Subdivisions of Nervous SystemFunctions of the Nervous SystemSubdivisions of Nervous SystemWhere Are My Nerves?Functions of The Nervous SystemOverview of Nervous SystemSlide 7Slide 9Neuroglial Cells of CNSSlide 11AstrocyteSlide 13Neuroglia: Support CellsMicrogliaSlide 16Oligodendrocyte :forms myelin in the CNSSchwann Cell or NeurolemmocyteSlide 19The Structural Cell of the Nervous System: The NeuronWhich Are Found in CNS?The Neuron : Structural Cell of NSA Representative NeuronStructure of a NeuronVariation in Neural StructureTypes of NeuronsFundamental Types of NeuronsIt All Starts at The Sensory ReceptorReflex ArchAfferent Neuron – Moving away from a central organ or point Relays messages from receptors to the CNSSensory neuronsMotor neuronSlide 33Slide 34Properties of NeuronsNeurons Communicate Via Chemicals Called NeurotransmittersPresynaptic To Postsynaptic Membrane CommunicationNeurons: They Never Really Touch!Synapses between NeuronsHow Do Neurons Work? How Do they React, Conduct, Secrete?Nerve Impulse Relies on the ELECTROCHEMISTRY of the Plasma MembraneBefore Neurons Conduct or “Propagate” an impulse they are in the RESTING stateSENDING INFORMATION: NERVE IMPULSENotice the INSIDE of the Cell is Negative….giving a -70mVSlide 45GatesSlide 47Resting Membrane Potential. Its Tested ….Like the Battery.REMEMBER Which side is positive and which is negativeSlide 50Types Of Ion ChannelsVoltage-Regulated ChannelsIonic Basis of Resting Membrane PotentialWhat happens to Plasma Membrane of Neuron to Generate a AP?WHAT IS THRESHOLD?Sodium’s Dual Gates: Both Must be Open during DEPOLARIZATION!Action Potential = Nerve ImpulseSending information (Cont.)INSIDE-0UT!!!GO!!!The Myelin SheathSlide 62Saltatory ConductionSlide 64CONDUCTION VELOCITIESNeuron Cell Body LocationSlide 67Slide 68Slide 69B. Graded PotentialSodium-Potassium Pump: (Remember Me?)Na-K Pump: How it WorksREMEMBERING THE SYNAPSE…….POSTSYNAPTIC POTENTIALSC. EPSP and IPSPE. NeurotransmittersSome NTs Stimulate AP, Some Inhibit APInhibitory GABA-ergic SynapseRead this To Recap Action PotentialSubdivisions of Nervous SystemFunctions of the Nervous System•Sensory input – gathering information–To monitor changes occurring inside and outside the body–Changes = stimuli•Integration–To process and interpret sensory input and decide if action is neededEffect or Action The result of the integration. A reflex or response.Subdivisions of Nervous SystemTwo major anatomical subdivisions•Central nervous system (CNS)–brain and spinal cord enclosed in bony coverings•Peripheral nervous system (PNS)– Every Nerve outside of the CNS!–NERVE: a bundle of neurons–GANGLIAN: a cluster of neuron bodies ( resembles a knot)Where Are My Nerves?•We have :•12 Cranial Nerves•33 Spinal NervesFunctions of The Nervous System•Regulates Internal Body Metabolism(Body temp., urine volume, blood volume, gas exchange, circulation movement)•Links To External Environment ( Interpreter) Sensory Devices-seeing, smelling, hearing (pressure, hot cold) Emotion Response to external environment ( these drives satisfy physical needs to preserve homeostasis) thirst, hunger,rest sexualityOverview of Nervous System•Endocrine and nervous system maintain internal coordination–endocrine = chemical messengers (hormones) delivered to the bloodstream–nervous = three basic steps•sense organs receive information•brain and spinal cord determine responses•brain and spinal cord issue commands to glands and muscles•Sensory (afferent) divisions (receptors to CNS) (Leads to…with stimuli)–visceral sensory and somatic sensory division•Motor (efferent) division (CNS to effectors)–visceral motor division (ANS) effectors: cardiac, smooth muscle, glands•sympathetic division (action)•parasympathetic division (digestion)–somatic motor division effectors: skeletal muscleFunctional Divisions of PNS•Cells of the Nervous System Are Specialized and Are of Several TypesNeuroglial Cells of CNSTHESE ARE SUPPORT CELLS THAT OUTNUMBER THE NEURONSAstrocyte•Astrocytes–Abundant, star-shaped cells–Brace neurons w/ their perivascular feet.–Form barrier between capillaries and neurons–Control the chemical environment of the brain; Secrete Neural Growth factors–Convert Glucose to lactateASTROCYTES ALSO…….Most common glial cell in CNSForm blood-brain barrierHelp with ion uptakeHelp with neurotransmitter uptakeMany glucose transport carriers, which helpmove glucose from blood to brainNeuroglia: Support Cells•Ependymal cells–Lines the ventricles of the brain Spaces filled with CSF)and spinal Chord–Produced Cerebral Spinal Fluid–Assists in the Circulation of CSFFigure 7.3b–cMicroglia•Phagocytic cells that engulf and destroy microbes and debris in the CNS.•Active in response to immune response or injury•Spider-like in appearanceFigure 7.3eNeuroglia: Support Cells•Satellite cells–Protect sensory neuron cell bodies in the dorsal root ganglia•Schwann cells–Form myelin sheath in the peripheral nervous system (PNS)Oligodendrocyte :forms myelin in the CNS•Myelin: composed from lipids (contains cholesterol)•Creates nodes of ranvier•This insulation causes saltatory conduction, a more rapid conduction than w/out insulationSchwann Cell or Neurolemmocyte•The neurolemmocyte is the neuroglia cell that surrounds the axon of the neuron in the PNS. HereSchwann Cell or Neurolemmocyte•IN FACT THIS CELL produces the myelin sheath around the axon in the PNS…yeah!!•Neurolemmna- The outer nucleated layer cytoplasmic layer of the neurolemmocyte•Nodes of Ranviar- Periodic Gaps between the myelin sheath.The Structural Cell of the Nervous System: The Neuron SPECIAL CHARACTERISTICS:• loses its ability to divide (no centrioles) There are exceptions to this rule…hippocampus and olfactory neurons.• consumes a great deal of energy; many mitrochondria are present•THEY CAN BE VERY LARGE! Some are as long as one meter.Which Are Found in CNS?•Ependymal•Microglia•Astrocytes•Oligodendrocytes•Satellite and Schwann Cells are found in PNSThe Neuron : Structural Cell of NS•The Basic information processing unit of the NS.•Conducts impulses from one part of body to another•Has 3 distinct parts:1. Cell Body ( Soma)2. Dendrites3. AxonA Representative NeuronStructure of a Neuron•Cell body = perikaryon = soma–single, central nucleus with large nucleolus–cytoskeleton of microtubules and