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1、Nervous TissueWhat a beautiful world!Nervous Tissueneurones：neuroglia：Receive stimuli, Conduct electrical impulseEndocrineSupporting cellsOutlineNeuron: 章心怡章心怡 Synapse：周佩：周佩Neuroglia：徐伊琳：徐伊琳 Nerve fiber：何紫仪：何紫仪Nerve Ending：张子琛：张子琛Basic Neurone typesBipolar neuronePseudo-unipolar neuroneMultipolar ne
2、uronen soma(cell body)：variation in size and shape; metabolic centern axon: single, arise from the Axon hillock terminate on the other neurons or effector organs ( nerve ending) generate and conduct action potencial(electrical impulse)n dendrite: one or more, highly branched(dendritic spine), taperi
3、ng processes major sites of information inputThe basic structure of NeuroneThe basic structure of Neurone1、soma (cell body)：membrane：excitable，containing ion channel and neurotransmitter receptorsneucleus：pale stained, centrally located, nucleolus prominentcytoplasm(perikaryon)：Nissle body, Neurofib
4、ril, etc Nissl body LM: clumps of highly basophilic cytoplasm material EM: abundant RER and free ribosomes Functions：protein systhesis (enzymes, structual proteins) Neurofibril LM: argyrophilic, interlaced into network present in peikaryon, dentrites and axon EM: microfilaments and microtubules Fuct
5、ions: maintain the cell shape, axonal transport, Found in perikaryon and dentrites but is not present in axon hillock or axonAxonal transportAnterograde Retrograde ( eg:neurotransmitter)( eg:some viruses infection)NeurondendriteNissle bodyNeurofibrilNode of RanvieroligodendrocyteCNSPNSSchwann cellMy
6、elin sheathMyelin sheathTerminal endAxon hillockMotor neurons of spinal cord the sites of intercommunication between neurons or between neurons and effector cells two types of synapse: chemical synapse: conducted by neurotransmitter， one way conduction electrical synapse: gap junction, conducted by
7、ion, one way or both ways conduction synapsesynapse Axodendritic: “standard” Axosomatic: Axoaxonic synapses AxospinicThe most common sites for synapsesThe most common sites for synapsesdendriteaxonaxosomaticAxodendriticaxospinicaxoaxonicchemical synapseLM：synaptic knob （presynaptic swellings）EM pre-
8、synaptic elementSynaptic vesicles(NeuroTransmitter)Pre-synaptic membranemitochondriaSynaptic cleft: enzymes to inactivated NT between successive action potencialPost-synaptic elementPost-synaptic membraneReceports of NTIonic channelssynaptic knobSynaptic vesiclespresynaptic membraneSynaptic cleftpos
9、tsynaptic membraneaxosomaticAxodendriticaxospinicsynapsesynapseNeuroglialNeuroglialn more numerous than neuronesn highly branched cellsn providing both mechanical and metabolic support of neurones AstrocytesOligodendrocytesMicrogliaEpendymal cellsSchwann cellSatellite cell (capusule cell)CNS:PNS:Ner
10、vous systemCentral Nervous System:Peripheral Nervous Systemspinal cordbrainnervegangliaAstrocyte: star shaped; have prolific, long, highly branched processes perivascular feet (terminal expansions of processes)Fibrous astrocytes：in white matter, less processes, more microfilamentsProtoplasmic astroc
11、ytes：in grey matter, more processes, less microfilamentsFunctions: protection (blood brain barrier formation) repair tissue damage (scar formation) AstrocytesFibrous astrocytesProtoplasmic astrocytescapilaryPerivascular feetFibrous astrocytesProtoplasmic astrocytesblood brain barrierFuctions：maintai
12、n the enviroment of the brain in a steady statenthe endothelial cells of capillaries (tight junctions, limited methods of transcellular transport)n intact basement membranen perivascular feet of the astrocytesSmall lipid-soluble molecules cross the barrier easily (eg. diamorphine)Hydrophilic molecul
13、es rely on specific transporter systems Blood brain barrierEpithelial cellTight junctionBasement membranePerivascular feet of astrocytepericyteBrain ischaemia, brain tumors, haemorrhage or infections may break down the blood brain barrieroligodendrocyte l small number of short, branched processesl a
14、re responsible for myelination of axons in the CNS microglias a member of mononuclear phagocytic system ependymal cellsl form the simple cuboidal epithelium lining of the ventricles and spinal canall most of them have cilia on their surfacesl contribute the flow of cerebrospinal fluid Schwann cell l
15、 are responsible for the myelination of axons in the PNSn Satellite cell (capsular cell） surround the nerve cell bodies in ganglia Neuroglia in PNS:Neuroglia in PNS: Nerve fibers Nerve fibersaxonsneurogliaCNS：oligodentrocytesPNS：Schwann cells+Myelinated nerve fibersNon-myelinated nerve fibersDepend
16、on the myelinationMyelin sheath myelinated nerve fiber in PNSAxons are wrapped by a variable number of concentric layers of the Schwann cell plasma membrane forming myelin sheath plasma membrane: myelin (phospholipid) and proteinEM: many concentric layers of plasma membraneinsulationNode of RanvierM
17、yelin sheathSchwann cell nucleus AxonIncisure of myelinProtein network(Schmidt-Lantermann incisure)Myelination of nerve fibers in PNSMesaxonMyelinated nerve fiberMyelinated nerve fiber 2. 2.Myelinated nerve fiber in the CNSOligodendrocytes are responsible for the myelinationAxonoligodentrocyteMyelin
18、 sheathNode of Ranvier Non-myelinated nerve fiber1、PNS axons are embedded into the cytoplasma of the Schwann cells.2、CNS naked axons Schwann cellAxonNon-myelinated nerve fiberFunction of nerver fiber：condution of nerve impulse (action potencial)Myelinated nerve fiber：saltatory conduction, much faste
19、rNon-myelinated nerve fiber：continuous conductionContinuous conductionSaltatory conductionWhat will happen if demyelination occur？n Multiple-sclerosis: demyelination occurs in the CNS nGuillain-Barre syndrome demyelination occurs in the peripheral nerves Nerve endingsFree nerve ending ：responsible f
20、or cutaneous pain and temperature Tactile corpuscle: light discriminartory touchLamellar corpuscle: pressure, coarse touch, vibration and tension Muscle spindle: proprioceptorTerminal ends of nerve fiber （+） non-nervous tissue sensory nerve endingsEncapsulated nerve ending:Free nerve endings Tactile
21、 corpuscle Meissners corpuscle located in dermal papillae of skin responsible for light discriminartory touchLamellar corpuscle Pacinian corpuscle can be found in the deeper layers of the skin, ligaments, mesenteries, some viscera, some erogenous areas involved in pressure, coarse touch, vibration a
22、nd tensionMuscle spindle within skeletal muscles regulation of muscle tone via spinal stretch reflexmotor nerve endingn Somatic motor nerve ending：motor end plate （neuromuscular junction） synapse between motor neuron and skeletal muscle fiber control the contraction of skeletal muscle fibersnVisceral motor nerve ending: control the contraction of cardiac muscle fibers, smooth muscle fibers and the secretion of glandsMotor end plateMotor end plate
