Physio Lab Formal Report EXP 2 SEC-E

Experiment 2: Physiology of Nerve (Section E) Laboratory Report Maria Ronalee Dones, Vergel Vergel Jigs Enriquez, Annielle Cyreen Figueroa, Kym Gonzales

Department of Biologial !ienes College of !iene, "ni#ersity of !anto $omas Espa%a, Manila, &'ilippines

#ario #arious us spe speif ifie ie( ( parts parts t'at t'at fun funti tions ons in

Abstract

The nerve is a specialized cell that  recei eceive vess

and and

tran transm smit itss

elec electr tric ic

sign signal alss

reei# reei#ing ing an( transm transmitt itting ing signal signalss namely namely a2ons a2ons an( (en(ri (en(rites tes**

Den(ri Den(rites tes tran transpo sport rt

throughout the body. Voltage gated channels

eletr eletria iall signal signalss to t'e ell ell )o(y )o(y 3'erea 3'ereass

allow the passage an electric signal called an

a2ons a2ons )rin )ring g sign signal alss a3ay a3ay from from t'e t'e soma soma**

acti action on potent potentia ial. l. In this this exper experim iment ent,, the the

 4eurons are lassifie( in t3o 3ays5 aor(ing

threshold

act action

to num)er of its e2tensions an( )ase( on t'e

 potential, and conduction velocity of the

(ire (iret tio ion n of trans transmi miss ssio ion n of info inform rmat atio ion* n*

nerv nervee wer were dete determ rmin ined ed.. Resu Result ltss are are as

$'ere are t'ree types of neurons aor(ing to

 follows: threshold voltage of the nerve is

t'e num)er of e2tensions* First, is a neuron

!mV

t'at is ompose( of a s'ort e2tension (i#i(e(

volt oltage, ge,

while

the

com compound

maximum

"#$

is

%.%!mV&the %.%!mV&the absolute refractory period of the

into

exam examin ined ed nerv nervee is %.'m %.'mse sess in whic which h the the

funtioning as an a2on an( t'e seon( )ran'

relat elativ ivee

imme immedi diat atel elyy

as a (en(rite* $'is type of neuron is alle(

 follows and lastly, lastly, nerve conduction velocity

 pseu(ounipolar neurons* !eon(, is a neuron

is %.%% m(s.

t'at ontains se#eral (en(rites ra(iating from

refra efract ctor oryy

peri period od

t3o

)ran'es

3it'

one

)ran'

t'e soma toget'er 3it' a single long a2on*

I.

ntro!"ction

$'is neuron is terme( as multipolar neurons*

A neur neuron on is a spei speiali alize ze( ( ell ell t'at t'at

$'e t'ir( an( last type of neuron aor(ing to

forms t'e )asi unit of t'e ner#ous system* +t

t'e t'e amou amount nt of e2te e2tens nsio ions ns are are t'e t'e )ipo )ipola lar  r 

is responsi)le in reei#ing an( transmitting

neuro neurons ns** $'is $'is neur neuron on 'as 'as t3o t3o e2te e2tens nsio ions ns

mess messag ages es in a form form of ele eletr tro o'e 'emi mia all

e2'i e2'i)i )iti ting ng

impulses Morgan - Bloom, .//01* +t 'as

lassi lassifi fiati ation on of neuron neuronss are )ase( )ase( on t'e

simi simila larr

leng lengt' t's* s*

$'e $'e

seo seon( n(

(iretion of information transmission* "n(er 

 potential*

t'is type are sensory neurons, motor neurons

$'is sequene (emonstrates t'e ation

an( interneurons* !ensory neurons reei#e

 potential stimulation* Ation potentials are

signals from sensory organs an( transmit

signifiant

t'ese signals t'roug' t'e a2on into t'e entral

ommuniation among neurons use( )y t'e

ner#ous system* 6n t'e ot'er 'an(, motor 

ner#ous

neurons on(ut signals7information from t'e

&almer - !tuart, .//01* +t is pro(ue( )y t'e

orte2 into t'e spinal or( an( e#entually to

opening an( losing of #oltage
t'e

Finally,

'annels

interneurons onnet se#eral neurons in t'e

'annels

entral ner#ous system*

information is generate( as ation potentials

Aor(ing to &a2inos - !tone ./8.1,

mo#e along a2ons* E#ery ner#e is ompose(

neurons reei#e impulse an( transmits it to

of numerous a2ons t'at are parallel to one

t'e follo3ing neuron t'us in(iating t'at

anot'er* >'en t'e stimulation gi#en to a

ner#e impulses funtion as a 'ain reation* A

ner#e is large, more a2ons respon( an( a

neuron is polarize( first )efore it )eomes

ompoun( ation potential is pro(ue(* +t is

stimulate(* +n t'e polarization state resting

t'e summation of all t'e a2ons respon(ing to

mem)rane potential1, t'e neuron 'as a

t'e stimulus )ut it is limite( )eause of t'e

 positi#e eletrial 'arge outsi(e of t'e

restrite( num)er of a2ons per neuron*

mem)rane (ue to t'e e2ess of so(ium ions

During stimulation, t'e 4a 'annels are

an( a negati#e eletrial 'arge insi(e t'e

opene( an( inati#ate(* $'is inati#ation of 

mem)rane )eause of t'e potassium ions

#oltage
 present* Aor(ing to 9e#itan - Kazmare: 

milliseon(s pre#ents t'e entry of so(ium

./8;1, at (epolarization, t'e 4a ions goes

ions* +nati#ation 3ill ontinue an( (uring

into

(epolarization,

t'is time, ation potentials are not generate(

repolarization ours 3'en t'e K ions mo#e

an( annot pass t'roug'* $'is is alle( t'e

(eparts t'e ell* Furt'er K ions 3oul( mo#e

a)solute

out of t'e ell 'yperpolarizing t'e mem)rane*

'annels are responsi)le in 'elping t'e

After 'yperpolarization, t'e K ions an( 4a

mem)rane to go )a: to its resting mem)rane

ions 3ill go )a: to its original state

 potential* After t'e a)solute refratory perio(,

e2'i)iting

 4a 'annels t'at 'a#e reo#ere( from t'e

musles7musle

t'e

ell*

again

ells*

After

t'e

resting

mem)rane

eletrial

signal

t'at

allo3s

system in relaying information

an(

#oltage
Cal(3ell,

so(ium

refratory

.//=1*

potassium $ransfer

'annels

perio(*

for

of 

8<.

&otassium

 pre#ious stimulation, s stronger stimulus is

t'e &o3er 9a)* !ame proe(ure 3as (one for 

t'en applie( to generate a seon( ation

t'e seon( reor(ing eletro(e, e2ept t'e

 potential* $'is perio( requires a stronger 

alligator lips 3ere plae( furt'er a3ay from

stimulus in or(er to generate an ation

t'e stimulus eletro(e*

 potential an( is alle( relati#e refratory  perio(*

Moistene( filter paper strip 3it'

Ation potentials tra#el t'roug'

Ringer@s solution 3as put o#er t'e 3ires in

a2ons qui:ly in or(er to pro(ue a qui: 

t'e ner#e )at' to test its onneti#ity*

response* A2ons are o#ere( 3it' myelin

&o3er9a) 3as turne( on an( 9a) C'art or 

s'eat's t'at inreases t'e rate of on(ution

!ope

on(ution #eloity1* $'e (iameter of an

E2periments Gallery to open CA& !et C'art*

a2on is also a fator in (etermining t'e

From t'e 9a) C'art appliation 3in(o3,

on(ution #eloity*

Maro menu 3as selete( an( t'e $est

$'is e2erise aims to

*/1 3as

laun'e(

follo3e( )y

(etermine t'e t'res'ol( #oltage, CA&, an(

Connetion )utton 'art* $'is automatially

on(ution #eloity of a ner#e*

reor(e( t'e (ata for 8 seon(* A series of  stimulus pulses 3ere seen from t'e monitor 

II.

#etho!ology

t'is in(iates t'at onnetions are 3or:ing

A$ #eas"rement of %ompo"n! Action

an( rea(y to )e use1* After (oing all of t'is, a

Potential

siati ner#e 3as arefully isolate(, 3it'out

Set"p an! calibration of e&"ipment

grasping it 3it' foreps, 3as lai( aross t'e

+n setting up an( ali)rating t'e

3ire eletro(es, ma:ing it sure t'at it is

equipment, re( an( )la: alligator lips 3ere

onnete( 3it' t'e ati#e onnetions*

onnete( /*; apart1 to t'e t3o metal rungs

A$'$ hreshol! voltage an! maximal %AP

on opposites of t'e M9$68.7B 4er#e )at'*

amplit"!e

$'e re( positi#e an( )la: negati#e B4C

+n t'is setion ner#e 3ere gi#en a

onnetor on &o3er 9a) 3as t'enonnete(

series

of

eletrial

stimuli,

ea'

3it'

to t'e positi#e an( negati#e analog output

inreasing amplitu(e* After3ar(s, t'res'ol(

onnetor, respeti#ely* After3ar(s, re( an(

#oltage an( #oltage require( for ma2imum

 )la: lea( from t'e first reor(ing eletro(e

CA& amplitu(e for t'e ner#e 3ere alulate(*

3ere onnete( to t3o of t'e metal rungs of 

From t'e C'art 3in(o3, Maro $'res'ol(

t'e M99$/8.7B 4er#e Bat' 3'ile t'e ?
#oltage 3as li:e(* $'is automatially

 po( onnetor to t'e po( port on +nput 8 of 

stimulate( t'e ner#e an( reor( it for 8*8 s*

>a#eform ursor 3as use( to measure t'e

A ruler 3as use( to (etermine t'e (istane

CA& amplitu(e at ea' stimulus #oltage* $'e

 )et3een t'e )la: negati#e lea(s of ea' t'e

stimulus le#el 3ere t'e first CA& 3as seen

t3o reor(ing eletro(es* From t'e C'art

an( t'e ma2imum CA& amplitu(e 3as also

3in(o3, Maro Con(ution Veloity 3as

note(*

selete(5 t'is reor(s a )lo: of (ata in t3o

A$2$ Refractory Perio!

'annels for 8/ milliseon(s* $'e (ata 3ere

+n t'is part of e2periment, &o3er9a)

t'en reor(e( an( analyze( )y alulating t'e

stimulates t'e ner#e 3it' series of pulses 3it'

on(ution #eloity*

a (ereasing inter#al* +n or(er to (o t'is,

A seletion 3as ma(e 3'i' inlu(es t'e first

minimum stimulus #oltage require( to (ra3 a

CA&* From t'e oom 3in(o3, Mar:er an(

ma2imal CA& from t'e ner#e mV1 3ere

>a#eform Cursor 3as use( to (etermine t'e

(etermine(*

time inter#al for t'e CA& to tra#e5 )et3een

3in(o3,

4e2t,

Maro

from

t'e

Refratory

9a)C'art 3as

t'e t3o reor(ing eletro(es* After t'at,

selete(, 3it' t'e #oltage nearest to t'e

C'annel 8 an( 'annel . 3as selete( an( a

minimum stimulus #oltage* >it' a 8; (ata

mar:er 3as plae( on t'e first CA& pea: an(

 )lo:s an( 8/ milliseon(s (uration, results

t'e 3a#eform ursor o#er t'e seon( CA&

3ere reor(e( an( analyze( )ase( from t'e

 pea:, respeti#ely* $ime (ifferential △t1 3as

follo3ing $3o CA&@s reor(e( in CA&8 in

rea( an( reor(e(* $o get t'e on(ution

ea' )lo: of (ata reor(e( in &art . 3ere

#eloity,

selete(* oom 3in(o3 3as opene( an( (ata

 )et3een t'e t3o reor(ing eletro(es an( t'e

3as

formula foun( appen(i2 8 3as use(*

e2amine( using

mV

>a#eform

Cursor*

measurements for t'e

(istane

Amplitu(e for seon( CA& in ta)le  an( stimulus inter#als 3as reor(e(* $'e relati#e

III.

an(

A$'$ +etermination of threshol! voltage

a)solute

elui(ate(,

refratory

perio(

)y (etermining t'e

3ere

stimulus

inter#al 3'ere t'e amplitu(e of t'e seon(

Res"lts an! +isc"ssion

an! maxim"m %ompo"n! Action Potential

CA& first s'o3s a (erease( an( stimulus

$'e first part of t'e e2periment aims

inter#al 3'ere t'e seon( CA& ompletely

to (etermine t'e t'res'ol( #oltage an(

(isappears, respeti#ely*

ma2imum CA& amplitu(e* As seen in Figure 8, t'e CA& amplitu(e faile( to rise a)o#e

A$$ Nerve %on!"ction *elocity

/mV 3'en t'e stimulus amplitu(e is less t'an

;/mV* +t 3as only 3'en ;/mV 3as applie(

A$2$ +etermination of refractory perio!

t'at t'e CA& amplitu(e starte( to rise* $'e

$a)le 8* CA& amplitu(e #ersus stimulus

CA& amplitu(e ontinue( to rise as t'e

intensity

stimulus amplitu(e 3as inrease(*

Stimulus Interval (ms)

Amplitude of Second CAP

4

-0.050 mV

3.5

-0.150 mV

stimulus amplitu(e no longer 3ent o#er t'e

3.0

-0.225 mV

ma2imum CA& amplitu(e #alue*

2.5

-0.050 mV

2.0

0.000 mV

1.9

-0.05 mV

1.8

-0.02 mV

1.7

-1.50 mV

1.6

-2.50 mV

1.5

-2.50 mV

1.4

-0.025 mV

1.3

-0.075 mV

1.2

-0.025 mV

1.0

-0.200 mV

$'e ma2imum CA& amplitu(e 3as aquire(

at *;/mV 3'en

8/mV of 

stimulus 3as applie(* >'en t'e ma2imum CA& amplitu(e 3as aquire(, inreasing t'e

 4er#es are go#erne( )y t'e all
$a)le 8 s'o3s t'e results o)taine( in

t'e ner#e 3ere alrea(y ati#ate(* $'us CA&

t'e

(i( not rise a)o#e *;/mV e#en if t'e

Ho3e#er, t'e results o)taine( faile( to

stimulus amplitu(e 3as inrease(* $'us, t'e

 pro(ue feasi)le an( i(eal (ata* Errors for 

t'res'ol( #oltage of t'e ner#e is ;/mV 3'ile

t'is may inlu(e mis'an(ling or (amage to

t'e ma2imum CA& is *;/mV*

t'e ner#e or in t'e usage of t'e apparatus*

sai(

su)setion of t'e

e2periment*

Hene, to ompensate for t'ese results, it 3as

also (one in &'ysioE2 =*/*

faile( to pro(ue a seon( potential at a *;mse inter#al*

$a)le .* Results from &'ysioE2

$'e inati#ation of t'e 4a #oltage gate( 'annels is o)ser#a)le 3'en (ou)le  pulses are applie( to a ner#e* As t'e inter#al is (erease(, a stimulus 'ig'er t'an t'e t'res'ol( #oltage is nee(e( to pro(ue a seon( ation potential* A 'ig'er stimulus is nee(e( sine most of t'e 4a 'annels are still reo#ering from t'e pre#ious (epolarization* $'e

a)solute

refratory

perio(

3as

(etermine( )y applie( t'e ma2imum amount of stimulus #oltage at a *;mse inter#al* $'e

a)solute

refratory

perio(

of

t'e

t'e

e2amine( ner#e is *;mse* $'e ner#e nee(s

ner#euse( in &'ysioE2 =*/ 3as set at ./mV*

more t'an *;mse for t'e 4a 'annels to

>it' an inter#al of .;/mse an( 8.;mse, a

return to a resting potential* $'e relati#e

seon(

pro(ue(*

refratory perio( imme(iately follo3s t'e

Ho3e#er, 3'en t'e inter#al 3as lo3ere( to

a)solute refratory perio(* +n t'e relati#e

0/mse, a seon( ation potential 3as not

refratory perio(, a seon( ation potential

o)ser#e(* +t 3as only 3'en t'e stimulus

an )e pro(ue( at a 'ig'er stimulus*

$'e

t'res'ol(

ation

#oltage

potential

3as

of

#oltage 3as raise( to /mV t'at a seon( ation potential 3as o)ser#e(* >'en t'e inter#al 3as furt'er (erease( to /mse, it nee(e( I;mV stimulus to generate a seon(  potential*

$o

(etermine

t'e

ma2imum

refratory perio( of t'e ner#e, t'e ma2imum amount of stimulus, 0/mV, 3as applie(* A 0/mV stimulus generate( a seon( potential 3'en t'e inter#als 3ere lo3ere( to 8;mse an( *;mse* Ho3e#er, a 0/mV stimulus

A.3. Determination of nerve conduction Velocity $'e on(ution #eloity an )e easily alulate( )y :no3ing )ot' t'e (istane t'e ation potential tra#els or )et3een CA&8 (81 an( CA&. (.1 t'e amount of time it ta:es* Veloity 'as t'e units of (istane per  time or m7s*

+n $a)le , t'e gi#en #alue for t'e (istane )et3een reor(ing eletro(es is

Compoun( Ation &otential  Refratory

/*8m1 )ut sine t'e ta)le )elo3 is in m, /*8

 perio(*

is on#erte( to 8/m* $'e time inter#al

n*(*1* Retrie#e( from

 )et3een CA&8 an( CA&. is /*/s )ut sine

'ttp77333*me(iine*mgill*a7p'ysio

t'e ta)le )elo3 is in ms, /*/ is on#erte( to

7#la)7CA&7refrat*'tm

/ms* $'en using t'e formula Goo(man, B* &*, Harper, C* M*, - Boon, A* J* .//=1* &rolonge( ompoun( musle ation potential (uration in ritial $a)le * Calulation of Con(ution Veloity

illness myopat'y* Musle - 4er#e Musle 4er#e, I/01, 8/I/<8/I.*

 4euronal Ation &otential  +mportant features

IV.

of t'e neuronal ation potential

%oncl"sion

$'ere

are

numerous

fators

to

onsi(er 3'en stu(ying ner#e on(ution* First, t'e ner#e must )e stimulate( a)out t'e t'res'ol(

stimulus

to

eliit

an

ation

 potential* !eon(, t'e ner#e nee(s time to repolarize after stimulation* $'ir(, )ot' of t'e former gi#en fators greatly influene t'e on(ution #eloity*

V.

References

C'arateristis of t'e Compoun( Ation &otential* n*(*1* Retrie#e( Fe)ruary .., ./80, from 'ttp77333*me(iine*mgill*a7p'ysio 7#la)7CA&7'arater*'tm

./8I1* Retrie#e( from 'ttp77333*p'ysiology3e)*om7letur  enotes7neuronalationpotential7ne uronalationpotentialrefratorype rio(s*'tml