人體剖學神經傳導通路課件

1、神經傳導通路 Nervous Pathways 中樞神經系統(tǒng) Central Nervous SystemHuman Anatomy神經傳導通路中樞神經系統(tǒng) Central Nervous Central Nervous System Section 3 The Nervous Pathways Central Nervous System SectioGeneral Description Nervous pathways are routes formed by chains of neurons. They are classified into: Sensory pathways (a

2、scending) & Motor pathways (descending). General Description Receptor EffectorCentreEfferentAfferentReflex ArcInt, Ext EnvironmentHigher CentreResponsesReceptor EffectorCentreEffer In most sensory pathways there are three orders of neurons involved: Lower sensory neurons - the ganglia Intermediate n

3、eurons - the spinal cord or brain stem Upper sensory neurons - the thalamusspinothalamicpathway( Deep and Superficial sensory, Visual and Acoustic Pathways )I.感覺傳導路 Sensory (ascending) Pathway In most sensory pathways t1st neurons 2nd neurons 3rd neurons 1st neurons 2nd neurons 3rd ) Deep sensory (

4、or proprioceptive ) pathwaysProprioceptive including: (1) the sensations of body posture (2) the movement (3) the vibration (4) the fine touch sensation - two-point discrimination) Deep sensory ( or proprioce1. 軀干四肢意識性深感覺傳導路 The conscious deep sensory pathways of trunk and limbsreceptors muscle, ten

5、don, periosteum, joint, and skinperipheral processes spinal nerve spinal ganglia 1st neurons fasciculus gracilis & cuneatus central processes, posterior funiculus 2nd neurons gracile & cuneate nuclei decussation of lemniscus & medial lemnisci ventroposterior lateral nucleus 3rd neurons posterior lim

6、b of internal capsule thalamocortical tract brain stempostcentral gyrus, posterior part of paracentral lobule and precentral gyrus 1. 軀干四肢意識性深感覺傳導路 The consciousSpinal ganglion 1neuron Fasciculus gracilis Fasciculus cuneatus Gracile & cuneate nuclei2neuron Decussation of medial lemniscusMedial lemni

7、scusVPL 3neurons Central thalamic radiation T4updownpostcentral gyrus, posterior part of paracentral lobule and precentral gyrusConscious deep sensory pathways of trunk and limbsSpinal ganglion Fasciculus grLesion & Appearance(1)(2) (1) Interruption of pathways by lesions below level of decussation

8、numbness on the affected side of body below the lesion level (2) Interruption above level of decussation - hemianesthesia on the opposite side of the bodyLesion & Appearance(1)(2) (dorsal column pathwayLHSspinal cord injuryLoss of sense of: fine touch proprioception vibrationin left legDorsal column

9、 damagedorsal column LHSLoss of senseAppearance of Dorsal Column Damage Sensory ataxia Patient staggers cannot perceive position or movement of legs Visual clues help movementAppearance of Dorsal Column Da2. 軀干四肢非意識性深感覺傳導路 The unconscious deep sensory pathways of trunk and limbsmuscle, tendon, perio

10、steum, and jointreceptors peripheral processes spinal nerve spinal ganglia 1st neurons central processes dorsal roots thoracic N. and intermedio-medial N. 2nd neurons anterior or posterior spinocerebellar tracts superior and inferior cerebellar peduncles paleocerebellum or spinocerebellum to maintai

11、n the coordination movement and equilibrium and appropriate posture of the body 3. The deep sensory pathway of head and face The exact route of this pathway is still not known.No 3rd neuron to cortex, hence unconscious( Carries unconscious proprioception signals )2. 軀干四肢非意識性深感覺傳導路 The unconsciUncons

12、cious proprioceptive pathwaySpinal ganglion Posterior spinocerebellar tract Anterior Spinocerebellartract Lamina - Inferior cerebellar peduncleSuperior cerebellar peduncleNucleus thoracicusupdownPaleocerebellumUnconscious proprioceptive pLesion & Appearance Cerebellar ataxia Clumsy movements Incoord

13、ination of the limbs (intention tremor) Wide-based, reeling gait (ataxia) Alcoholic intoxication produces similar effects!Lesion & Appearance Cerebell ) Superficial sensory pathways( pain, thermal, rude tactile, and pressure sensation )Primary somatosensory cortex (S1)Thalamus ( Intralaminar and VP

14、nuclei )MedullaSpinothalamic tractSpinal cordSmall sensory fibres:Pain, temperature, some touch and pressure sensation ) Superficial sensory pathwareceptors skinspinal nerve peripheral processes spinal ganglia 1st neurons central processes nucleus proprius lamina I. IV. V. 2nd neurons cross to oppos

15、ite side anterior white commissure lateral & anterior spinothalamic tract lateral funiculus runs up to brain stem3rd neurons VPLpostcentral gyrus, posterior part of paracentral lobule posterior limb of internal capsule thalamocortical tract 1. 軀干四肢淺感覺傳導路 The superficial sensory pathways of trunk and

16、 limbs dorsal roots Lissauers fasciculus asend 12 segmentsreceptors skinspinal nerve per Spinal ganglia1neuron nucleus proprius Lamina, 2neuron Lateral spinothalamic tract anterior spinothalamic tract Spinal lemniscusVPL 3neurons Central thalamic radiationupdownSuperficial sensory pathways of trunk

17、and limbspostcentral gyrus & posterior part of paracentral lobule Spinal ganglianucleus nociceptornociceptorA nerveC nervespinothalamicpathwayto reticularformationreticular formationspinothalamicpathwaythalamussomato-sensorycortexImpulses transmitted to spinal cord by Myelinated A nerves: fast pain

18、(80 m/s) Unmyelinated C nerves: slow pain (0.4 m/s)Impulses ascend to somatosensory cortex via: Spinothalamic pathway (fast pain) Reticular formation (slow pain)nociceptornociceptorA nerveC *Lesion and Appearance(1) Interruption of pathways by lesions at anterior white commissure to causes Symmetric

19、al hypesthesia(2) Interruption of pathways by lesions in the lateral funiculus of the spinal cord Brown-Sequard Syndrome (3) Interruption of pathways by lesions in the internal capsule to causes Hemihypesthesia (1)(2)(3)*Lesion and Appearance(1) InteSpinothalamic damagespinothalamic pathwayLHSspinal

20、 cord injuryLoss of sense of:TouchPainWarmth/coldin right legSpinothalamic damagespinothalaBrown-Sequard SyndromeBrown-Sequard Syndromereceptors skin mucosa sensory branches of trigeminal nerve peripheral processes trigeminal ganglion 1st neurons central processes spinal nucleus & pontine nucleus of

21、 trigeminal n.2nd neurons cross to opposite side3rd neurons VPM inferior part of postcentral gyrusposterior limb of internal capsule thalamocortical tract sensory root of trigeminal n. spinal tract of trigeminal n.to join trigeminal lemniscus2. 頭面部的淺感覺傳導路 The superficial sensory pathways of head and

22、 face receptors skin mucosa sensoryTrigeminal ganglion1neuron Pontine nucleus of V 2neuronSpinal nucleus of V 2neuronTrigeminal lemniscus Spinal tract of trigeminal n. VPM 3neurons Central thalamic radiation updown pain, temperature and simple touch pathway of head and faceTrigeminal ganglion Pontin

23、e nu*Lesion and Appearance(1) Interruption of pathways by lesions at trigeminal n., trigeminal ganglion, trigeminal root, and spinal tract & spinal nucleus of trigeminal n. (2) Interruption of pathways by lesions in trigeminal lemniscus, VPM, internal capsule ( thalamocortical tract ), and inferior

24、part of postcentral gyrus(1)(2)*Lesion and Appearance(1) Inte) Visual pathwaysOptic nerveOptic tractLateral geniculate nucleusOptic radiationOptic chiasmPrimary visual cortex) Visual pathwaysOptic nerveO人體剖學神經傳導通路課件1. 視覺傳導路 The visual pathwayreceptors rod & cone cells external layer of retinaperiphe

25、ral processes bipolar cells1st neurons central processes ganglionic cells2nd neurons optic nerve optic chiasma optic tract 3rd neurons lateral geniculate body both banks of the calcarine sulcusposterior limb of internal capsule optic radiation middle layer of retinadecussation of fibers from nasal h

26、alves of retina innermost layer of retinaaxons optic disc visual area1. 視覺傳導路 The visual pathwayrec Visual pathwayVisual areaOptic nerveOptic chiasmaOptic tractLateral geniculate bodyOptic radiation Visual pathwayVisual areaOpti*Lesion and AppearanceInterruption of pathways by lesions in: 1. Optic n

27、erve 2. Optic chiasma -pituitary tumor 3. Optic tract, Lateral geniculate body, and Optic radiation Complete blindness Bitemporal hemianopia hemianopia of opposite halves of both visual fieldsABC*Lesion and AppearanceInterrup2. 瞳孔對光反射通路 The pathway of pupillary reflexespostganglionic fibersRetinaaxo

28、ns of retinal ganglion cellsOptic nerveOptic chiasmaBoth optic tractdecussation of fibers from nasal halvesbrachium of superior colliculusPretectal areaE-W nucleusto both sideOculomotor n.Ciliary ganglionSphincter of pupilspreganglionic fibers to form2. 瞳孔對光反射通路 The pathway of pupPretectal area E-W

29、nucleusOccculomotor n.Ciliary ganglia Sphincter pupil muscle Pathway of pupillary reflexesPretectal area E-W nucleusOcccLight shone on retina of one eye causes both pupils to constrict normally Response in Stimulated eye - direct pupillary light reflex Opposite eye - indirect pupillary light reflex1

30、. Optic nerve damage To disappear direct pupillary light reflex To be present indirect pupillary light reflex 2. Oculomotor nerve damage Both to disappear direct pupillary light reflex & indirect pupillary light reflex*Lesion and Appearance12Light shone on retina of one evisual centerlightpretectal

31、areaE-W nucleusvisual pathwaylight reflexlateral genicular body( area 17 )sphincter of irisretina two sidesposterior limb of internal capsulevisual radiationcone & rod cellsBipolar cellsGanglionic cellsOptic NOptic chiasmaOptic tractSummary for visual pathway ciliary ganglionvisual centerlightpretec

32、tal arIV) Acoustic ( or auditory ) pathwayIV) Acoustic ( or auditory ) p聽覺傳導路 The visual pathwayreceptors spiral organ ( Cortis organ) in internal ear bipolar cellsperipheral processes cochlear ganglion 1st neurons central processes cochlear nuclei2nd neurons terminate directly or indirectly to 3rd

33、neurons medial geniculate body both transverse temporal gyriposterior limb of internal capsule acoustic radiation cochlear nerveboth side fibers( decussed & undecussed fibers )acoustic centertrapezoid body lateral lemniscus 聽覺傳導路 The visual pathwayreceptBipolar neuron of cochlear ganglion Cochlear n

34、erveCochlear nucleiTrapezoid body Lateral lemniscus Medial geniculate body Acoustic radiation Transverse temporal gyrusAuditory pathwaySpiral organ Because acoustic center on one side receives fibers from bilateral cochlear nuclei, damage to ipsilateral acoustic paths does not cause a hearing defect

35、.Bipolar neuron of Cochlear ner joining medial longitudinal fasciculus joining vestibulospinal tractVestibular nucleus) Equilibratory pathwayOculomotornucleusTrochlearnucleusAbducentnucleusAccessorynucleus joining medial longitudinal receptors cristae ampullares, maculae of utricle and sacculebipola

36、r cellsperipheral processes vestibular ganglion 1st neurons central processes vestibular nucleus2nd neurons vestibular nerve axons are grouped into five courses: joining medial longitudinal fasciculus fibers end in oculomotor, abducent, trochlear nuclei, and anterior horn cells of upper cervical cor

37、d joining vestibulospinal tract to anterior horn cells of spinal cord entering cerebellum via inferior cerebellar peduncle connecting with reticular formation of brain stem, vagus and glossopharyngeal nuclei connecting with temporal, parietal and frontal cortex of hemisphere 平衡覺傳導路 The equilibratory

38、 pathwayreceptors cristae ampullares, Equilibratory pathwayEquilibratory pathwayII.運動傳導路 Motor (descending) Pathway ( Including pyramidal and extrapyramidal )II.運動傳導路 Motor (descending) Pa It is concerned with voluntary movement of skeletal muscles. It is composed of two orders of neurons - upper an

39、d lower motor neurons. It is to form Corticonuclear tract & Corticospinal tract Upper motor neurons Giant pyramidal cells ( Betzs cells ) & Other pyramidal cells located - precentral gyrus & paracentral lobule ) The pyramidal system It is concerned with volun Lower motor neurons (1) Cranial motor nu

40、clei of brain stem Lower motor neurons (2) Anterior horn motor cells of spinal cord (2) Anterior horn motor cells The Corticospinal Tract The Corticospinal Tract1. 皮質脊髓束 Corticospinal Tractupper motor neuron Superior, middle parts of precentral gyrus & Paracentral lobule skeletal muscles of trunk an

41、d limbs Effector posterior limb of internal capsule intermediate 3/5 of crus cerebri basilar part of pons pyramid of medulla oblongata Pyramidal tract - Corticospinal tract 7090% of tract crosses to opposite side to form pyramidal decussatlon lateral corticospinal tract ( lateral funiculus ) ( anter

42、ior funiculus ) anterior corticospinal tract smaller part of crossed fibers of tract Lower motor neuronAnterior horn motor cells of spinal cordspinal nerve 1. 皮質脊髓束 Corticospinal Tractup Corticospinal tractDecussation of pyramid Lateral corticospinal tractAnterior corticospinal tract upper motor neu

43、ron Lower motor neuronCorticospinal Tract Corticospinal tractDecussatio The Corticonuclear Tract The Corticonuclear Tract2. 皮質核束 Corticonuclear Tractupper motor neuron Pyramidal neurons in Inferior part of precentral gyrus skeletal muscles of head and neck Effector genu of internal capsule brain ste

44、m to bilateral oculomotor, trochlear, trigeminal motor, ambiguus, accessory nuclei and superior part of facial nucleus, Pyramidal tract Lower motor neuron Cranial motor nucleicorresponding cranial nerves and to contralateral hypoglossal nucleus and inferior part of facial nucleusCorticonuclear tract

45、2. 皮質核束 Corticonuclear TractupOculomotor Nucleus Trochlear Nucleus Trigeminal Motor Nucleus Abducent NucleusSup. part of Facial NucleusInf. part of Facial NucleusAmbiguus NucleusAccessory Nucleus Hypoglossal NucleusCorticonuclear TractOculomotor Nucleus TrochlInfranuclear paralysis - Injury of unila

46、teral facial nerve or hypoglossal nerve Paralysis of homolateral facial muscles and glossal muscles Supranuclear paralysis - Injury of unilateral corticonuclear tract Paralysis of contralateral glossal muscles and facial muscles below palpebral fissureSupranuclear paralysisInfranuclear paralysisInfr

47、anuclear paralysis - InjuInfranuclear paralysis - Injury of unilateral ( left ) facial nerve Infranuclear paralysis Lesion for pyramidal system1. Uni-paralysis ( cerebral paralysis ) Motor Area 2. Alternate Paralysis Brain Stem (1) Alternating oculomotor hemiplegia - Webers syndrome (2) Alternating

48、abducent hemiplegia (3) Alternating hypoglossal hemiplegia3. Paraplegia - Spinal Cord 4. Infantile Paralysis - Anterior horn motor cells of spinal cord 1. cerebral paralysis2. alternate paralysis3. paraplegia4. infantile ParalysisLesion for pyramidal system1. 5. Capsular Hemiplegia5. Capsular Hemipl

49、egiaAlternating HemiplegiaAlternating HemiplegiaBrown-Sequard SyndromeBrown-Sequard SyndromePyramidal systemPyramidal tractUpper motor neuronsInferior motor neuronseffectorsParalysisTonicityTendon reflexPathologic reflex (Babinski sign)Muscle atrophyspastic (hard)paralysis flaccid (soft) paralysis (

50、 + )No( in short period ) ( )Yes ( 下神經元不斷發(fā)放沖動 保證肌肉的營養(yǎng)代謝 )Interruption of reflex arc 錐體束對下神經元 的抑制性影響消失 disappearMotor areaLesion for pyramidal systemPeripheral nerves Somatic motor F.Pyramidal systemPyramidal tracSigns of Upper Motor Neuron (UMN)and Lower Motor Neuron (LMN) LesionsSignUMN LesionsLMN

51、Lesions ParalysisHard paralysisFlaccid paralysisToneIncreasedDecreasedTendon reflexDisappearBabinski signYesNoAtrophyNo*Yes*Mild atrophy may develop due to disuse.IncreasedSigns of Upper Motor Neuron (U) The extrapyramidal system1. The definition: descending pathways except pyramidal system 2. The features:發(fā)生古老,多次中繼,聯(lián)系復雜, 形成若干反饋通路3. The functions: Regulate the tonicity of the muscles Coordinate the muscular activity Maintain the normal posture Produce habitual and rhythmic movement4. The constituent for extr