1. The Nervous System
山东大学医学院 解剖教研室
李振华

2. Divisions
Central nervous system (CNS)
Peripheral nervous system (PNS)

3. 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

4. Peripheral nervous system (PNS)
Cranial n. (12 pairs) 脑神经
Spinal n. (31 pairs) 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

5. Cellular organization
Neurons 神经元
Cell body 胞体
Axon 轴突
Dendrites 树突
Neuroglia －glial cell胶质细胞

6. 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 branch 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

7. Reflex and reflex arc
Reflex: a reaction of the organism by the nervous system in response to a stimulus
Reflex arc: has 5 basic components
Receptor ↓
Sensory neurons
CNS
Moter neurons
Effector

8. Basic terminology in nervous system

9. 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 cerebrum 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

10. Fasciculus 纤维束( tract ): a bundle 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

11. In the PNS
Ganglion 神经节: a collection of neuronal cell bodies outside the CNS
Nerve 神经: a bundle of nerve fibers held together by connective tissue sheath

12. 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

13. External features
A long cylindrical structure and 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

14. Fissure and sulci Anterior median fissure 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

15. Relationship of segments of spinal 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

16. Relationship of segments of spinal cord to vertebrae
Spinal segments
Vertebral levels (spines)
Upper cervical region (C1~C4)
= C1 ~ C4
Lower cervical and upper thoracic region (C5~T4)
— 1 = C4 ~ T3
Middle thoracic region (T5~T8)
— 2 = T3 ~ T6
Lower thoracic region (T9~T12)
— 3 = T6 ~ T9
Lumber segments
= T10 ~ T12
Sacral and coccygeal segments
= L1

17. Internal structures Central canal 中央管 Gray matter White matter
Anterior horn (column) 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

18. Posterior horn (column):
Marginal layer （缘层）
Substantia gelatinosa （胶状质）
Nucleus proprius （后角固有核）
Nucleus thoracicus（胸核） in segments C8~L3

19. Intermediate zone
Intermediaolateral nucleus （中间外侧核）(lateral horn or column): lies in segments T1~L3, containing sympathetic preganglionic neurons
Sacral parasympathetic nucleus（骶副交感核）: lies in segments S2~S4, containing parasympathetic preganglionic neurons
Intermediomedial nucleus （中间内侧核） : for sensation of viscera

20. Anterior horn (column): contain motor neurons
Three kinds of neuron
α-motor neuron: larger multipolar neuron, innervates extrafusal fibers of skeletal m., producing contraction of m.
γ-motor neuron: smaller neuron, innervates intrafusal fibers regulating muscular tonus
Renshaw’s 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 lumbosacral enlargements, innervating limb muscles

21. Rexed’s lamina 板层 posterior horn is formed by lamina Ⅰ to Ⅵ；
Intermediate zone corresponding to lamina Ⅶ；
Anterior horn is composed laminae Ⅷ and Ⅸ；
lamina Ⅹ is the gray matter surrounding the central canal.

22. Important Subdivision of Spinal Cord Gray Matter
Region
Lamina
Nucleus
Posterior horn Ⅰ
Marginal layer Ⅱ
Substantia gelatinosa
Ⅲ, Ⅳ
Nucleus proprius
Intermediate zone Ⅶ
Nucleus thoracicus (C8~L3)
Intermediolateral nucleus (T1~L3)
Sacral parasympathetic nucleus (S2~S4)
Intermediomedial nucleus
Anterior horn Ⅸ
Motor neuron

23. Ⅲ) White matter
White matter contains three kinds of fibers: ascending, descending, and fasciculus proprius

24. 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）

27. Ascending tracts Tract Site of origin Funiculus Termination Function
Fasciculus gracilis
Spinal ganglia below segment T5
Posterior
Gracile nucleus
Convey proprioceptive and fine touch sensation of trunk and limbs
Fasciculus cuneatus
Spinal ganglia above segment T4
Cuneate nucleus
Posterior spinocerebellar
Homolateral nucleus thoracicus
Lateral
Cerebellum
Unconscious proprioception from lower limb and lower portion of trunk
Anterior spinocerebellar
Contralateral Laminae
Ⅴ~Ⅶ
Spinothalamic
Laminae Ⅰ,
Ⅳ~Ⅶ
Lateral and anterior
Dorsal thalamus
Pain, temperature and simple touch sensation of trunk and limbs

28. Descending tracts Fasciculus proprius （固有束）
Lateral corticospinal tract
（皮质脊髓侧束）
Rubrospinal tract
（红核脊髓束）
Reticulospinal tract
（网状脊髓束）
Vestibulospinal tract
（前庭脊髓束）
Tectospinal tract
（顶盖脊髓束）
Medial longitudinal fasciculus （内侧纵束）
Anterior corticospinal tract （皮质脊髓前束）

30. Descending tracts Tract Site of origin Funiculus Termination Function
Lateral corticospinal
Cerebral cortex
Lateral
Laminae
Ⅳ~Ⅸ
anterior horn
Voluntary movement
Anterior corticospinal
Anterior
Rubrospinal
Red nucleus
Ⅶ~Ⅶ
Excitatory of flexors
Vestibulospinal
Homolateral vestibular nuclei
Ⅶ~Ⅷ
Excitatory of extensors
Reticulospinal
Reticular formation
Anterior and lateral
Medial longitudinal fasciculus
Vestibular nuclei
Coordinate neck with eye movement
Tectospinal
Superior colliculus
Ⅵ~Ⅷ
Fasciculus proprius
Spinal cord
Anterior, lateral and posterior
Intrinsic reflex mechanism of spinal cord

32. Main functions of spinal cord
Conduction of excitations
Reflex activity