Neuron

STRUCTURE OF NEURON AND ITS TYPES

1. NEURON
PRESENTED BY: Ms. SUKHRAJ KAUR
M.Sc. NURSING (PEDIATRICS)
ASHOKA INSTITUTE OF NURSING, PATIALA

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Neuronsarethecellsconsideredtobethe
structuralandfunctionalunitofthenervous
system.
Theyareresponsiblefortheelectrical
signalsthatcommunicateinformationabout
sensations,andthatproducemovementsin
responsetothosestimuli,alongwith
inducingthoughtprocesseswithinthebrain.
Animportantpartofthefunctionofneurons
isintheirstructure,orshape.

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 Cellbody
 Dendrites
 Axon
 Axonterminal


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Themainportionofthe
neuroniscalledcell
body.
Inthecenterofthecell
bodyisthenucleusof
thecell,wherethe
chromosomes that
containallofthegenetic
materialarestored.

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Conti..
Thisisalsothepartofthecellthat
createsmRNAforcellreplication.
Thecellbodyrelaystheinformation
downtotheaxon

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DENDRITES
Dendritesarebranch-likestructures
extendingawayfromthecellbody,and
theirjobistoreceivemessagesfrom
otherneuronsandallowthosemessages
totraveltothecellbody.
Dendritesarespecializedtoreceive
signalsfromneighboringneuronsand
carrythembacktothecellbody

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Itisatube-likestructurethatcarries
anelectricalimpulsefromthecell
bodytothestructuresatopposite
endoftheneuroni.eaxonterminals,
whichcanthenpasstheimpulseto
anotherneuron.

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Conti..
Myelinsheathisalsopresentaroundthe
axonsiscalledasmyelinatednerve
fibers.
Thismyelinsheathfurtherconsistof
protein-lipidcomplexcalledasschwann
cells.
Thereisashortgapbetweenthetwo
segmentsofaxonistheNodesof
Ranvierwherethesignalsgetrecharged

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AXON TERMINAL
AnAxonterminalistheveryendofa
branchofnerveaxon.AxonTerminal
isthelaststepfortherelayof
informationinsidetheneuron.

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-Electrical Communication
-Chemical Communication
How do Neurons Communicate?

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Actionpotentialisanelectricalcurrent
sentdowntheaxon.
Theactivitywithintheneuronsis
electrical.Thiscurrentcausesthe
neuronto“fire”

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Action potentials travel down the axon
like a wave of energy

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TheSynapseisthespaceOrsynapticgap
betweenneurons
•Informationmustbetransmittedacrossthe
synapsetootherneuronsviathe
neurotransmitters.
•Thisisanelectrochemicalprocess

17. Let’s Review!

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Neurotransmittersarechemicalsubstances
thatresideintheaxonterminals
•Theycommunicatetootherneuronsby
bindingtoreceptorsonneighboring
neurons

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Thecommunicationbetweenneurons
ischemical

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TYPES OF NEURONS
Therearemanyneuronsinthenervous
system—anumberinthetrillions.
Theycanbeclassifiedas:
Dependinguponthenumberofpoles
1.UnipolarNeurons
2.BipolarNeurons
3.MultipolarNeurons

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Conti..
Dependinguponthefunctions
1.Motorneurons
2.Sensoryneurons

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Depending upon the number of poles

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Conti..
1.UnipolarNeurons
Theseneuronshaveasinglepole,
fromwhichthebothaxonand
dendritesarise.
Trueunipolararepresentonlyin
embryonicstageinhumanbeing.

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Conti..
2.BipolarNeurons
Theseneuronshavetwopoles,one
foraxon&otherfordendrite.
Bipolorneuronsarefoundinthe
vestibular,cochlearganglia,inthe
nasalolfactoryepithelium&bipolar
cellsintheretinaoftheeye.

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Conti..
3.MultipolarNeurons
Thesehavemanypoles.
Oneofthepolegivesrisetoaxon
andallothertodendrites.
InCNSmostoftheneuronsare
multipolar.

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Depending upon the functions
1.Motorneurons
Thesearealsoknownasefferent
nervecells.
ThesecarryimpulsesfromCNSto
theeffectororganlikemuscles,
glands,bloodvessels.
Theseneuronshaveverylongaxon
andshortdendrites.

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Conti..
2.Sensoryneurons
Thesearealsoknownasafferent
nervecells.
Thesecarryimpulsesfromeffector
totheCNS.
Theseneuronshaveveryshort
axonandlongdendrites.