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11Nervous SystemSlide 3Organization of the Nervous SystemPeripheral Nervous System (PNS): Two Functional DivisionsMotor Division: Two Main PartsHistology of Nerve TissueSupporting Cells: NeurogliaAstrocytesSlide 10Microglia and Ependymal CellsSlide 12Oligodendrocytes, Schwann Cells, and Satellite CellsSlide 14Neurons (Nerve Cells)Slide 16Nerve Cell Body (Perikaryon or Soma)ProcessesDendrites of Motor NeuronsAxons: StructureAxons: FunctionMyelin SheathMyelin Sheath and Neurilemma: FormationSlide 24Nodes of Ranvier (Neurofibral Nodes)Unmyelinated AxonsAxons of the CNSRegions of the Brain and Spinal CordNeuron ClassificationSlide 30Comparison of Structural Classes of NeuronsSlide 32Slide 33NeurophysiologySlide 35Electricity DefinitionsElectrical Current and the BodyRole of Ion ChannelsOperation of a Gated ChannelSlide 40Operation of a Voltage-Gated ChannelSlide 42Gated ChannelsElectrochemical GradientResting Membrane Potential (Vr)Slide 46Membrane Potentials: SignalsChanges in Membrane PotentialSlide 49Graded PotentialsSlide 51Slide 52Slide 53Action Potentials (APs)Action Potential: Resting StateAction Potential: Depolarization PhaseAction Potential: Repolarization PhaseAction Potential: HyperpolarizationAction Potential: Role of the Sodium-Potassium PumpPhases of the Action PotentialPropagation of an Action Potential (Time = 0ms)Slide 62Propagation of an Action Potential (Time = 1ms)Slide 64Propagation of an Action Potential (Time = 2ms)Slide 66Threshold and Action PotentialsCoding for Stimulus IntensitySlide 69Slide 70Absolute Refractory PeriodSlide 72Relative Refractory PeriodConduction Velocities of AxonsSaltatory ConductionSlide 76Multiple Sclerosis (MS)Multiple Sclerosis: TreatmentSlide 79Nerve Fiber ClassificationSynapsesSlide 82Types of SynapsesElectrical SynapsesChemical SynapsesSynaptic CleftSynaptic Cleft: Information TransferSlide 88Termination of Neurotransmitter EffectsSynaptic DelayPostsynaptic PotentialsExcitatory Postsynaptic PotentialsSlide 93Inhibitory Synapses and IPSPsSlide 95SummationSlide 97Slide 98NeurotransmittersChemical NeurotransmittersNeurotransmitters: AcetylcholineNeurotransmitters: Biogenic AminesSynthesis of CatecholaminesNeurotransmitters: Amino AcidsNeurotransmitters: PeptidesNeurotransmitters: Novel MessengersSlide 107Functional Classification of NeurotransmittersSlide 109Neurotransmitter Receptor MechanismsChannel-Linked ReceptorsSlide 112G Protein-Linked ReceptorsG Protein-Linked Receptors: MechanismSlide 115G Protein-Linked Receptors: EffectsNeural Integration: Neuronal PoolsSlide 118Slide 119Types of Circuits in Neuronal PoolsSlide 121Types of Circuits in Neuronal PoolsSlide 123Patterns of Neural ProcessingSlide 125Development of NeuronsAxonal GrowthN-CAMs111Fundamentals of the Nervous System and Nervous TissuePart A2Nervous SystemThe master controlling and communicating system of the bodyFunctionsSensory input – monitoring stimuli occurring inside and outside the body Integration – interpretation of sensory inputMotor output – response to stimuli by activating effector organs3Nervous SystemFigure 11.14Organization of the Nervous SystemCentral nervous system (CNS) Brain and spinal cordIntegration and command center Peripheral nervous system (PNS)Paired spinal and cranial nervesCarries messages to and from the spinal cord and brain5Sensory (afferent) divisionSensory afferent fibers – carry impulses from skin, skeletal muscles, and joints to the brainVisceral afferent fibers – transmit impulses from visceral organs to the brain Motor (efferent) division Transmits impulses from the CNS to effector organsPeripheral Nervous System (PNS): Two Functional Divisions6Somatic nervous systemConscious control of skeletal musclesAutonomic nervous system (ANS)Regulates smooth muscle, cardiac muscle, and glandsDivisions – sympathetic and parasympatheticMotor Division: Two Main Parts7The two principal cell types of the nervous system are:Neurons – excitable cells that transmit electrical signalsSupporting cells – cells that surround and wrap neuronsHistology of Nerve Tissue8The supporting cells (neuroglia or glial cells):Provide a supportive scaffolding for neuronsSegregate and insulate neuronsGuide young neurons to the proper connections Promote health and growthSupporting Cells: Neuroglia9Most abundant, versatile, and highly branched glial cellsThey cling to neurons and their synaptic endings, and cover capillariesFunctionally, they:Support and brace neuronsAnchor neurons to their nutrient suppliesGuide migration of young neuronsControl the chemical environment by buffering the potassium and recapturing neurotransmittersAstrocytes10AstrocytesFigure 11.3a11Microglia – small, ovoid cells with spiny processesPhagocytes that monitor the health of neuronsEpendymal cells – range in shape from squamous to columnarThey line the central cavities of the brain and spinal columnThey help circulate the cerebrospinal fluidMicroglia and Ependymal Cells12Microglia and Ependymal CellsFigure 11.3b, c13Oligodendrocytes – branched cells that wrap CNS nerve fibers Schwann cells (neurolemmocytes) – surround fibers of the PNSSatellite cells surround neuron cell bodies with gangliaOligodendrocytes, Schwann Cells, and Satellite Cells14Figure 11.3d, eOligodendrocytes, Schwann Cells, and Satellite Cells15Structural units of the nervous systemComposed of a body, axon, and dendritesLong-lived, amitotic, and have a high metabolic rateTheir plasma membrane functions in:Electrical signaling Cell-to-cell signaling during developmentNeurons (Nerve Cells)16Neurons (Nerve Cells)Figure 11.4b17Contains the nucleus and a nucleolus Is the major biosynthetic center Is the focal point for the outgrowth of neuronal processes Has no centrioles (hence its amitotic nature)Has well-developed Nissl bodies (rough ER)Contains an axon hillock – cone-shaped area from which axons ariseNerve Cell Body (Perikaryon or Soma)18Armlike extensions from the somaCalled tracts in the CNS and nerves in the PNSThere are two types: axons and dendrites Processes19Short, tapering, and diffusely branched processesThey are the receptive, or input, regions of the neuron Electrical signals are conveyed as graded potentials (not action potentials)Dendrites of Motor Neurons20Slender processes of uniform diameter
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