第三节神经系统的传导通路

1、The Motor Pathways 运 动 传 导 路,（一） Pyramidal System 锥体系,The motor pathways are concerned with motor function, include pyramidal system 锥体系 extrapyramidal system 锥体外系,It concerned with voluntary moveme

2、nt 随意运动of the skeletal m. and is composed of two orders of neurons: upper motor neuron 上运动神经元lower motor neuron 下运动神经元,upper motor neuron,lower motor neuron,effector,,,,,The pyramidal system consists of corticospina

3、 tract 皮质脊髓束 corticonuclear tract 皮质核束,upper motor neuron,lower motor neuron,effector,Upper Motor Neurons,lie in the motor area of cerebral cortex, Connect directly or through interneurons to lower motor neurons,,Lower

4、 Motor Neurons,include cranial motor nuclei and motor neurons in anterior horn of spinal cord. their axons leave the CNS and extend though peripheral nerves to supply skeletal muscles,,Corticospinal tract,,Corticospin

5、al tract,,Decussation of pyramid,,Lateral corticospinal tract,,Anterior corticospinal tract,,upper motor neuron,upper motor neuron is the Giant pyramidal cells (Betz cells) 巨大锥体细胞 and other pyramidal cells in superior 2/

6、3 of precentral gyrus and ant. part of paracentral lobule,,1. Corticospinal Tract 皮质脊髓束,,,,,,,,Lower motor neuron is the Motor neurons of anterior horn of spinal cord,2.Corticonuclear Tract 皮质核束,,,,,,Giant pyramidal

7、cells and other pyramidal cells in lower 1/3 of precentral gyrus,Genu of internal capsuleBrain stem,,Cranial nerves,Bilateral： nucleus of oculomotor n., nucleus trochlear n., motor nucleus of trigeminal n.,

8、 nucleus of abducent n. ambiguus nucleus, nucleus of accessory n. superior part of facial nucleus.,,,,,,,,,,,The Corticonuclear tract send out fibers to end,Contralateral: inferior part of facial nucleus 面神经核下

9、半hypoglossal nucleus 舌下神经核.,,,,,,,,,,,,,,Corticonuclear tract,,hypoglossal nucleus and inferior part of facial nucleus receive only the fibers from the contralateral corticonucleal tract.,facial nucleus,hypoglossal

10、nucleus,,The injury of the unilateral corticonuclear tract can usually cause the paralysis of the contralateral glossal m. and facial m. below the palpebral fissure. The paralysis caused by the injury of the upper m

11、otor neuron is called supranuclear paralysis 核上瘫; The paralysis caused by the injury of the lower motor neuron is called the infranuclear paralysis 核下瘫,,infranuclear paralysis of facial n. 面神经核下瘫,supranuclear p

12、aralysis of facial n. 面神经核上瘫 ---- the paralysis of facial m. in opposite side below the pelpebral fissure 对侧睑裂以下面肌瘫痪,---- the paralysis of facial m. of same side 同侧面肌瘫,,supranuclear paralysis of hypoglossal n.舌下神

13、经核上瘫 ----when tongue extend, the apex of tongue inclined to the opposite side,Effects of Upper and Lower Motor Neuron Damage,（二） Extrapyramidal System 锥体外系,composision：the extrapyramidal System include the following

14、structures,Cerebral cortex、corpus striatum 纹状体、dorsal thalamus、subthalamus、red necleus、substantia nigra、pontine neuclei脑桥核、vestibular neuclei、cerebelum、reticular formation and the fibers connection among them.,（二） Extrap

15、yramidal System 锥体外系,2. character,,,,,新纹状体—黑质环路,,,,皮质—新纹状体—丘脑—皮质环路,1、The cortico-neosstriated body-dorsothalamus –cortex circuit,2、The neostriated body-subsantia nigra circuit,对皮质运动区有反馈调节作用,多巴胺能通路，损伤可致震颤麻痹,,,,,,皮质- 脑桥 -

16、小脑 - 皮质环路,3、the corticoponto-cerebellar-cortex circuit,协调随意运动，损伤表现共济失调,4. 锥体系损伤及表现：,①脊髓前角及脊神经损伤：,软瘫 flaccid paralysis,②脊髓外侧索损伤：,同侧损伤平面以下硬瘫 hard paralysis,③延髓锥体交叉以上处损伤：,对侧上、下肢硬瘫,,,,,,,,如内囊损伤,,,,1. Injury of the internal c

17、apsule,,1. Injury of the spinal cord,3. Upper、Lower Motor Neurons 上、下运动神经元,① Upper motor Neurons:,指大脑皮质的锥体细胞及其轴突,② Lower motor Neurons:,指脊髓前角细胞和脑神经运动核细胞,③上运动神经元损伤（核上瘫 supranuclear paralysis)：在皮质脊髓束表现为硬瘫(hard paralysis),

18、即,肌张力(tonicity of muscles)增高、肌肉不萎缩(without atrophy)、深反射亢进、出现病理反射等；在皮质核束表现为：即对侧眼裂以下的面肌瘫痪和舌肌瘫痪（伸舌时舌尖偏向对侧）。,④下运动神经元损伤（核下瘫 infranuclear paralysis)：在皮质脊髓束表现为 软瘫 ( flaccid paralysis or soft paralysis).，,即肌张力降低、肌肉萎缩(muscles at