神經(jīng)生物學--神經(jīng)細胞

1、神經(jīng)生物學講稿之三　　　　　神經(jīng)細胞,一　大腦基本結構二　神經(jīng)細胞三 神經(jīng)膠質細胞,2024/4/2,中山大學生命科學學院 項輝,2,一　大腦的結構,Fissures (deep grooves) divide the cerebrum into lobesSurface lobes of the cerebrumFrontal lobeParietal lobeOccipital lobeTemporal lo

2、be,2024/4/2,中山大學生命科學學院 項輝,3,人的大腦(Brain)包括左、右兩個半球及連接兩個半球的部分。大腦半球被覆灰質，稱大腦皮質，其深部為白質，或稱為髓質。大腦兩半球間由巨束纖維（胼胝體，corpus callosum）相連。 腦主要包括大腦、間腦、小腦、中腦、腦橋及延髓等六個部分。,2024/4/2,中山大學生命科學學院 項輝,4,,,2024/4/2,中山大學生命科學學院 項輝,5,Grey mattern

3、euron cell bodies or soma perikaryons protoplasmic astrogliaWhite matternerve cell processes axons and dendritesoligodendroglia and fibrous astroglia,2024/4/2,中山大學生命科學學院 項輝,6,Cerebral hemispheres　　　　DiencephalonBr

4、ain stem　　　　　　　　　Cerebellum,2024/4/2,中山大學生命科學學院 項輝,7,2024/4/2,中山大學生命科學學院 項輝,8,Ventricles and Location of the Cerebrospinal Fluid,2024/4/2,中山大學生命科學學院 項輝,9,What additional functions do brain cells have?,Neurons: Need to c

5、ommunicate with one anotherNeed to communicate across large distancesNeed to transport proteins over long distances within the neuronGlia Astrocytes: create and maintain barriers, provide physical support and “clean

6、-up” debrisMicroglia: “clean up” and inglamatory responseOligodendrocytes: Support for axons and myleination,2024/4/2,中山大學生命科學學院 項輝,10,二　神經(jīng)細胞之神經(jīng)元,2024/4/2,中山大學生命科學學院 項輝,11,What specializations have evolved that provi

7、de brain cells with the ability to perform these functions?,2024/4/2,中山大學生命科學學院 項輝,12,Physical Specializations for Neurons,,Axon hilock,2024/4/2,中山大學生命科學學院 項輝,13,Specializations for Neurons,Communication between neurons

8、DendritesAxons/Synaptic BoutonsNeurotransmitterReceptorsMechanisms to maintain ionic gradients,2024/4/2,中山大學生命科學學院 項輝,14,What do all these cells have in common?,,,,,,,,,,,,,,,,2024/4/2,中山大學生命科學學院 項輝,15,,,2024/4/2,中山大

9、學生命科學學院 項輝,16,Dendrites,Size and shape of the dendritic tree are specialized depending on the type of neuron,2024/4/2,中山大學生命科學學院 項輝,17,Dendrites,The extensive branching of dendrites and dendritic spines provide large sur

10、face area for input from other neurons.,2024/4/2,中山大學生命科學學院 項輝,18,Dendrites,,,Dendritic Tree,,Axon,Can receive information from more than one neuron, allowing convergence and integration of signals from multiple areas.,2

11、024/4/2,中山大學生命科學學院 項輝,19,Dendrites,Dendrites receive signals through the synapse. The post-synaptic membrane is located on the dendrite.In this area there are receptors for specific neurotransmitters.The receptors can

12、 cause an excitatory or an inhibitory response, depending on the receptor type.The large area allows for many inputs, from multiple neurons.,What structures/mechanisms allow neurons to send communication signals?,2024/4

13、/2,中山大學生命科學學院 項輝,21,The Axon!,,2024/4/2,中山大學生命科學學院 項輝,22,Axons,Axons vary in diameter and length, allowing for communication across both small and large distances. Variations in diameter alter the kinetics of the acti

14、on potential.,2024/4/2,中山大學生命科學學院 項輝,23,Axons,Each neuron has one axon that extends from the soma via the axon hillock.The axon hillock is the site of initiation for the action potential.,2024/4/2,中山大學生命科學學院 項輝,24,Axon

15、 Hillock = 2,,2024/4/2,中山大學生命科學學院 項輝,25,Axons,The axon is surrounded by a myelin sheath that is formed by either Schwann Cells (PNS) or Oligodendrocytes (CNS).Segments of the axon remain exposed.These segments, Nodes o

16、f Ranvier, contain high concentrations of ion channels.,2024/4/2,中山大學生命科學學院 項輝,26,2024/4/2,中山大學生命科學學院 項輝,27,Node of Ranvier,,2024/4/2,中山大學生命科學學院 項輝,28,Channels are nested within the Node of Ranvier,Sodium (Na+) voltage g

17、ated channelsPotassium (K+) voltage and leak channelsNa/K pumpThese channels maintain the membrane potential and provide the mechanism for action potential generation.,2024/4/2,中山大學生命科學學院 項輝,29,Microtubules serve two

18、main purposesSupport structureMechanism for transport within the axon.,Microtubules,2024/4/2,中山大學生命科學學院 項輝,30,,Retrograde and Anterograde Transport Depend on Microtubules and Motor Proteins,2024/4/2,中山大學生命科學學院 項輝,31,A

19、neuron has many of the same "organelles" Nucleus - Contains genetic material including information for cell development and synthesis of proteins necessary for cell maintenance and survival. Nucleolus - Prod

20、uces ribosomes necessary for translation of genetic information into proteins Nissle Bodies - groups of ribosomes Endoplasmic reticulum (ER) - system of tubes for transport of materials within cytoplasm. Can have ribo

21、somes (rough ER) or no ribosomes (smooth ER). Golgi Apparatus - important in packaging peptides and proteins (including neurotransmitters) into vesicles. Microfilaments/Neurotubules - system of transport Mitochondria

22、 - Produce energy to fuel cellular activities.,2024/4/2,中山大學生命科學學院 項輝,32,There are several differences between axons and dendrites:,AxonsTake information away from the cell body Smooth Surface Generally only 1 axon

23、 per cell No ribosomes Can have myelin Branch further from the cell body,Dendrites Bring information to the cell body Rough Surface (dendritic spines) Usually many dendrites per cell Have ribosomes, mito

24、chondria No myelin insulation Branch near the cell body,2024/4/2,中山大學生命科學學院 項輝,33,三　神經(jīng)細胞之神經(jīng)膠質細胞,Make contact with neuronsSurround synapsesIntimate contact with blood vessels and other astrocytesMop up inactive neur

25、otransmittersRegulate nerve impulsesForm blood brain barrierGuide migrating neurons during brain development,2024/4/2,中山大學生命科學學院 項輝,34,The types of Neuroglia,2024/4/2,中山大學生命科學學院 項輝,35,,2024/4/2,中山大學生命科學學院 項輝,36,,2024/

26、4/2,中山大學生命科學學院 項輝,37,Astrocytes,Form “scafolding” for neurons to attach to throughout the gray matter.Absorb excess NT near the synaptic cleft.Provide nutrient support to neurons.Seal the blood brain barrier,2024/4/2,

27、中山大學生命科學學院 項輝,38,Blood Brain Barrier-BBB,2024/4/2,中山大學生命科學學院 項輝,39,Microglia,1. Phagocytotic cells that absorb dead or dying neurons.2. Part of immune response,2024/4/2,中山大學生命科學學院 項輝,40,Neuroglia vs. Neurons,Neuroglia

28、divide.Neurons do not.Most brain tumors are “gliomas.”Most brain tumors involve the neuroglia cells, not the neurons.Consider the role of cell division in cancer!,2024/4/2,中山大學生命科學學院 項輝,41,Glia Tell Neurons to Build

29、Synapses,Ｓｃｉｅｎｃｅ,　2001,291∶569～570ａ與膠質細胞共同生長的神經(jīng)元突觸的活躍程度是獨自生長的神經(jīng)元的10倍。膠質細胞在某種程度上放大了神經(jīng)元發(fā)出的信號或者提高了神經(jīng)元接受信號的敏感度。,2024/4/2,中山大學生命科學學院 項輝,42,神經(jīng)膠質細胞可促進腦部信息傳遞,大鼠的神經(jīng)膠質細胞在受到適當刺激后，會釋放出自己的信息傳導物質。這些物質同神經(jīng)元相互作用，使他們更易對其他神經(jīng)元發(fā)出的信號進行反應。尋

30、找抑郁癥等疾病的治療方法時，不再專注于神經(jīng)細胞的興奮，可考慮通過膠質細胞促進神經(jīng)元間信息傳遞的方法。Nature neuroscience 2005 8(8):1078,2024/4/2,中山大學生命科學學院 項輝,43,神經(jīng)元放電串中所含信息的編碼理論和分析方法,神經(jīng)系統(tǒng)對來自內、外環(huán)境的信息進行轉化、編碼、整合、儲存,引起感覺并使相應的效應器作出反應。整個過程主要是通過動作電位在神經(jīng)纖維上的傳導和突觸處化學傳遞實現(xiàn)的。現(xiàn)公認動

31、作電位串內蘊含豐富的信息。對神經(jīng)元放電串及其所蘊含信息的研究成為神經(jīng)科學和信息科學的一個重要領域。各種編碼理論和分析方法也就應運而生。,2024/4/2,中山大學生命科學學院 項輝,44,,,2024/4/2,中山大學生命科學學院 項輝,45,神經(jīng)元放電串的常用分析方法,(一)間隔分布分析　間隔直方圖(二)相關性分析(時間域分析)(三)頻譜分析(頻率域分析)　(四)混沌和分形　(五)模式分析　對神經(jīng)元放電串及其蘊含信息的研究