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1、感觉神经系统症状,GENERAL PROPERTIES OF SENSORY SYSTEMS,Figure 10-4:Sensory pathways,1.SENSORY RECEPTORS,A:Free nerve endings(pain,temperature)B:Pacinian corpuscle(pressure)C:Meissners corpuscle(touch)D:Muscle spindle(stretch),SENSORY RECEPTOR TYPES,Figure 10-1:Sensory receptors,Ruffinis endings respond to t
2、ension and stretch in the skin,SEGMENTAL INNERVATION(DERMATOMES)PERIPHERAL INNERVATION,感觉传导路由三级神经元组成：第级神经元:胞体位于脊髓后根神经 节或脑神经感觉神经节 第级神经元:胞体位于脊髓后角细胞及延髓薄束核、楔束核或脑干脑神经核 第级神经元:胞体位于丘脑感觉接替核,SPINOTHALAMIC PATHWAY,Carries pain,temperature,touch and pressure signals1st neuron enters spinal cord through dorsal r
3、oot2nd neuron crosses over in spinal cord;ascends to thalamus3rd neuron projects from thalamus to somatosensory cortex,2.浅感觉传导路:前外侧系统 the anterolateral system(先交叉，后上行)轻触-压觉,痛觉,温度觉的传入纤维经后根节外侧部(细纤维部分)进入脊髓后角并于此换元换元后的第级神经元发出纤维在中央管前交叉到对侧沿脊髓丘脑前束、脊髓丘脑侧束上行到达丘脑感觉接替核,SOMATIC PATHWAYS,Figure 10-9:Sensory pathw
4、ays cross the bodys midline,Spinothalamic Pathway,Small sensory fibres:Pain,temperature,some touch,Primary somatosensory cortex(S1),Thalamus,Medulla,Spinal cord,Spinothalamic tract,Impulses transmitted to spinal cord byMyelinated A nerves:fast pain(80 m/s)Unmyelinated C nerves:slow pain(0.4 m/s),Imp
5、ulses ascend to somatosensory cortex via:Spinothalamic pathway(fast pain)Reticular formation(slow pain),SPINOTHALAMIC DAMAGE,请同学们屈起右腿右手放在桌子上闭上眼睛按指令完成动作,2.2 DORSAL COLUMN PATHWAY,Carries fine touch,vibration and conscious proprioception signals1st neuron enters spinal cord through dorsal root;ascends
6、 to medulla(brain stem)2nd neuron crosses over in medulla;ascends to thalamus3rd neuron projects to somatosensory cortex,三者的传入冲动经后根节外侧部(粗纤维部分)进入脊髓后角沿同侧后索上行抵达延髓下部在薄束核、楔束核换神经元换元后的第级神经元发出纤维交叉到对侧沿内侧丘系到达丘脑感觉接替核。,dorsal cloumnpathway,Dorsal column pathway,Large sensory nerves:Touch,vibration,two-point dis
7、crimination,proprioception,Primary somatosensory cortex(S1)in parietal lobe,Thalamus,Medulla,Mediallemniscus,Spinal cord,Dorsal column,Dorsal columnnuclei,TWO-POINT DISCRIMINATION,SENSORY MODALITY,Figure 10-3:Two-point discrimination,SENSORY MODALITY,Figure 10-6:Lateral inhibition,DORSAL COLUMN DAMA
8、GE,DORSAL COLUMN DAMAGE,Sensory ataxiaPatient staggers;cannot perceive position or movement of legsVisual clues help movement,由于传导痛觉、温度觉的传入纤维在进入脊髓后在进入水平的 1-2个节段内更换神经元并交叉到对侧；而传导轻触(-压)觉的传入纤维在进入脊髓后分成上行和下行纤维，分别在多个节段内更换神经元并交叉到对侧，因而发生上述痛、温觉受损而触觉保留现象。,3.头面部的感觉传导路：Facial sensory pathway,触觉、本体感觉的传入冲动 三叉神经主核、
9、中脑核中继换元,痛觉、温度觉的传入冲动 三叉神经脊束核中继换元,发出第级纤维越至对侧三叉丘系丘脑后内侧腹核,SENSORY SYNDROMES 1.,Peripheral nerve:according to the distribution area of the affected nervePolyneuropathy:glove stocking distribution,more pronaunced distaly,more on the lower extremitiesDorsal root ganglia or radicular laesions:segmental,loca
10、lised to dermatomes,SENSORY SYNDROMES 2.,Spinal cord:-complete cord lesion-hemisection of spinal cord:Brown Sequard syndrome-central cord lesion(Syringomyelia,dissociated sensory loss:loss of pain and temperature,preservation of proprioception)-posterior tract lesion(funicular myelosis:loss of propr
11、ioception,ataxia)-conus laesion(sensory loss of sacral area,“saddle anaesthesia)Brain stem:Wallenberg syndromeThalamus:Dejerine Roussy syndrome(contralateral hemihypaesthesia,ataxia,pain)Sensory cortex:contralateral hemihypaesthesia,SENSORY SYNDROMES SPINAL GANGLION,SENSORY SYNDROMES FUNICULAR MYELOSIS,SENSORY SYNDROMES,SENSORY SYNDROMES,SENSORY SYNDROMES,SENSORY SYNDROMES,谢谢,
