Physio Lab Formal Report EXP 2 SEC-E

Experiment 2: Physiology of Nerve

Experiment 2: Physiology of Nerve (Section E)

(Section E)

Laboratory Report

Laboratory Report

Maria Ronalee Dones, Vergel Jigs Enriquez, Annielle Cyreen Figueroa, Kym ergel Jigs Enriquez, Annielle Cyreen Figueroa, Kym GonzalesGonzales

Department of Biologial !ienes Department of Biologial !ienes College of !iene,

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

Espa%a, Manila, &'ilippines

Abstract Abstract

The nerve is a specialized cell that  The nerve is a specialized cell that  rrececeieiveves s anand d trtranansmsmitits s elelecectrtric ic sisigngnalalss throughout the body. Voltage gated channels throughout the body. Voltage gated channels allow the passage an electric signal called an allow the passage an electric signal called an ac

actition on potpotententiaial. l. In In ththis is exexperperimimentent, , ththee tthhrreesshhoolld d vvololttaagege, , cocommppoouund nd acacttiionon  potential,

 potential, and and conduction conduction velocity velocity of of thethe ne

nervrve e wewerre e dedetetermrminineded. . ReResusultlts s arare e asas  follows:

 follows: threshold threshold voltage voltage of of the the nerve nerve isis 

!!mmV V wwhhiille e tthhe e mmaaxxiimmuum m ""##$ $ iiss %.%!mV

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

examaminined ed nenervrve e is is %.'%.'mmseses s in in whwhicich h ththee rrelelatativive e rrefefraractctorory y pepeririod od imimmemedidiatatelelyy  follows

 follows and and lastlylastly, , nerve nerve conduction conduction velocityvelocity is %.%% m(s.

is %.%% m(s.

I.

I. ntro!"ctionntro!"ction

A

A neneururon on is is a a spspeieialializeze( ( elell l t't'atat forms t'e )asi unit of t'e ner#ous system* +t forms t'e )asi unit of t'e ner#ous system* +t is responsi)le in reei#ing an( transmitting is responsi)le in reei#ing an( transmitting me

messssagages es in in a a foform rm of of eleleetrtroo'e'emimiaall impulses Morgan - Bloom, .//01* +t 'as impulses Morgan - Bloom, .//01* +t 'as

#ar

#arioious us spspeeififieie( ( parparts ts t't'at at fufunntitions ons inin re

reei#ei#ing ing an( an( tratransmnsmittitting ing sigsignalnals s namnamelyely a2on

a2ons an( (ens an( (en(ri(ritestes* * DenDen(ri(rites ttes tranransposportrt ele

eletrtriaial l sigsignalnals s to to t'e t'e elell l )o()o(y y 3'e3'ereareass a2o

a2ons ns )r)rining g sisigngnalals s a3a3ay ay frfrom om t't'e e sosomama**  4eurons are lassifie( in t3o 3ays5 aor(ing  4eurons are lassifie( in t3o 3ays5 aor(ing to num)er of its e2tensions an( )ase( on t'e to num)er of its e2tensions an( )ase( on t'e (i

(irerettioion n of of trtransansmimissssioion n of of ininfoformrmatatioion*n* $'ere are t'ree types of neurons aor(ing to $'ere are t'ree types of neurons aor(ing to t'e num)er of e2tensions* First, is a neuron t'e num)er of e2tensions* First, is a neuron t'at is ompose( of a s'ort e2tension (i#i(e( t'at is ompose( of a s'ort e2tension (i#i(e( iinntto o tt33o o ))rraann''ees s 33iitt' ' oonne e ))rraann'' funtioning as an a2on an( t'e seon( )ran' funtioning as an a2on an( t'e seon( )ran' as a (en(rite* $'is type of neuron is alle( as a (en(rite* $'is type of neuron is alle(  pseu(ounipolar

 pseu(ounipolar neurons* neurons* !eon(, !eon(, is is a a neuronneuron t'at ontains se#eral (en(rites ra(iating from t'at ontains se#eral (en(rites ra(iating from t'e soma toget'er 3it' a single long a2on* t'e soma toget'er 3it' a single long a2on* $'is neuron is terme( as multipolar neurons* $'is neuron is terme( as multipolar neurons* $'e t'ir( an( last type of neuron aor(ing to $'e t'ir( an( last type of neuron aor(ing to t'

t'e e amamouount nt of of e2e2tetensnsioions ns arare e t't'e e )i)ipopolalar r  neu

neuroronsns* * $'i$'is s neneururon on 'a'as s t3t3o o e2e2tetensnsioionsns e2

e2'i'i)i)ititing ng sisimimilalar r lelengngt't's* s* $'$'e e seseoon(n( la

(iretion of information transmission* "n(er  t'is type are sensory neurons, motor neurons an( interneurons* !ensory neurons reei#e signals from sensory organs an( transmit t'ese signals t'roug' t'e a2on into t'e entral ner#ous system* 6n t'e ot'er 'an(, motor  neurons on(ut signals7information from t'e orte2 into t'e spinal or( an( e#entually to t'e musles7musle ells* Finally, interneurons onnet se#eral neurons in t'e entral ner#ous system*

Aor(ing to &a2inos - !tone ./8.1, neurons reei#e impulse an( transmits it to t'e follo3ing neuron t'us in(iating t'at ner#e impulses funtion as a 'ain reation* A neuron is polarize( first )efore it )eomes stimulate(* +n t'e polarization state resting mem)rane potential1, t'e neuron 'as a  positi#e eletrial 'arge outsi(e of t'e mem)rane (ue to t'e e2ess of so(ium ions an( a negati#e eletrial 'arge insi(e t'e mem)rane )eause of t'e potassium ions  present* Aor(ing to 9e#itan - Kazmare: 

./8;1, at (epolarization, t'e 4a ions goes into t'e ell* After (epolarization, repolarization ours 3'en t'e K ions mo#e (eparts t'e ell* Furt'er K ions 3oul( mo#e out of t'e ell 'yperpolarizing t'e mem)rane* After 'yperpolarization, t'e K ions an( 4a ions 3ill go )a: to its original state e2'i)iting again t'e resting mem)rane

 potential*

$'is sequene (emonstrates t'e ation  potential stimulation* Ation potentials are signifiant eletrial signal t'at allo3s ommuniation among neurons use( )y t'e ner#ous system in relaying information &almer - !tuart, .//01* +t is pro(ue( )y t'e opening an( losing of #oltage<gate( so(ium 'annels an( #oltage<gate( potassium 'annels Cal(3ell, .//=1* $ransfer of  information is generate( as ation potentials mo#e along a2ons* E#ery ner#e is ompose( of numerous a2ons t'at are parallel to one anot'er* >'en t'e stimulation gi#en to a ner#e is large, more a2ons respon( an( a ompoun( ation potential is pro(ue(* +t is t'e summation of all t'e a2ons respon(ing to t'e stimulus )ut it is limite( )eause of t'e restrite( num)er of a2ons per neuron* During stimulation, t'e 4a 'annels are opene( an( inati#ate(* $'is inati#ation of  #oltage<gate( so(ium 'annels for 8<. milliseon(s pre#ents t'e entry of so(ium ions* +nati#ation 3ill ontinue an( (uring t'is time, ation potentials are not generate( an( annot pass t'roug'* $'is is alle( t'e a)solute refratory perio(* &otassium 'annels are responsi)le in 'elping t'e mem)rane to go )a: to its resting mem)rane  potential* After t'e a)solute refratory perio(,  4a 'annels t'at 'a#e reo#ere( from t'e

 pre#ious stimulation, s stronger stimulus is t'en applie( to generate a seon( ation  potential* $'is perio( requires a stronger 

stimulus in or(er to generate an ation  potential an( is alle( relati#e refratory  perio(* Ation potentials tra#el t'roug' a2ons qui:ly in or(er to pro(ue a qui:  response* A2ons are o#ere( 3it' myelin s'eat's t'at inreases t'e rate of on(ution on(ution #eloity1* $'e (iameter of an a2on is also a fator in (etermining t'e on(ution #eloity* $'is e2erise aims to (etermine t'e t'res'ol( #oltage, CA&, an( on(ution #eloity of a ner#e*

II. #etho!ology

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

Set"p an! calibration of e&"ipment

+n setting up an( ali)rating t'e equipment, re( an( )la: alligator lips 3ere onnete( /*; apart1 to t'e t3o metal rungs on opposites of t'e M9$68.7B 4er#e )at'* $'e re( positi#e an( )la: negati#e B4C onnetor on &o3er 9a) 3as t'enonnete( to t'e positi#e an( negati#e analog output onnetor, respeti#ely* After3ar(s, re( an(  )la: lea( from t'e first reor(ing eletro(e 3ere onnete( to t3o of t'e metal rungs of  t'e M99$/8.7B 4er#e Bat' 3'ile t'e ?<pin  po( onnetor to t'e po( port on +nput 8 of 

t'e &o3er 9a)* !ame proe(ure 3as (one for  t'e seon( reor(ing eletro(e, e2ept t'e alligator lips 3ere plae( furt'er a3ay from t'e stimulus eletro(e*

Moistene( filter paper strip 3it' Ringer@s solution 3as put o#er t'e 3ires in t'e ner#e )at' to test its onneti#ity* &o3er9a) 3as turne( on an( 9a) C'art or  !ope */1 3as laun'e( follo3e( )y E2periments Gallery to open CA& !et C'art* From t'e 9a) C'art appliation 3in(o3, Maro menu 3as selete( an( t'e $est

Connetion )utton 'art* $'is automatially reor(e( t'e (ata for 8 seon(* A series of  stimulus pulses 3ere seen from t'e monitor  t'is in(iates t'at onnetions are 3or:ing an( rea(y to )e use1* After (oing all of t'is, a siati ner#e 3as arefully isolate(, 3it'out grasping it 3it' foreps, 3as lai( aross t'e 3ire eletro(es, ma:ing it sure t'at it is onnete( 3it' t'e ati#e onnetions*

A$'$ hreshol! voltage an! maximal %AP amplit"!e

+n t'is setion ner#e 3ere gi#en a series of eletrial stimuli, ea' 3it' inreasing amplitu(e* After3ar(s, t'res'ol( #oltage an( #oltage require( for ma2imum CA& amplitu(e for t'e ner#e 3ere alulate(* From t'e C'art 3in(o3, Maro $'res'ol( #oltage 3as li:e(* $'is automatially stimulate( t'e ner#e an( reor( it for 8*8 s*

>a#eform ursor 3as use( to measure t'e CA& amplitu(e at ea' stimulus #oltage* $'e stimulus le#el 3ere t'e first CA& 3as seen an( t'e ma2imum CA& amplitu(e 3as also note(*

A$2$ Refractory Perio!

+n t'is part of e2periment, &o3er9a) stimulates t'e ner#e 3it' series of pulses 3it' a (ereasing inter#al* +n or(er to (o t'is, minimum stimulus #oltage require( to (ra3 a ma2imal CA& from t'e ner#e mV1 3ere (etermine(* 4e2t, from t'e 9a)C'art 3in(o3, Maro Refratory mV 3as selete(, 3it' t'e #oltage nearest to t'e minimum stimulus #oltage* >it' a 8; (ata  )lo:s an( 8/ milliseon(s (uration, results 3ere reor(e( an( analyze( )ase( from t'e follo3ing $3o CA&@s reor(e( in CA&8 in ea' )lo: of (ata reor(e( in &art . 3ere selete(* oom 3in(o3 3as opene( an( (ata 3as e2amine( using >a#eform Cursor* Amplitu(e for seon( CA& in ta)le  an( stimulus inter#als 3as reor(e(* $'e relati#e an( a)solute refratory perio( 3ere elui(ate(, )y (etermining t'e stimulus inter#al 3'ere t'e amplitu(e of t'e seon( CA& first s'o3s a (erease( an( stimulus inter#al 3'ere t'e seon( CA& ompletely (isappears, respeti#ely*

A$$ Nerve %on!"ction *elocity

A ruler 3as use( to (etermine t'e (istane  )et3een t'e )la: negati#e lea(s of ea' t'e

t3o reor(ing eletro(es* From t'e C'art 3in(o3, Maro Con(ution Veloity 3as selete(5 t'is reor(s a )lo: of (ata in t3o 'annels for 8/ milliseon(s* $'e (ata 3ere t'en reor(e( an( analyze( )y alulating t'e on(ution #eloity*

A seletion 3as ma(e 3'i' inlu(es t'e first CA&* From t'e oom 3in(o3, Mar:er an( >a#eform Cursor 3as use( to (etermine t'e time inter#al for t'e CA& to tra#e5 )et3een t'e t3o reor(ing eletro(es* After t'at, C'annel 8 an( 'annel . 3as selete( an( a mar:er 3as plae( on t'e first CA& pea: an( t'e 3a#eform ursor o#er t'e seon( CA&  pea:, respeti#ely* $ime (ifferential △t1 3as

rea( an( reor(e(* $o get t'e on(ution #eloity, measurements for t'e (istane  )et3een t'e t3o reor(ing eletro(es an( t'e

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

III. Res"lts an! +isc"ssion

A$'$ +etermination of threshol! voltage an! maxim"m %ompo"n! Action

Potential

$'e first part of t'e e2periment aims to (etermine t'e t'res'ol( #oltage an( ma2imum CA& amplitu(e* As seen in Figure 8, t'e CA& amplitu(e faile( to rise a)o#e /mV 3'en t'e stimulus amplitu(e is less t'an

;/mV* +t 3as only 3'en ;/mV 3as applie( t'at t'e CA& amplitu(e starte( to rise* $'e CA& amplitu(e ontinue( to rise as t'e stimulus amplitu(e 3as inrease(*

$'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 stimulus amplitu(e no longer 3ent o#er t'e ma2imum CA& amplitu(e #alue*

 4er#es are go#erne( )y t'e all<or not'ing la3 3'erein t'ere is no me(ian ation potential* A stimulus 3ill eit'er ati#ate t'e ner#e or it 3ill not* As seen in figure 8, t'e ner#e only  )egan on(uting ation potentials a)o#e

;/mV* More an( more a2ons 3ere ati#ate( as t'e strengt' of t'e stimulus inrease(* Ho3e#er, at 8/ mV, all of t'e a2ons 3it'in t'e ner#e 3ere alrea(y ati#ate(* $'us CA& (i( not rise a)o#e *;/mV e#en if t'e stimulus amplitu(e 3as inrease(* $'us, t'e t'res'ol( #oltage of t'e ner#e is ;/mV 3'ile t'e ma2imum CA& is *;/mV*

A$2$ +etermination of refractory perio!

$a)le 8* CA& amplitu(e #ersus stimulus intensity Stimulus Interval (ms) Amplitude of Second CAP 4 -0.050 mV 3.5 -0.150mV 3.0 -0.225mV 2.5 -0.050mV 2.0 0.000 mV 1.9 -0.05mV 1.8 -0.02mV 1.7 -1.50mV 1.6 -2.50mV 1.5 -2.50mV 1.4 -0.025mV 1.3 -0.075mV 1.2 -0.025mV 1.0 -0.200mV

$a)le 8 s'o3s t'e results o)taine( in t'e sai( su)setion of t'e e2periment* Ho3e#er, t'e results o)taine( faile( to  pro(ue feasi)le an( i(eal (ata* Errors for 

t'is may inlu(e mis'an(ling or (amage to t'e ner#e or in t'e usage of t'e apparatus* Hene, to ompensate for t'ese results, it 3as

also (one in &'ysioE2 =*/*

$a)le .* Results from &'ysioE2

$'e t'res'ol( #oltage of t'e ner#euse( in &'ysioE2 =*/ 3as set at ./mV* >it' an inter#al of .;/mse an( 8.;mse, a seon( ation potential 3as pro(ue(* Ho3e#er, 3'en t'e inter#al 3as lo3ere( to 0/mse, a seon( ation potential 3as not o)ser#e(* +t 3as only 3'en t'e stimulus #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

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

$'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 e2amine( ner#e is *;mse* $'e ner#e nee(s more t'an *;mse for t'e 4a 'annels to return to a resting potential* $'e relati#e refratory perio( imme(iately follo3s t'e a)solute refratory perio(* +n t'e relati#e refratory perio(, a seon( ation potential an )e pro(ue( at a 'ig'er 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 /*8m1 )ut sine t'e ta)le )elo3 is in m, /*8 is on#erte( to 8/m* $'e time inter#al  )et3een CA&8 an( CA&. is /*/s )ut sine t'e ta)le )elo3 is in ms, /*/ is on#erte( to /ms* $'en using t'e formula

$a)le * Calulation of Con(ution Veloity

IV. %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

Compoun( Ation &otential  Refratory  perio(*

n*(*1* Retrie#e( from

'ttp77333*me(iine*mgill*a7p'ysio 7#la)7CA&7refrat*'tm

Goo(man, B* &*, Harper, C* M*, - Boon, A* J* .//=1* &rolonge( ompoun( musle ation potential (uration in ritial illness myopat'y* Musle - 4er#e Musle 4er#e, I/01, 8/I/<8/I.*

 4euronal Ation &otential  +mportant features

of t'e neuronal ation potential ./8I1* Retrie#e( from

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