组胚学课件：Nervous tissue

1、Nervous tissue神经组织,20140415,Overview -Components: nerve cell: neuron Glial cell: neuroglia -Function: Neurons : receive the stimulation, conduct the nerve impulse Glial cell: support, protect and insulate, nourish neurons,Neuron,The structural and functional cellular unit,LM: -cell body: spherical,

2、pyramidal fusiform or stellate in shape, 5um-150um -dendrite （树突） -axon （轴突）,structure of neuron cell body: -cell membrane: unit membrane-irritability, receive stimuli, initiate and conduct nerve impulse membrane proteins - ions channel and receptor,cell nucleus: large and round centrally- located l

3、ess heterochromatin pale stained, with a clear nucleolus,-cytoplasm: perikaryon a.Nissl body (尼氏体): LM: basophilic granule-liked structure EM: parallelly-arranged RER and free ribosome Function: synthesis proteins structural protein enzymes of neurotransmitters,b.Neurofibril(神经原纤维): silver impregnat

4、ion methods (silver preparation) thread-liked dark brown color structure to form a network.,EM: neurofilament: 10 nm in diameter microtubule: 25 nm in diameter Function: supporting involving in intracellular transportation,c. other organelle Golgi apparatus mitochondria pigment, dendrite(树突): many,

5、short and more branches structure similar to cell body dendritic spine (synapse) and spine apparatus (structure formed by 2-3 layers SER) Function: receive the information, axon(轴突): thin, less branch axon hillock(轴丘): the beginning without Nissl body axolemma axoplasm -Function: initiate an impulse

6、 and conduct the impulse,* axonal transports slow anterograde cytoskeletal protein: microtubule, microfilament and neurofilament (0.1-0.4 mm/d) fast anterograde synaptic vesicles, enzymes and proteins( 100-400 mm/d) fast retrograde products of metabolism, intaking materials including protein or neur

7、otropic factors (100-300 mm/d),3) classification: -According to the number of processes multipolar neuron bipolar neuron pseudounipolar neuron,-According to length of axon Golgi type I neuron long axon and large Golgi type II neuron short axon,-According to function sensory neuron motor neuron inter

8、neuron,-According to the neurotransmitter or neuromodulator cholinergic neuron aminergic neuron peptidergic neuron aminoacidergic neuron,Synapse (突触),-definition: the junctions between neurons or neuron and non-nerve cells -classification: chemical synapse: taking neurotransmitter as communicating m

9、edium electrical synapse: gap junction,-structure of chemical synapse: LM in silver preparation on the surface of dendrites and cell body button-liked structures (synaptic button),EM 1)presynaptic element: axonal terminal presynaptic membrane synapse vesicle: -round or flattened, 40-60nm -clear or w

10、ith electron dense core 2)synaptic space: 15-30nm 3)postsynaptic element: postsynaptic membrane receptors,Glial cell (neuroglia)神经胶质细胞,Glial cell in CNS Astrocyte (星形胶质细胞) fibrous astrocyte protoplasmic astrocyte Oligodendrocyte (少突胶质细胞) Microglia (小胶质细胞) Ependymal cell (室管膜细胞),fibrous astrocytes -w

11、hite matter, have long, thin and smooth processes -more glial filament- glial fibrillary acidic protein, GFAP protoplasmic astrocytes -gray matter, short, thick processes with more branch -less glial filament,Oligodendrocyte(少突胶质细胞): smaller, fewer process form myelin-sheath of NF in CNS,Microglia(小

12、胶质细胞): smallest, elongate shape or ovoid, with a small dark irregular N phagocytosis- mononuclear phagocyte system？,Ependymal cell (室管膜细胞): simple cuboidal or columnar epi apical: microvilli and cilia basal: long processes -Distribution: ventricle of brain and central canal of spinal cord,Glial cell

13、 in PNS a.Schwann cell: form myelin-sheath in PNS b. Satellite cell (capsular cell): surrounding the Neuron in ganglion,Nerve fiber and Nerve formed by axon and glial cell classification myelinated nerve fiber (有髓神经纤维) unmyelinated nerve fiber (无髓神经纤维),LM: Axon myelin-sheath: net-liked OsO4(osmium t

14、etroxide) fixation and stain Schmidt-Lantermann incisure neurilemma: cell membrane +basement membrane Schwann cells (PNS) Oligodendrocyte (CNS),Myelinated nerve fiber,Ranvier node (郎飞结): narrow part, no myelin-sheath- saltatory conduction Internode segment (结间体): the segment of NF between two Ranvie

15、r nodes,MNF in CNS similar to that of PNS oligodendrocyte one oligodendrocyte can envelop many axons no incisure and basement membrane,Unmyelinated nerve fiber,thin axon and Schwann cell connect end to end no myelin-sheath and Ranvier node one Schwann cell envelops more axons naked axon (CNS),Nerve

16、-Nerve fiber gets together Epineurium perineurium endoneurium,Blood brain barrier (血脑屏障),Endothelial cell of continuous Cap. basement membrane Foot processes of astrocytes,Nerve Ending,1.Free nerve ending -function: feel cold, hot, pain and slight touch 2.Encapsulated N ending -have CT capsule Meissners corpuscle (tactile)触觉小体: touch receptor Pacin