Nervous Tissue and FunctionFunctional Classification of the Peripheral Nervous SystemOrganization of the Nervous SystemSlide 4Slide 5Nervous Tissue: Support Cells (Neuroglia)Nervous Tissue: Support CellsSlide 8Slide 9Slide 10Slide 11Slide 12Neuron Cell Body Names and LocationsAxons and Connection(s) to Other NeuronsNerve Fiber CoveringsSlide 16Functional Classification of NeuronsSlide 18Principles of ElectricityDefinitionsRole of Membrane Ion Channels (Protein “Gates”)Slide 22Resting Membrane PotentialSlide 24Membrane Potentials That Act as SignalsSlide 26Slide 27Slide 28Slide 29Slide 30Action Potential (AP)Slide 32Slide 33Slide 34Slide 35Threshold StimulusSlide 37Slide 38Slide 39Multiple Sclerosis (MS)Slide 41The Reflex ArcTypes of Reflexes and RegulationSlide 44Two Kinds of SynapsesHow Neurons Communicate at SynapsesSlide 47Slide 48Slide 49Slide 50Slide 51Slide 52Slide 53Slide 54Excitatory Synapses and EPSPsInhibitory Synapses and Inhibitory Postsynaptic Potential (IPSPs)Slide 57Chemical Classes of NeurotransmittersNervous Tissue and FunctionFunction of the Nervous SystemOrganization (Structural and Functional)Supporting Cells of the Nervous SystemAnatomy of a NeuronClassification of Neurons by FunctionGraded and Action PotentialsMyleination and MSReflexesSynapsesEPSPs and IPSPsNeurotransmittersFunctional Classification of the Peripheral Nervous SystemOrganization of the Nervous Systemand reflexes inhibitory stimulatoryFigure 11.2Central nervous system (CNS)Brain and spinal cordIntegrative and control centersPeripheral nervous system (PNS)Cranial nerves and spinal nervesCommunication lines between theCNS and the rest of the body ParasympatheticdivisionConserves energyPromotes house-keeping functionsduring restMotor (efferent) divisionMotor nerve fibersConducts impulses from the CNSto effectors (muscles and glands)Sensory (afferent) divisionSomatic and visceral sensorynerve fibersConducts impulses fromreceptors to the CNSSomatic nervoussystemSomatic motor(voluntary)Conducts impulsesfrom the CNS toskeletal musclesSympathetic divisionMobilizes bodysystems during activity Autonomic nervoussystem (ANS)Visceral motor(involuntary)Conducts impulsesfrom the CNS tocardiac muscles,smooth muscles,and glandsStructureFunctionSensory (afferent)division of PNS Motor (efferent) division of PNSSomatic sensoryfiber Visceral sensory fiberMotor fiber of somatic nervous systemSkinStomachSkeletalmuscleHeartBladderParasympathetic motor fiber of ANSSympathetic motor fiber of ANSNervous Tissue and FunctionFunction of the Nervous SystemOrganization (Structural and Functional)Supporting Cells of the Nervous SystemAnatomy of a NeuronClassification of NeuronsNeuron Function Graded and Action PotentialsMyleination and MSReflexesSynapsesEPSPs and IPSPsNeurotransmittersNervous Tissue: Support Cells (Neuroglia)Astrocytes•Abundant, star-shaped cells•Brace neurons•Form barrier between capillaries and neurons•Control the chemical environment of the brain•Help transfer nutrients between capillaries and neurons•Mop up and recapture potassium ions and neurotransmitters"Star cells connect and protect"Nervous Tissue: Support CellsMicroglia•Spider-like phagocytes•Dispose of debris by phagocytosis•Monitor neuron health"Tiny garbage spiders"Brain orspinal cordtissueEpendymalcellsFluid-filled cavity• Range in shape from squamous to columnar• May be ciliated• Line the central cavities of the brain and spinal column• Separate the CNS interstitial fluid from the cerebrospinal fluid in the cavitiesEpendymal Cells (literally, “wrapping garment” cells)Nervous Tissue: Support CellsOligodendrocytes•Produce myelin sheath around nerve fibers in the central nervous system"Oligos insulate"Nervous Tissue: Support CellsSchwann cells•Form myelin sheath in the peripheral nervous system•Satellite cells•Surround neuron cell bodies in the PNSSchwann cells(forming myelin sheath)Cell body of neuronSatellitecellsNerve fiberNervous Tissue and FunctionFunction of the Nervous SystemOrganization (Structural and Functional)Supporting Cells of the Nervous SystemAnatomy of a NeuronClassification of NeuronsNeuron Function Graded and Action PotentialsMyleination and MSReflexesSynapsesEPSPs and IPSPsNeurotransmittersFigure 11.4bDendrites(receptive regions)Cell body(biosynthetic centerand receptive region)NucleolusNucleusNissl bodiesAxon(impulse generatingand conducting region)Axon hillockNeurilemmaTerminalbranches Node of RanvierImpulsedirectionSchwann cell(one inter-node)Axonterminals(secretoryregion)(b)(Rough ER)Neuron Cell Body Names and LocationsClusters of cell bodies Bundles of nerve fibers (neuronal processes)CNS Nuclei Tracts White matter -dense myelinated fibers Gray matter- unmyelinated fibers and cell bodiesPNS Ganglia Nerves (bundles of axons)Axons and Connection(s) to Other NeuronsSynapseNerve Fiber CoveringsIn the PNS, Schwann cells produce myelin sheaths in jelly-roll like fashionNodes of Ranvier – gaps in myelin sheath along the axonIn the CNS, oligodendrocytes produce myelin sheaths and have no neurilemma (so cannot regenerate if damaged).In multiple sclerosis (MS) the myelin sheaths are destroyed (autoimmunity) leading to poorly functioning musclesNervous Tissue and FunctionFunction of the Nervous SystemOrganization (Structural and Functional)Supporting Cells of the Nervous SystemAnatomy of a NeuronClassification of Neurons by FunctionGraded and Action PotentialsMyleination and MSReflexesSynapsesEPSPs and IPSPsNeurotransmittersFunctional Classification of NeuronsSensory (afferent) neurons•Carry impulses from the sensory receptors•Cell bodies outside the CNSoCutaneous sense organsoProprioceptors – detect stretch or tensionFrom skin receptors, muscles and tendonsMotor (efferent) neurons•Carry impulses from the central nervous system•Cell bodies inside the CNSInterneurons (association neurons)•Found in neural pathways in the central nervous system•Connect sensory and motor neurons•Cell bodies inside the CNSNervous Tissue and FunctionFunction of the Nervous SystemOrganization (Structural and Functional)Supporting Cells of the Nervous SystemAnatomy of a NeuronClassification of Neurons by FunctionGraded and Action PotentialsMyleination and