2_2神经元和神经胶质细胞-胶质细胞

1、1 Neuron : Supporting cells : CNS : neuroglia (glia) PNS : Schwann cells and satellite cells Functions : physical support electrical insulation metabolic exchange blood-brain barrierComposition of Nervous Tissue2Types and Functions of GliaName of Glial CellFunctionAstrocyte (Astroglia)Star-shaped ce

2、lls 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 neurons.Oligo-dend

3、rogliaProvide 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.3Neuroglia in the CNS4Able to replicate!Importance in ne

4、rvous system function is VASTLY underestimated!Evidence is mounting: Nurturing roleSignaling role (Memory?)InflammationPainMany more to come!Neuroglia: Distinguishing Features5Presence of tight junctions between the endothelial cellsOne of the notable features of endothelial cells in comparison to o

5、ther 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 transpeptidase (GGTP) (for amino acid transport) and alkaline phosphatase (transport of phsopahte ions) u

6、sed 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 adhesion); transferrin receptor (transport of ferric ions).Properties of Blood Brain Barriers6BBB71.

7、 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 potential. 3. Neurons HAVE synapses that use neurotransmitters. Glial cells do NOT have chemical synapses. 4. Neurons do NOT co

8、ntinue 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 from neurons:8Nerve Cells9Neurons, Glia, Extracellular Space, and Blood10Bidirectional Communication Partners in the CNSReceivi

9、ng signals from neighboring neurons and responding to them with release of neuroactive substancesExpress receptors for almost all neurotransmitters and neuromodulatorsIncrease of intracellular calcium concentrationMembrane depolarization in astrocytes are common responses to neural activityMetabolic

10、ally coupled to neural activity11Metabolism of Astrocytes and their Metabolic Cooperation 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. 12Three Types of Metabolic Cooperation of Astrocytes and Neurons Supply of the energy substrate