感覺系統(tǒng)癥狀

1、感覺神經(jīng)系統(tǒng)癥狀,鄭州大學(xué)第一附屬醫(yī)院神經(jīng)內(nèi)科苗 旺,GENERAL PROPERTIES OF SENSORY SYSTEMS,Figure 10-4: Sensory pathways,1. SENSORY RECEPTORS,A: Free nerve endings (pain, temperature)B: Pacinian corpuscle (pressure)C: Meissner’s corpuscle

2、 (touch)D: Muscle spindle (stretch),SENSORY RECEPTOR TYPES,Figure 10-1: Sensory receptors,Ruffini's endings respond to tension and stretch in the skin,SEGMENTAL INNERVATION (DERMATOMES)PERIPHERAL INNERVATION,感覺傳導(dǎo)路

3、由三級神經(jīng)元組成： 第Ⅰ級神經(jīng)元:胞體位于脊髓后根神經(jīng) 節(jié)或腦神經(jīng)感覺神經(jīng)節(jié) 第Ⅱ級神經(jīng)元:胞體位于脊髓后角細(xì)胞及延髓薄束核、楔束核或腦干腦神經(jīng)核 第Ⅲ級神經(jīng)元:胞體位于丘腦感覺接替核,SPINOTHALAMIC PATHWAY,Carries pain, temperature, touch and pressure signals1st neuron enters spinal cord through dorsal

4、 root2nd neuron crosses over in spinal cord; ascends to thalamus3rd neuron projects from thalamus to somatosensory cortex,2.淺感覺傳導(dǎo)路:前外側(cè)系統(tǒng) the anterolateral system (先交叉，后上行)輕觸-壓覺,痛覺,溫度覺的傳入纖維↓經(jīng)后根節(jié)外側(cè)部(細(xì)纖維部分)↓進(jìn)入脊

5、髓后角并于此換元↓換元后的第Ⅱ級神經(jīng)元發(fā)出纖維↓在中央管前交叉到對側(cè)↓沿脊髓丘腦前束、脊髓丘腦側(cè)束↓上行到達(dá)丘腦感覺接替核,,SOMATIC PATHWAYS,Figure 10-9: Sensory pathways cross the body’s midline,Spinothalamic Pathway,Small sensory fibres:Pain, temperature, some touch,,P

6、rimary somatosensory cortex (S1),Thalamus,Medulla,Spinal cord,Spinothalamic tract,Impulses transmitted to spinal cord byMyelinated Aδ nerves: fast pain (80 m/s)Unmyelinated C nerves: slow pain (0.4 m/s),Impulses ascend

7、 to somatosensory cortex via:Spinothalamic pathway (fast pain)Reticular formation (slow pain),SPINOTHALAMIC DAMAGE,,請同學(xué)們屈起右腿右手放在桌子上閉上眼睛按指令完成動作,2.2 DORSAL COLUMN PATHWAY,Carries fine touch, vibration and conscious pr

8、oprioception signals1st neuron enters spinal cord through dorsal root; ascends to medulla (brain stem)2nd neuron crosses over in medulla; ascends to thalamus3rd neuron projects to somatosensory cortex,三者的傳入沖動↓經(jīng)后根節(jié)外側(cè)

9、部(粗纖維部分)↓進(jìn)入脊髓后角↓沿同側(cè)后索上行↓抵達(dá)延髓下部在薄束核、楔束核換神經(jīng)元↓換元后的第Ⅱ級神經(jīng)元發(fā)出纖維↓交叉到對側(cè)↓沿內(nèi)側(cè)丘系↓到達(dá)丘腦感覺接替核。,,dorsal cloumnpathway,Dorsal column pathway,Large sensory nerves:Touch, vibration, two-point discrimination, propriocepti

10、on,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,SEN

11、SORY MODALITY,Figure 10-6: Lateral inhibition,DORSAL COLUMN DAMAGE,DORSAL COLUMN DAMAGE,Sensory ataxiaPatient staggers; cannot perceive position or movement of legsVisual clues help movement,由于傳導(dǎo)痛覺、溫度覺的傳入纖維在進(jìn)入脊髓后→在進(jìn)入

12、水平的 1-2個節(jié)段內(nèi)更換神經(jīng)元并交叉到對側(cè)；而傳導(dǎo)輕觸(- 壓)覺的傳入纖維在進(jìn)入脊髓后分成上行和下行纖維，分別在多個節(jié)段內(nèi)更換神經(jīng)元并交叉到對側(cè)，因而發(fā)生上述痛、溫覺受損而觸覺保留現(xiàn)象。,3.頭面部的感覺傳導(dǎo)路： Facial sensory pathway,觸覺、本體感覺的傳入沖動 ↓三叉神經(jīng)主核、中腦核中繼換元,痛覺、溫度覺的傳入沖動 ↓三叉神經(jīng)脊束核中繼換元,發(fā)出第Ⅱ級纖

13、維→越至對側(cè)→三叉丘系→丘腦后內(nèi)側(cè)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 extr

14、emitiesDorsal root ganglia or radicular laesions:segmental, localised to dermatomes,SENSORY SYNDROMES 2.,Spinal cord:-complete cord lesion-hemisection of spinal cord : Brown – Sequard syndrome-central cord lesi

15、on (Syringomyelia, dissociated sensory loss: loss of pain and temperature, preservation of proprioception)-posterior tract lesion (funicular myelosis: loss of proprioception, ataxia)-conus laesion (sen

16、sory loss of sacral area, “saddle anaesthesia)Brain stem: Wallenberg syndromeThalamus: Dejerine – Roussy syndrome (contralateral hemihypaesthesia, ataxia, pain)Sensory cortex: contralateral hemihypaesthesia,SE