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SECTION 12-4Neurophysiology: Ions and Electrical Signals(Fisiologi neuron: Ions dan Signal listri!

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Cell "e"#rane

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Ionic Relations in the Cell

The sodium/potassium ATPase produces a concentration of Na+ outside the cell that is

some 10 times greater than that inside the cell

a concentration of K+ inside the cell some 20times greater than that outside the cell.

The concentrations of chloride ions (Cl! andcalcium ions (Ca2+! are also maintained at

greater le"els outside the cell #$C#PT that someintracellular mem%rane%ounded compartmentsma& also ha"e high concentrations of Ca2+ (greeno"al!

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Ada ' saluran ger%ang

Kimia "oltase dan me)ani)

Three types o$ acti%e channels-che"ically regulated channels-%oltage-regulated channels

-"echanically regulated channels

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&ated Channels (saluran ger#ang!

Figure 12.13

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E'cita#le cell: NE)ON

structure:

dendrites *ith synapses

#ody

a'on *ith "yelin and synapses

$unction:

thresholding o$ input signals

integration (te"poral and

spacial! o$ input signals

generation o$ action potentials

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Intoduction to the )esting +otential (pengantartentang ,e#ran +otensial Istirahat!

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ction +otential . // ' NOT0IN&

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Appears *hen region of ecita%le mem%rane

depolari,es to threshold -teps in"ol"ed

em%rane depolari,ation and sodium

channel acti"ation (mem%ran depolarisasiNa+ tera)ti"asi!

-odium channel inacti"ation ()emudiannon a)tif!

Potassium channel acti"ation (K+tera)ti"asi !repolarisasi

eturn to normal permea%ilit& ()em%ali

)e normal!

ction +otential (+otensial asi!

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Figure 12.16.2

Figure 121 The &eneration o$ an ction+otential

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ction +otential

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ction +otential . opening o$ sodiu" and potassiu" channels

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ction +otential

K+

-channels

Na+-channels

Vm

excitable cell

time

resting potential

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T&pe A fi%ers

T&pe fi%ers

T&pe C fi%ers

ased on diameter m&elination andpropagation speed (erdasar m&elinasi dan)ecepatan propagasi!

'on classi$ication (3lasi$iasi ason!

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uscle tissue has higher resting potential (Ple%ih tinggi!

uscle tissue action potentials are longer lasting(lama %era)hir!

uscle tissue has slo*er propagation of action

potentials (propagasi le%ih lam%at!

Animation: The action potentialPLAY

,uscle action potential %ersus neural actionpotential

http://facstaff.bloomu.edu/gwassmer/ap1/media_cd/ip/systems/actpot.htmlhttp://facstaff.bloomu.edu/gwassmer/ap1/media_cd/ip/systems/actpot.html

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