Nervous Tissue

Prof.Prof. ZhouZhou LiLi Dept.Dept. ofof HistologyHistology andand EmbryologyEmbryology Organization:Organization: neuronsneurons (nerve(nerve cells)cells) neuroglialneuroglial cellscells Function:Function: Ⅰ Neurons 1.1. structurestructure ofof neuronneuron somasoma neuriteneurite a.a. dendritedendrite b.b. axonaxon 1.11.1 somasoma (1)(1) nucleusnucleus LocatedLocated inin thethe centercenter ofof soma,soma, largelarge andand palepale--stainingstaining nucleusnucleus ProminentProminent nucleolusnucleolus (2)(2) cytoplasmcytoplasm (perikaryon)(perikaryon) a.a. NisslNissl bodybody b.b. neurofibrilneurofibril

‹NisslNissl’’ss bodiesbodies LM:LM: basophilicbasophilic massmass oror granulesgranules Nissl’s Body (TEM) EMEM:: RERRER,, freefree RbRb FunctionFunction:: producingproducing thethe proteinprotein ofof neuronneuron structurestructure andand enzymeenzyme producingproducing thethe neurotransmitterneurotransmitter NeurofibrilNeurofibril „thethe structurestructure ‹ LM:LM: ‹ EM:EM: NeurofilamentNeurofilament micmicrotubulerotubule „FunctionFunction cytoskeleton,cytoskeleton, toto participateparticipate inin substancesubstance transporttransport LipofuscinLipofuscin (3)(3) CellCell membranemembrane excitableexcitable membranemembrane ,, receivingreceiving stimutation,stimutation, fromingfroming andand conductingconducting nervenerve impulesimpules neurite: 1.2 Dendrite ‹ dendritic spine ‹ spine apparatus ‹ Function: 1.3 Axon ‹ axon hillock, axon terminal, axolemma ‹ Axoplasm: microfilament, microtubules, neurofilament, mitochondria, SER and vesicles in it ‹ function: conducting impules and axonalaxonal transporttransport 2. Classification of neuron: 2.12.1 ClassificationClassification accordingaccording toto numbersnumbers ofof neuritesneurites (1)(1) multipolarmultipolar neuronneuron (2)(2) bipolarbipolar neuronneuron (3)(3) PseudounipolarPseudounipolar neuronneuron peripheralperipheral processprocess centralcentral processprocess 2.2 Classification according to their the functions (1)(1) sensorysensory neuronneuron ：： (2)(2) motormotor neuronneuron：： (3)(3) interneuroninterneuron：： 2.3 Classification according to the neurotransmitter and neuromodulator (1) cholinergic neuron: acetylcholine (Ach), (2) aminergic neuron: norepinephrine (NA), dopamine (DA), 5-HT, (3) peptidergic neuron: substance P, enkephaline (4) aminoacidergic neuron: GABA, glutamic acid Ⅱ Synapse

„ OneOne kindkind ofof specializedspecialized cellcell junction,junction, oror thethe contactcontact ofof oneone neuronneuron withwith anotheranother neuronneuron oror oneone neuronneuron withwith aa effectoreffector cellscells (gland(gland oror musclemuscle cells)cells) „ junctionjunction modemode :: ‹axoaxo--dendriticdendritic synapsesynapse (most(most synapse)synapse) ‹axoaxo--somaticsomatic synapsesynapse (most(most synapse)synapse) „ classificationclassification ofof synapse:synapse: ‹cchemicalhemical synapsesynapse ‹electricalelectrical synapsesynapse (gap(gap junction)junction) The type of synapse Chemical Synapse The stucture of synapse LM: synaptic knob EM: ‹ presynaptic element  presynaptic membrane  synaptic vesicles (*synapsinⅠ)  mitochondria , SER, microfilament and microtubule ‹ synaptic cleft ‹ postsynaptic element  postsynaptic membrane  Function: excitatory synapse, inhibitory synapse Synaptic knob Synapse (TEM) Ⅲ Neuroglial cells (glial cell) 1.1. glialglial cellscells ofof centralcentral nervenerve systemsystem

‹aastrocytestrocyte::

‹oligodendrocyteoligodendrocyte

‹microgliamicroglia

‹ependymalependymal cellcell 2.2. glialglial cellscells ofof peripheralperipheral nervenerve systemsystem

‹schwannschwann cellcell

‹satellitesatellite cellcell Neuroglial cell (1) Astrocytes „TheThe morphologicmorphologic structure:structure: fibrousfibrous astrocyteastrocyte ((thethe mostmost inin whitewhite matter),matter), protoplasmicprotoplasmic astrocyteastrocyte (the(the mostmost inin graygray matter),matter), glialglial filamentfilament glialglial fibrillaryfibrillary acidicacidic protein,protein, GFAPGFAP astrocyte (LM) end feet, glia limitans Function: ① to form blood-brain barrier ② to produce the neurotrophic factors (NGF) ③to repair never tissue after the damage blood brain barrier(BBB):

„ **continuouscontinuous capillarycapillary,, tighttight junctionjunction „ *basement*basement membranemembrane „ **neuroglialneuroglial membranemembrane (2) oligodendrocyte

„ thethe morphologicmorphologic structure:structure: „ function:function: formingforming myelinmyelin sheathsheath ofof CNSCNS (3) microglia „ The morphologic structure: „ function: macrophagic activity, derived from monocyte of blood (4) ependymal cells „ the distribution: lining cavities of central nervous system „ the structure: „ function: transport Microglial Ependymal cells (2) glial cells of peripheral nerve system

(1) schwannschwann cellcell :: toto repairrepair nevernever tissuetissue afterafter thethe damagedamage producingproducing NGFNGF ((2)2) satellitesatellite cell:cell: Ⅳ Nerve fiber and peripheral nerve 1.1. nervenerve fiberfiber beingbeing composedcomposed ofof longlong axonaxon oror dendritedendrite ofof neuronneuron envelopedenveloped byby glialglial cellscells 1.11.1 myelinatedmyelinated nervenerve fiberfiber (1)(1) myelinatedmyelinated nervenerve fiberfiber ofof PNSPNS thethe structure:structure: RanvierRanvier node,node, internodeinternode,, Myelinated nerve fiber (LM ) myelinated nerve fiber (TEM) „ FormationFormation ofof myelinmyelin sheathsheath ofof PNSPNS：： incisureincisure ofof myelinmyelin Incisure of myelin 1.2 Unmyelinated nerve fiber 2.2. PPeripheraleripheral NerveNerve

„EpineuriumEpineurium „PerineuriumPerineurium „EndoneuriumEndoneurium Ⅴ Nerve ending 1.1. sensorysensory nervenerve endingending receptorreceptor (1)(1) freefree nervenerve endingending (2)(2) encapsulatedencapsulated nervenerve endingending tactiletactile corpusclecorpuscle lamellarlamellar corpusclecorpuscle musclemuscle spindlespindle 2.2. motormotor nervenerve endingending effectoreffector Free nerve ending Tactile corpuscle Lamellar corpuscle (1)(1) somaticsomatic motormotor nervenerve endingending motormotor endend plateplate LMLM:: EMEM:: Motor end plate (SEM) Motor end plate(TEM) muscle spindle Muscle spindle Visceral motor nerve ending

„ varicosityvaricosity