神经元和神经胶质细胞-胶质细胞-Composition-of-Nervous-Tissu课件

1、Neuron :Supporting cells :CNS : neuroglia (glia)PNS : Schwann cells and satellite cellsFunctions :physical supportelectrical insulationmetabolic exchangeblood-brain barrierComposition of Nervous TissueNeuron :Composition of NervousTypes and Functions of GliaName of Glial CellFunctionAstrocyte (Astro

2、glia)Star-shaped cells that provide physical and nutritional support for neurons: 1) clean up braindebris; 2) transport nutrients to neurons; 3) hold neurons in place; 4) digest parts of dead neurons; 5) regulate content of extracellular space MicrogliaLike astrocytes, microglia digest parts of dead

3、 neurons.Oligo-dendrogliaProvide the insulation (myelin) to neurons in the central nervous system.Satellite CellsPhysical support to neurons in the peripheral nervous system.Schwann CellsProvide the insulation (myelin) to neurons in the peripheral nervous system.Types and Functions of GliaNamNeurogl

4、ia in the CNSNeuroglia in the CNSAble to replicate!Importance in nervous system function is VASTLY underestimated!Evidence is mounting: Nurturing roleSignaling role (Memory?)InflammationPainMany more to come!Neuroglia: Distinguishing FeaturesAble to replicate!Neuroglia: Presence of tight junctions b

5、etween the endothelial cellsOne of the notable features of endothelial cells in comparison to other cell is the lack of pinocytic vesiclesSelective permeability to molecules based on their molecular weight and lipid solubilityPresence of specific markersRich in two enzymes: gamma glutamyl transpepti

6、dase (GGTP) (for amino acid transport) and alkaline phosphatase (transport of phsopahte ions) used as marker for BBB.Others: glucose transporter (GLUT-1); endothelial barrier antigen (EBA; unknown function) and antigen recognized by the MRC OX-47 monoclonal antibody (important for cell-to-cell adhes

7、ion); transferrin receptor (transport of ferric ions).Properties of Blood Brain BarriersPresence of tight junctions beBBBBBB1. Neurons have TWO processes called axons and dendrites. Glial cells only have ONE. 2. Neurons CAN generate action potentials. Glial cells CANNOT, however, do have a resting p

8、otential. 3. Neurons HAVE synapses that use neurotransmitters. Glial cells do NOT have chemical synapses. 4. Neurons do NOT continue to divide. Glial cells DO continue to divide. 5. There are many MORE (10-50 times more) glial cells in the brain compared to the number of neurons.Glia are different f

9、rom neurons:1. Neurons have TWO processesNerve CellsNerve CellsNeurons, Glia, Extracellular Space, and BloodNeurons, Glia, Extracellular SBidirectional Communication Partners in the CNSReceiving signals from neighboring neurons and responding to them with release of neuroactive substancesExpress rec

10、eptors for almost all neurotransmitters and neuromodulatorsIncrease of intracellular calcium concentrationMembrane depolarization in astrocytes are common responses to neural activityMetabolically coupled to neural activityBidirectional Communication PaMetabolism of Astrocytes and their Metabolic Co

11、operation with Neurons Glucose Amino acid metabolism Enzymes:glutamine synthetase(glutamate-glutamine cycle);glycogen phosphorylatase (glycogen mobilization); pyruvate carboxylase (anaplerotic synthesis of oxaloacetate); cysteine sulfinate decarboxylase (synthesis of taurine); glycine cleavage system, glycine metabolism. Metabolism of Astrocytes and tThree Types of Metabolic Cooperation of Astrocytes and NeuronsSupply of the energy substrate lactate to ne