Physiology 2

PHYSIOLOGY Pre-Boards 2006-2007 Muscle/Vision  Neurotransitter  Neurotransitter in!ol!ed in s"eletal uscle uscle contraction a# Acetylcholine c# $%ine%&rine  '# Nore%ine%&rine d# G(B( )alciu in t&e cell o* soot& uscle 'inds +it& a# ,ro%onin ) c. Early relaxation  '# Late relaation relaation (.P P &ead o* uscle --- bending (t t&e onset o* uscle contraction t&e initial source o* con*oration --- ATP for creatinine phosphate )ross 'rid1e lin"a1e 'et+een actin and osin is not %ossi'le +&en s"eletal uscle is at rest due to --- interference by tropomyosin molecule In ecitation contraction cou%lin1 +&at iediatel *ollo+s de%olari3ation o* trans!erse tu'ule --- diffusion of Ca ion from sarcoplasmic reticulum to myofilaments .urin1 s"eletal uscle t&e a# H 3one 'ecoes s&orter  '# ( 'and 'and decrease in +idt& +idt&

c# I 'and reains unc&an1ed d. both a and c

,ro%oosin a. prevents prevents binding of actin actin & myosin myosin when when muscle muscle is at rest rest b. is a %rotein o* t&in o*i'ril

c# does not 'ind to )a d# all o* t&e a'o!e

4or" 4or" %er*orance is ne!er seen +&en t&e uscle is doin1 a# concentric c. isometric contraction  '# eccentric d# a and ' ,etanus ,etanus is o'ser!e in s"eletal uscle i* e%osed to --- increase stimulation intensity 5uantal suation --- also known as graded multiple motor unit summation due to recruitment of motor unit ,rue o* s%at&etic ner!ous sste ece%t a# lon1er %ost1an1lionic  '# arise *ro t&oracic t&oracic to lu'ar lu'ar ner!es

c# ca cata'olic in nature d. discrete and localied effect

)enters *or re1ulation o* cardio!ascular acti!it and *or res%iration are located in t&e a. s%inal coard c# cere'ral corte d# li'ic sste b. medu medull lla a oblo oblong ngat ata a (ll o* t&e *ollo+in1 &a!e nicotinic rece%tors ece%t a. radi radial al mus muscl clee of the the iris iris c# s"eletal uscle d# soot& uscle b. s+eat 1lands Bot& %aras%at&etic and s%at&etic %re1an1lionic *i'ers release a. Acetylch lcholine line c# Nore%ine%&rine d# L-do%aine b. $%ine%&rine 4&ic& o* t&e *ollo+in1 is/are not c&oliner1ic a# %re1an1lionic s%at&etic *i'er  '# all %ost1an1lionic %ost1an1lionic %aras%at&etic %aras%at&etic *i'er 

c# %re1an1lionic %aras%at&etic *i'er   d. most preganglionic preganglionic sympathetic fiber

(tro%ine 'loc"s t&e uscarinic rece%tor +it& a# soatic neurouscular unction  '# c&oliner1ic s%at&etic neuroe**ector neuroe**ector unction unction

c# %a % aras%at&etic neuroe**ector   d. both b and c

4&ic& o* t&e *ollo+in1 stateents re1ardin1 acetlc&oline acetlc&oline e**ect is incorrect a. decrease *r *reuenc o* S( node disc&ar1e c# decrease %a%illar diaeter  d# increase sali!ar sali!ar secretion secretion b. decr decrea ease se intes intesti tina nall motili motility ty ,&e lar1est co%onent o* t&e %aras%at&etic %aras%at&etic di!ision is +&at )N8 a. vagus c# *acial d# 1losso%&arn1eal b. occulootor ,&e %aras%at&etic ner!e a. give give ris risee to to a more more loca locali lied ed  '# are deri!ed *ro *ro t&e t&oracolu'ar t&oracolu'ar di!ision o* t&e t&e s%inal cord c# &as t&e adrena adrenall edul edulla la as its its 1an1 1an1lia lia d# &as a s&or s&ortt %re %re1an 1an1li 1lioni onicc *i'e *i'er  r  ,&e ecitator e**ects o* t&e s%at&etic di!ision are seen in all o* t&e *ollo+in1 ece%t a# dil dilator ator %u%i %u%illlae lae c. gastrointestinal tract  '# cardiac uscle d# cutaneous 'lood !essels !essels

(ll !isceral e**ector cells are duall inner!ated ece%t a# s+eat 1lands c# sali!ar 1lands  '#  %ilootor uscle d. a and b  Not a s%at&etic 1an1lion a. terminal ganglion b. esenteric 1an1lion

c# adrenal edulla d# 'ot& a and c

.MG %otentiates adrener1ic e**ects a# t&ose %re!ent reu%ta"e and N$ ' t&e %ost1an1lionic *i'ers  '# t&ose t&at in&i'it M(O c# t&ose not interact +it& 'eta rece%tor  d. all of the above .ru1s t&at interact t&e uscarinic rece%tors initiatin1 (c& a. potentiates cholinergic effect c# 'loc"s adrener1ic e**ect b.  'loc"s c&oliner1ic e**ect d# %otentiates s%at&etic e**ect )N6 inner!ates t&e ee uscle t&at +ill o!e t&e ee a. in+ard c# do+n and out b. outward d# u% and out Paras%at&etic e**ect o* t&e ee include t&e *ollo+in1 ece%t --- contraction o* t&e radial uscle 9e*ractin1 edia o* t&e ee include t&e *ollo+in1 ece%t a# cornea c. pupil  '# lens d# aueous &uor  ,&ese neurons connect t&e ee %&otorece%tors +it& one anot&er and %ro!ide t&e lateral in&i'it ec&anis in !isual neural circuitr a.  'i%olar c# aacrine cells b. horiontal cells d# 1an1lion cells O%tic c&ias ade u% o*  a. te%oral *i'er *or 'ot& ees b. nasal fiber for both eyes

c# nasal *i'er *or t&e 9 ee and te%oral *i'er *or t&e L ee d# nasal *i'er *or t&e L ee and te%oral *i'er *or t&e 9 ee

Visual circuitr %resent in a# rods and cones  '# 'i%olar cells

c# &ori3ontal cells d. all of the above

Mostl %resent in cones --- color !ision Hi1&est !elocit transittin1 cells a. 4 b. :

c. ! d# all o* t&e a'o!e

Ma1nocellular %at&+a --- movement 9i1&t o%tic radiation --- right nasal left temporal Point in t&e lens +&ere li1&t ras %ass +it&out re*raction --- nodal point ,&e re*racti!e %o+er o* t&e lens --- increase with an increasing in the curvature of the lens (ccoodation *or near !ision in!ol!es --- contraction of the ciliary muscle and decrease tension in the l ens ligament 4&ic& is not an o%tical de*ect o* an eetro%ic ee --- astigmatism In &%ero%ia --- retina is reached by the light rays before they come into focus In %res'o%ia --- decrease in amplitude of accommodation  Not a c&aracteristic o* rods --- they have higher threshold for light Portion o* structure o* t&e %&otorece%tors contains t&e li1&t sensiti!e %&otoc&eical su'stance --- outer segment In dar" ada%tation true is --- resynthesis constriction )olor 'lindness u%on +a!elen1t& o* li1&t --- hue Blindness to red decrease %erce%tion to 1reen noral to 'lue --- protanopia Lesion to o%tic tract --- right homonymous hemianopsia Lesion to o%tic c&ias --- bilateral hemianopsia Sta'ili3e restin1 e'rane %otential o* Na --- increase extracellular Ca" concentration

Saltator conduction is %ossi'le 'ecause o* --- myelination of the fiber Visual accoodation in!ol!es +&ic& o* t&e ec&anis a. relaation o* ciliar uscle b. increase in the refractive power of the lens

c# t&e lens is &eld under tension d# t&e lens is %ulled into *lattened s&a%e

,&e etraocular uscle o!es ee'all do+n+ard lateral --- superior obli#ue ,&e onl retinal neural cells t&at 1enerate action %otential --- ganglion cells 4&ic& o* t&e *ollo+in1 re1ion o* t&e ee &as t&e 1reatest concentration o* cones --- foveal region ,&e 'lind s%ot o* t&e ee a# contain t&e rod onl  '# &as 1reatest concentration o* cones

c# it is t&e re1ion +it& lo+est !isual acuit d. is insensitive to light

,&e %art res%onse accoodation con!er1ence o* !isual aes and %a%illar contraction is called a# near %oint c. near response  '# li1&t re*le d# ada%tation Most coon o* t&e *ollo+in1 re*racti!e edia o* t&e ee ece%t a# cornea c. pupil  '# lens d# aueous &uor  Blind s%ot is --- absent in the visual field in binocular vision ,&e laer %re!ents t&e re*lection o* li1&t ras 'ac" t&rou1& t&e retina --- pigment epithelium  Neural cells t&at connect one 1an1lion +it& anot&er 1an1lion cells --- amacrine cells Vitain ( de*icienc +ill lead to --- night blindness )orrect a'out color 'lindness --- autosomal recessive disorder ,%e o* rece%tor does e%ine%&rine stiulate in aortic !eins to %roduce !enous constriction --- alpha $  Ner!e *i'ers t&at conducts *ast %ain --- type A delta (%%lication o* a su%raaial stiulus a*ter aiu stiulation +ill ; t&e si3e o* t&e action %otential o* %eri%&eral ner!es --- no effect Pacea"er cells are %resent in --- smooth and cardiac ,-tu'ule sste o* cardiac uscle is located --- % discs  Nu'er o* osin 'indin1 site e%osed +&en tro%oosin is dis%laced ---  ,%es o* uscle *i'er contri'ute lar1e aount o* o1lo'in a# t%e I d. a and b  '# t%e II( e# ' and c c# t%e IIB )a is %u%ed acti!el 'ac" to t&e sarco%lasic reticulu t&rou1& a.  Na-< (,Pase %u% c# Na-2Na (,Pase %u% d# =Na-2< (,Pase %u% b. Ca'(g ATPase pump Priar source o* calciu *or initiation o* soot& uscle contraction a# sarco%lasic reticulu c# intracellular calciu  '# itoc&ondria d. extracellular calcium (ll o* t&e *ollo+in1 e!ents occur durin1 t&e latent %&ase o* a uscle t+itc& ece%t --- release of Ca from troponin (%%lin1 se!eral stiuli o* increasin1 intensit --- #uantal summation )&aracteristic o* isotonic contraction --- there is approximation of ends of muscle 4&ic& uscle tension is aial durin1 restin1 len1t& a.  %assi!e tension c# total tension b. active tension d# restin1 tension t&e aons o* t&e cells con!er1e and lea!e t&e ee as t&e o%tic ner!e a# 'i%olar cells c# aacrine cells  '# &ori3ontal cells d. ganglion cells Is res%onsi'le *or *oration o* a odulated neuronal disc&ar1e --- extensor and reflex extension ,&e 1eneration o* rece%tor --- withdrawal reflex Su'stance use to de*icit $PP *or uscle contraction --- tubocurarine

 Nore%ine%&rine as its aor secretion a# adrenal edulla c# postganglionic sympathetic neurons of radial muscle of the iris  '# adrenal corte d# %ost1an1lionic s%at&etic neurons to s+eat 1lands Heaet&oniu dru1 t&at 'loc"s action o* (cetlc&oline on %ost1an1lionic autonoic neuron +&ic& &as restin1 su'ect d# increase arterial %ressure a. decrease &eart rate b. increase heart rate e# %re!ent s"eletal uscle !asodilatation c. disa%%earance o* intestinal resistance Patient &as 'een recei!in1 %&eno'en3aine >(-'loc"in1 a1ent? co%lained o* di33iness and *aintin1 +&ile +al"in1 u% *li1&t o* stairs durin1 &is eercise --- heart rate would increase 4&ic& o* t&e *ollo+in1 is correct a# e%ine%&rine %roduce ore ar"ed increase action %otential t&an nore%ine%&rine  '# norepinephrine produces more marked increase action potential than epinephrine c# nore%ine%&rine &as sae B2 stiulator action as e%ine%&rine d# $%ine%&rine %roduces ore etensi!e !asoconstriction t&an nore%ine%&rine 4&ic& o* t&e *ollo+in1 'est de*ines contraction --- reaction that cause the muscle to pull (n isotonic contraction di**ers *ro an isoetric contraction is t&at isotonic contraction --- muscle uses more increased energy phosphate level ( s"eletal uscle %artici%atin1 in a strenuous eercise di**ers *ro a restin1 s"eletal uscle in t&at t&e eercisin1 usle --exhibits all characteristics )a@@ seuestered ' t&e sarco%lasic reticulu o* s"eletal uscle durin1 t+itc& is directed to a# t&e rate o* tension d# neit&er    '# t&e rate o* (,P &drolsis ' osin e# the rate of relaxation c# 'ot& ,&e di**erence 'et+een slo+ uscle *i'er t+itc& and *ast uscle *i'er t+itc& a# ;;  '# sall uscle *i'ers in eac& otor unit c# &i1&er concentration o* o1lo'in and itoc&ondria d# b and c