Functional Organization of Nervous Tissue
اسلاید 1: 11-1Functional Organization of Nervous Tissue
اسلاید 2: 11-2The Nervous SystemComponentsBrain, spinal cord, nerves, sensory receptorsResponsible forSensory perceptions, mental activities, stimulating muscle movements, secretions of many glandsSubdivisionsCentral nervous system (CNS)Peripheral nervous system (PNS)
اسلاید 3: 11-3Central Nervous SystemConsists ofBrainLocated in cranial vault of skullSpinal cordLocated in vertebral canalBrain and spinal cordContinuous with each other at foramen magnum
اسلاید 4: 11-4Peripheral Nervous SystemTwo subcategoriesSensory or afferentMotor or efferentDivisionsSomatic nervous systemAutonomic nervous system (ANS)Sympathetic ParasympatheticEnteric
اسلاید 5: 11-5Nervous System Organization
اسلاید 6: 11-6Cells of Nervous SystemNeurons or nerve cellsReceive stimuli and transmit action potentialsOrganizationCell body or somaDendrites: InputAxons: OutputNeuroglia or glial cellsSupport and protect neurons
اسلاید 7: 11-7Types of NeuronsFunctional classificationSensory or afferent: Action potentials toward CNSMotor or efferent: Action potentials away from CNSInterneurons or association neurons: Within CNS from one neuron to anotherStructural classificationMultipolar, bipolar, unipolar
اسلاید 8: 11-8Neuroglia of CNSAstrocytesRegulate extracellular brain fluid compositionPromote tight junctions to form blood-brain barrierEpendymal CellsLine brain ventricles and spinal cord central canalHelp form choroid plexuses that secrete CSF
اسلاید 9: 11-9Neuroglia of CNSMicrogliaSpecialized macrophagesOligodendrocytesForm myelin sheaths if surround axon
اسلاید 10: 11-10Neuroglia of PNSSchwann cells or neurolemmocytesWrap around portion of only one axon to form myelin sheathSatellite cellsSurround neuron cell bodies in ganglia, provide support and nutrients
اسلاید 11: 11-11Myelinated and Unmyelinated AxonsMyelinated axonsMyelin protects and insulates axons from one anotherNot continuousNodes of RanvierUnmyelinated axons
اسلاید 12: 11-12Electrical SignalsCells produce electrical signals called action potentialsTransfer of information from one part of body to anotherElectrical properties result from ionic concentration differences across plasma membrane and permeability of membrane
اسلاید 13: 11-13Sodium-Potassium Exchange Pump
اسلاید 14: 11-14Membrane Permeability
اسلاید 15: 11-15Ion ChannelsNongated or leak channelsAlways open and responsible for permeabilitySpecific for one type of ion although not absoluteGated ion channelsLigand-gatedOpen or close in response to ligand binding to receptor as AChVoltage-gatedOpen or close in response to small voltage changes
اسلاید 16: 11-16Resting Membrane PotentialCharacteristicsNumber of charged molecules and ions inside and outside cell nearly equalConcentration of K+ higher inside than outside cell, Na+ higher outside than insideAt equilibrium there is very little movement of K+ or other ions across plasma membrane
اسلاید 17: 11-17Changes in Resting Membrane PotentialK+ concentration gradient alterationsK+ membrane permeability changesDepolarization or hyperpolarization: Potential difference across membrane becomes smaller or less polarHyperpolarization: Potential difference becomes greater or more polar Na+ membrane permeability changesChanges in Extracellular Ca2+ concentrations
اسلاید 18: 11-18Local PotentialsResult fromLigands binding to receptorsChanges in charge across membraneMechanical stimulationTemperature or changesSpontaneous change in permeabilityGradedMagnitude varies from small to large depending on stimulus strength or frequencyCan summate or add onto each other
اسلاید 19: 11-19Action PotentialsSeries of permeability changes when a local potential causes depolarization of membranePhasesDepolarizationMore positiveRepolarizationMore negativeAll-or-none principleCamera flash system
اسلاید 20: 11-20Action Potential
اسلاید 21: 11-21Refractory PeriodSensitivity of area to further stimulation decreases for a timePartsAbsoluteComplete insensitivity exists to another stimulusFrom beginning of action potential until near end of repolarizationRelativeA stronger-than-threshold stimulus can initiate another action potential
اسلاید 22: 11-22Action Potential FrequencyNumber of potentials produced per unit of time to a stimulusThreshold stimulusCause an action potentialMaximal stimulusSubmaximal stimulusSupramaximal stimulusInser
اسلاید 23: 11-23Action Potential Propagation
اسلاید 24: 11-24Saltatory Conduction
اسلاید 25: 11-25The SynapseJunction between two cellsSite where action potentials in one cell cause action potentials in another cellTypesPresynapticPostsynaptic
اسلاید 26: 11-26Chemical SynapsesComponentsPresynaptic terminalSynaptic cleftPostsynaptic membraneNeurotransmitters released by action potentials in presynaptic terminalSynaptic vesiclesDiffusionPostsynaptic membraneNeurotransmitter removal
اسلاید 27: 11-27Neurotransmitter Removal
اسلاید 28: 11-28Summatio
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