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Chapter 34Neural ControlNervous SystemFunctions (Neurons)Sensory
inputDetect & receiveInternal or externalIntegrationProcess
& interpretMotor outputMuscles & glands
Nerve PathwayNervous System TypesNerve NetCnidariansSensory
neurons in epidermisMotor neurons in all tissues
Nervous System TypesLadder-LikePlathyhelminthesLong
nervesGanglia (brain)Integration
Nervous System TypesAdvanced InvertebratesMore
advancedCephalizedBrainVentral nerve cordBranching nerves
Nervous System TypesVertebrateMore advancedMany more neurons1
million in insectsVertebrates 1,000-1 billion more!Two
divisionsCentral nervous systemPeripheral nervous system
Nerve CellsNeuronPrimary cell typeConducts
impulsesNeuroglialSupport/nourish neuronNon-excitatory9:1 ratio
Neuroglial CellsCNS
Neuroglial CellsPNS
NeuronsCharacteristicsExcitableLongevityHigh Metabolic
RateSometimes LargeAmitoticMay Regenerate
NeuronsSensory (afferent)Detects stimuliCarry signal to
CNSInterneuron (association)Transmit between neurons in CNSMotor
(efferent)Carry signal to muscle or
glandNeuronsAxonSomaDendriteMyelin sheathAxon terminalSynapse
NeuronsMyelin SheathInsulatingMyelinated transmit faster
NeuronsSynapseChemicalElectrical
NeurotransmittersAcetylcholineMost commonNeuromuscular
junctionNorepinephrineInvoluntary functionsDopamineMany
functionsBehavior & mental abilitySerotoninMoodSleep
Nerve ImpulseResting potentialNa+ higher outside of cellK+
higher inside of cell
Nerve Impulse
Nerve Impulse
Nerve ImpulseSodium gates openSodium moves into cellAction
potential startsPotassium gates openPotassium moves out of
cellElectrical charges across membrane switchWave of charge moves
along axon
Nerve ImpulseMyelinated axons transmit signal faster
Nerve ImpulseAll-or-nothingRefractory periodCannot respond to
signal
Central Nervous SystemBrain & spinal cordWhite
mattermyelinatedGrey matterunmyelinated MeningesCerebrospinal
fluid
Central Nervous SystemBrainAlligator0.003% body weightSperm
whale0.06%Rat0.5%Human2%
BrainCerebrumIntegrates & analyzesFrontal lobemotor
controlParietal lobesensory from bodyOccipital lobevision Temporal
lobehearing, emotions
BrainThalamusRelay stationMemories,
emotionsHypothalamusHomeostasisSleep, sex, thirst, etc.Medulla
OblongataHeart rate, breathing, blood pressureInvoluntary muscle
contractions
BrainPonsFine-tune breathingHearing/sight
reflexesCerebellumCoordinate movementGordonWeebles
BrainLimbic SystemLearningMemoryFear & pleasureFacial
expressions
Peripheral Nervous SystemCranial & spinal nerves
Peripheral Nervous System12 pairs Cranial Nerves31 pairs Spinal
Nerves
Peripheral Nervous SystemSomaticSensory signals to skeletal
muscleSynapses in brain or spinal cordReflexes
Peripheral Nervous SystemReflex arc
Peripheral Nervous SystemAutonomicInvoluntary Cardiac
muscleSmooth muscleGlands
Autonomic Nervous SystemSympatheticFight or
flightExcitementExerciseEmergencyEmbarassmentParasympatheticRest
& digestDigestionDefecationDiuresisAutonomic Nervous
SystemOrganParasympatheticSympatheticEye
(pupil)ConstrictDilateGlandsStimulates secretionInhibits
secretionHeart muscleSlows & steadies rateIncreases rate &
forceLungsConstricts bronchiolesDilates bronchiolesDigestive
tractIncreases digestionDecreases digestionBladderPromotes
voidingInhibits voidingMental activityNo effectIncreases
alertnessAutonomic Nervous System
Autonomic Nervous System
