人體解剖學(xué)-神經(jīng)傳導(dǎo)通路課件

1、神經(jīng)傳導(dǎo)通路 Nervous Pathways 中樞神經(jīng)系統(tǒng) Central Nervous SystemHuman AnatomyCentral Nervous System Section 3 The Nervous Pathways General Description Nervous pathways are routes formed by chains of neurons. They are classified into: Sensory pathways (ascending) & Motor pathways (descending). Receptor Effector

2、CentreEfferentAfferentReflex ArcInt, Ext EnvironmentHigher CentreResponses In most sensory pathways there are three orders of neurons involved: Lower sensory neurons - the ganglia Intermediate neurons - the spinal cord or brain stem Upper sensory neurons - the thalamusspinothalamicpathway( Deep and

3、Superficial sensory, Visual and Acoustic Pathways )I.感覺傳導(dǎo)路 Sensory (ascending) Pathway1st neurons 2nd neurons 3rd neurons ) Deep sensory ( or proprioceptive ) pathwaysProprioceptive including: (1) the sensations of body posture (2) the movement (3) the vibration (4) the fine touch sensation - two-po

4、int discrimination1. 軀干四肢意識(shí)性深感覺傳導(dǎo)路 The conscious deep sensory pathways of trunk and limbsreceptors muscle, tendon, periosteum, joint, and skinperipheral processes spinal nerve spinal ganglia 1st neurons fasciculus gracilis & cuneatus central processes, posterior funiculus 2nd neurons gracile & cunea

5、te nuclei decussation of lemniscus & medial lemnisci ventroposterior lateral nucleus 3rd neurons posterior limb of internal capsule thalamocortical tract brain stempostcentral gyrus, posterior part of paracentral lobule and precentral gyrus Spinal ganglion 1neuron Fasciculus gracilis Fasciculus cune

6、atus Gracile & cuneate nuclei2neuron Decussation of medial lemniscusMedial lemniscusVPL 3neurons Central thalamic radiation T4updownpostcentral gyrus, posterior part of paracentral lobule and precentral gyrusConscious deep sensory pathways of trunk and limbsLesion & Appearance(1)(2) (1) Interruption

7、 of pathways by lesions below level of decussation numbness on the affected side of body below the lesion level (2) Interruption above level of decussation - hemianesthesia on the opposite side of the bodydorsal column pathwayLHSspinal cord injuryLoss of sense of: fine touch proprioception vibration

8、in left legDorsal column damageAppearance of Dorsal Column Damage Sensory ataxia Patient staggers cannot perceive position or movement of legs Visual clues help movement2. 軀干四肢非意識(shí)性深感覺傳導(dǎo)路 The unconscious deep sensory pathways of trunk and limbsmuscle, tendon, periosteum, and jointreceptors peripheral

9、 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 maintain the coordination movement and equi

10、librium 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 )Unconscious proprioceptive pathwaySpinal ganglion Posterior spinocerebel

11、lar tract Anterior Spinocerebellartract Lamina - Inferior cerebellar peduncleSuperior cerebellar peduncleNucleus thoracicusupdownPaleocerebellumLesion & Appearance Cerebellar ataxia Clumsy movements Incoordination of the limbs (intention tremor) Wide-based, reeling gait (ataxia) Alcoholic intoxicati

12、on produces similar effects! ) Superficial sensory pathways( pain, thermal, rude tactile, and pressure sensation )Primary somatosensory cortex (S1)Thalamus ( Intralaminar and VP nuclei )MedullaSpinothalamic tractSpinal cordSmall sensory fibres:Pain, temperature, some touch and pressure sensation rec

13、eptors skinspinal nerve peripheral processes spinal ganglia 1st neurons central processes nucleus proprius lamina I. IV. V. 2nd neurons cross to opposite side anterior white commissure lateral & anterior spinothalamic tract lateral funiculus runs up to brain stem3rd neurons VPLpostcentral gyrus, pos

14、terior part of paracentral lobule posterior limb of internal capsule thalamocortical tract 1. 軀干四肢淺感覺傳導(dǎo)路 The superficial sensory pathways of trunk and limbs dorsal roots Lissauers fasciculus asend 12 segments Spinal ganglia1neuron nucleus proprius Lamina, 2neuron Lateral spinothalamic tract anterior

15、 spinothalamic tract Spinal lemniscusVPL 3neurons Central thalamic radiationupdownSuperficial sensory pathways of trunk and limbspostcentral gyrus & posterior part of paracentral lobule nociceptornociceptorA nerveC nervespinothalamicpathwayto reticularformationreticular formationspinothalamicpathway

16、thalamussomato-sensorycortexImpulses transmitted to spinal cord by Myelinated A nerves: fast pain (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)*Lesion and Appearance(1) Interruption of

17、 pathways by lesions at anterior white commissure to causes Symmetrical 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)Spinothalam

18、ic damagespinothalamic pathwayLHSspinal cord injuryLoss of sense of:TouchPainWarmth/coldin right legBrown-Sequard Syndromereceptors skin mucosa sensory branches of trigeminal nerve peripheral processes trigeminal ganglion 1st neurons central processes spinal nucleus & pontine nucleus of trigeminal n

19、.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(dǎo)路 The superficial sensory pathways of head and face Trigemi

20、nal 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 face*Lesion and Appearance(1) Interruption of pathways by lesions at tri

21、geminal 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 part of postcentral gyrus(1)(2) Visual pathwaysOptic nerveOptic tractLat

22、eral geniculate nucleusOptic radiationOptic chiasmPrimary visual cortex1. 視覺傳導(dǎo)路 The visual pathwayreceptors rod & cone cells external layer of retinaperipheral processes bipolar cells1st neurons central processes ganglionic cells2nd neurons optic nerve optic chiasma optic tract 3rd neurons lateral g

23、eniculate body both banks of the calcarine sulcusposterior limb of internal capsule optic radiation middle layer of retinadecussation of fibers from nasal halves of retina innermost layer of retinaaxons optic disc visual area Visual pathwayVisual areaOptic nerveOptic chiasmaOptic tractLateral genicu

24、late bodyOptic radiation*Lesion and AppearanceInterruption of pathways by lesions in: 1. Optic nerve 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 fieldsABC2. 瞳孔對(duì)光反射

25、通路 The pathway of pupillary reflexespostganglionic fibersRetinaaxons 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 pupilspreganglion

26、ic fibers to formPretectal area E-W nucleusOccculomotor n.Ciliary ganglia Sphincter pupil muscle Pathway of pupillary reflexesLight 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 r

27、eflex1. 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 Appearance12visual centerlightpretectal areaE-W nucleusvisual pa

28、thwaylight 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 ganglionIV) Acoustic ( or auditory ) pathway聽覺傳導(dǎo)路 The vi

29、sual 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 neurons medial geniculate body both transverse temporal gyriposterior limb of intern

30、al capsule acoustic radiation cochlear nerveboth side fibers( decussed & undecussed fibers )acoustic centertrapezoid body lateral lemniscus Bipolar neuron of cochlear ganglion Cochlear nerveCochlear nucleiTrapezoid body Lateral lemniscus Medial geniculate body Acoustic radiation Transverse temporal

31、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. joining medial longitudinal fasciculus joining vestibulospinal tractVestibular nucleus) Equilibratory pathwayOcu

32、lomotornucleusTrochlearnucleusAbducentnucleusAccessorynucleusreceptors cristae ampullares, maculae of utricle and sacculebipolar cellsperipheral processes vestibular ganglion 1st neurons central processes vestibular nucleus2nd neurons vestibular nerve axons are grouped into five courses: joining med

33、ial longitudinal fasciculus fibers end in oculomotor, abducent, trochlear nuclei, and anterior horn cells of upper cervical cord joining vestibulospinal tract to anterior horn cells of spinal cord entering cerebellum via inferior cerebellar peduncle connecting with reticular formation of brain stem,

34、 vagus and glossopharyngeal nuclei connecting with temporal, parietal and frontal cortex of hemisphere 平衡覺傳導(dǎo)路 The equilibratory pathwayEquilibratory pathwayII.運(yùn)動(dòng)傳導(dǎo)路 Motor (descending) Pathway ( Including pyramidal and extrapyramidal ) It is concerned with voluntary movement of skeletal muscles. It i

35、s composed of two orders of neurons - upper and 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 Lower motor neurons (

36、1) Cranial motor nuclei of brain stem(2) Anterior horn motor cells of spinal cord The Corticospinal Tract1. 皮質(zhì)脊髓束 Corticospinal Tractupper motor neuron Superior, middle parts of precentral gyrus & Paracentral lobule skeletal muscles of trunk and limbs Effector posterior limb of internal capsule inte

37、rmediate 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 ) ( anterior funiculus ) anterior corticospinal tract smaller par

38、t of crossed fibers of tract Lower motor neuronAnterior horn motor cells of spinal cordspinal nerve Corticospinal tractDecussation of pyramid Lateral corticospinal tractAnterior corticospinal tract upper motor neuron Lower motor neuronCorticospinal Tract The Corticonuclear Tract2. 皮質(zhì)核束 Corticonuclea

39、r Tractupper motor neuron Pyramidal neurons in Inferior part of precentral gyrus skeletal muscles of head and neck Effector genu of internal capsule brain stem to bilateral oculomotor, trochlear, trigeminal motor, ambiguus, accessory nuclei and superior part of facial nucleus, Pyramidal tract Lower

40、motor neuron Cranial motor nucleicorresponding cranial nerves and to contralateral hypoglossal nucleus and inferior part of facial nucleusCorticonuclear tractOculomotor Nucleus Trochlear Nucleus Trigeminal Motor Nucleus Abducent NucleusSup. part of Facial NucleusInf. part of Facial NucleusAmbiguus N

41、ucleusAccessory Nucleus Hypoglossal NucleusCorticonuclear TractInfranuclear paralysis - Injury of unilateral facial nerve or hypoglossal nerve Paralysis of homolateral facial muscles and glossal muscles Supranuclear paralysis - Injury of unilateral corticonuclear tract Paralysis of contralateral glo

42、ssal muscles and facial muscles below palpebral fissureSupranuclear paralysisInfranuclear paralysisInfranuclear paralysis - Injury of unilateral ( left ) facial nerve Lesion for pyramidal system1. Uni-paralysis ( cerebral paralysis ) Motor Area 2. Alternate Paralysis Brain Stem (1) Alternating oculo

43、motor hemiplegia - Webers syndrome (2) Alternating 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 Paralysis5. Capsular Hemiple

44、giaAlternating HemiplegiaBrown-Sequard SyndromePyramidal systemPyramidal tractUpper motor neuronsInferior motor neuronseffectorsParalysisTonicityTendon reflexPathologic reflex (Babinski sign)Muscle atrophyspastic (hard)paralysis flaccid (soft) paralysis ( + )No( in short period ) ( )Yes ( 下神經(jīng)元不斷發(fā)放沖動(dòng)

45、 保證肌肉的營(yíng)養(yǎng)代謝 )Interruption of reflex arc 錐體束對(duì)下神經(jīng)元 的抑制性影響消失 disappearMotor areaLesion for pyramidal systemPeripheral nerves Somatic motor F.Signs of Upper Motor Neuron (UMN)and Lower Motor Neuron (LMN) LesionsSignUMN LesionsLMN Lesions ParalysisHard paralysisFlaccid paralysisToneIncreasedDecreasedTendo

46、n reflexDisappearBabinski signYesNoAtrophyNo*Yes*Mild atrophy may develop due to disuse.Increased) 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(fù)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 ext