系统解剖学英文版教学课件：NS introduction spinal cord

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1、The Nervous SystemThe nervous system Chapter one introductionI.Division of the nervous system central part:brain and spinal cord peripheral part:cranial,spinal and visceral(autonomic nervous system)nerves According to distribution in PNS:Somatic nerves:skin,mucus,skeletal muscle and jointsAutonomic(

2、visecral)nerves:smooth muscle,cardiac muscle,blood vessels,glandsII.Composition of the nervous system nerve cells(neurons)and glial cells(neuroglia)(I)Neurons independent structural and functional units of the nervous sytem.1.Structure:consists of cell body and processes(an axon and one or more dend

3、rites)Cell body(soma):Nissle body(endoplasmic reticulum with ribosomes)Axon:a single,end in terminal boutonDendrite:dendrite spine(gemmulus)Nissle bodyAxonAxon terminalDendrite2.Myelinated and nonmyelinated nerve fibers Myelinated nerve fibers:The nerve fibers(mainly axon)enveloped by myelin sheath

4、which is formed by Schwann cell in the PNS and oligodendrocyte in the CNS.Unmyelinated nerve fibers:The nerve fibers not enveloped by myelin sheath.3.Synapses:One neuron contacts with another neuron to form synapse.Chemical synapse:presynaptic membrane,postsynaptic membrane and synaptic cleft.The ax

5、odendritic synapse is most common,and the axosomatic is quite common.A special synapse is the neuromuscular junction or motor end plate.Electrical synapseSynapse under electronic microscope4.Classification:According to the number of the processes:a.pseudounipolar neuron b.bipolar neuron c.multipolar

6、 neuron According to function of the neuron:a.sensory neuron b.motor neuron c.interneuron Others,Golgi I and II,et al.(II)Neuroglia(glial cells)Large neuroglia:Astrocyte:between neurons and capillaries,form“scar tissue”Oligodendrocyte:form myelinSchwann cell(in PNS):form myelinEpendymal cell:line ca

7、vities in the brain Small neuroglia:microglia(phagocytic cells)Glial scarcavityIII.The reflex and reflex arch 1.Conception of the reflex 2.Composition of the reflex arch sensory receptors,afferent neurons,interneurons,efferent neurons effectors Reflex archIV.Terminology 1.Gray matter and white matte

8、r,cortex and medullaGray matter:Groups of nerve cell bodies and their dendrites in the CNS are termed gray matter.White matter:Bundles of nerve fibres in the CNS are termed white matter.White matterGray matterNucleusMedullaCortex2.Nucleus and ganglionNucleus:Nerve cells with the same shape and funct

9、ion in the CNS are grouped together to form nucleus.Ganglion:Nerve cells with the same shape and function in the PNS are grouped together to form ganglion.Nucleus3.Fasciculus,funiculus and nervesFasciculus:A group of nerve fibers with common origins,destinations and functions in the CNS is termed fa

10、sciculus.Funiculus:A group of nerve fibers with different origins,destinations and functions in the CNS is termed funiculus.Nerves:Nerve fibers are grouped together in the PNS are termed nerves.Chapter 2 The central nervous system Section one spinal cord I.Location in the vertebral canal and between

11、 the foramen magnum and the lower border of the first lumbar vertebra(L3 in the fetus)II.External features six sulci,two enlargements and one filum terminale,thirty-one segments.1.Six sulci:anterior median fissure and posterior median sulcus,two anterolateral sulci,two posterior lateral sulci2.Two e

12、nlargements:cervical enlargement(C4-T1)and lumbosacral enlargement(L2-S3)3.One filum terminale:formed by pia mater4.Conus medullaris:lower end5.Cauda equina:spinal roots around filum terminal6.Thirty-one segments:C1-8,T1-12,L1-5,S1-5,Co1 Spinal cord segments Vertebral bodiesC1-4 C1-4C5-T4 C4-T3T5-8

13、T3-6T9-12 T6-9L1-5 T10-12S1-Co1 L1Relationship between spinal cord and vertebral bodies in adultsLumbar puncture for CSF,such as meningitis L1III.Internal structure consists of the grey matter,white matter and central canal.(I)Gray matter anterior horn posterior horn lateral horn(intermediate zone)(

14、一)Gray matter 1.Anterior horn:large neuron-motor neuron:innervates the extrafusal fibers of the skeletal musclesmall neuron-motor neuron:innervates the intrafusal fibers of the skeletal muscle Renshaw cell:inhibite-motor neuron Medial group and lateral group of anterior horn2.Posterior horn:Nucleus

15、posteromarginalis,Substantia gelatinossa(of Rolando),Nucleus proprius:send spinothalamic tracts Nucleus thoracicus(nucleus dorsalis of Clarke):send posterior spinocerebellar tracts3.Lateral horn(intermediate zone)intermediolateral nucleus:extends from C8-L2 or L3.It is the center of the sympathetic

16、system.give off sympathetic preganglionic fibers sacral parasympathetic nucleus:extends from S2-S4.It is one center of the parasympathetic system.intermediomedial nucleus:send spinocerebellar tracts 4 The laminae Based on the neuronal size,shape,cytological features and density within the grey matte

17、r,the grey matter is divided into ten laminae(Rexeds laminae)Lamina I:thin marginal layer Lamina II:substantia gelatinosa Lamina III and IV:nucleus propriusLamina V:respond to noxious and visceral afferent stilumi Lamina VI:respond to mechanical siganls from joints and skinLamina VII:dorsal nucleus

18、and intermediolateral nucleusLamina VIII and IX:motor neurons in the anterior horn Lamina X:around the central canal(II)White matter 1 Long ascending tracts:carry sensory impulses Gracile fasciculus and cuneate fasciculus location:in the posterior funiculus function:conduct the ipsilateral fine touc

19、h,two-point discrimination,proprioception(deep sense)Lateral spinothalamic tract location:in the posterolateral periphery of the lateral funiculus function:conduct the contralateral pain and temperature sense below one or two segments of the original level Anterior spinothalamic tract location:in th

20、e anterior funiculus function:conduct the contralateral crude touch below one or two segments of the original level Anterior and posterior spinocerebellar tracts:conveys the subconscious proprioceptive sense to the cerebellum 2.Long descending tracts:carry motor impulses Corticospinal tract a.latera

21、l corticospinal tract location:in the lateral funiculus function:innervate the muscle of the extremities by influencing the spinal cord b.anterior corticospinal tract location:in the anterior funiculus function:innervate the muscle of the neck and trunk by influencing the spinal cord Tectospinal tra

22、ct:regulates the influence of optical reflexes on the muscle of the neck Rubrospinal tract:helps flexor motor neurons Vestibulospinal tract:increases the extensor muscle tone Reticulospinal tract:play a role in moderation of the muscle tone.3 Short ascending and descending tractsFasciculus proprius:

23、take part in the intrinsic reflex mechanism of the spinal cordDorsolateral fasciculus(of Lissauer):consists of fine myelinated and unmyelinated posterior root fibers and relates to transmit pain and temperature sense.IV.Functions of spinal cord1.reflex2.conduction Knee jerk flexVII.In the clinical Brown-Sequard syndromeIpsilateral lower motor neuron paralysisIpsilateral loss of deep sensation,two-points discrimination below the lesionContralateral loss of pain and temperature below 1 or 2 segments at the lesion level