site of origin Fasciculus gracilis Spinal ganglia below segment T 5 Fasciculus cuneatus Spinal ganglia above segment T 4 Posterior spinocerebellar Homolateral nucleus thoracicus Anterior spinocerebellar Spinothalamic Funiculus Termination Gracile nucleus Posterior Cuneate nucleus Lateral and anterior Convey proprioceptive and fine touch sensation of trunk and limbs Cerebellum Unconscious proprioception from lower limb and lower portion of trunk Dorsal thalamus Pain, temperature and simple touch sensation of trunk and limbs Contralateral Laminae Ⅴ~Ⅶ Laminae Ⅰ, Ⅳ~Ⅶ Function

三 Function of spinal cord 1 传导 Conduction -- Convey afferent impulses to the brain; conduct efferent impulses from the brain to the effectors. 2 反射 Reflexes Somatic reflex ◆ stretch reflex 牵张反射 ◇ 内脏反射 Visceral reflex Reflex of bladder Rectal emptying reflex ◇ 躯体反射