Lab 7 The Muscular System
e e e e BIO201L
(LAB 7) Straighter line anatomy and physiology 1 lab
BIO201L The muscular system worksheet 2025
Guaranteed Pass
StudenteName:eClickehereetoeenteretext.
AccesseCodee(locatedeonetheelideofeyourelabekit):eClickehereetoeenteretext.
Pre-LabeQuestions
1. Howedoebandingepatternsechangeewheneaemuscleecontracts?
Wheneaemuscleecontracts,etheebandingepatternsewithinetheemuscleechangeedueetoetheeslidingefila
mentetheoryeofemuscleecontraction.eThisetheoryesuggestsethatemuscleecontractioneoccursewhenethi
nefilamentse(actin)eslideeoverethickefilamentse(myosin),eresultingeinetheeoverlappingeofetheseefilame
ntseandeshorteningeofetheesarcomeres,ewhicheareetheebasicecontractileeunitseofetheemuscle.eAseaer
esult,etheedarkeAebands,ewhicheconsisteofeoverlappingemyosinefilaments,estayerelativelyeconstantein
elength,ewhileetheelighteIebands,ewhichecontaineonlyeactinefilaments,eshorten.eTheeHezone,elocatedei
netheemiddleeofetheeAeband,ealsoenarrowseoredisappearsealtogether.eTheseechangeseinetheebandinge
patternsereflectetheemoleculareeventsethateoccureduringemuscleecontraction.
2. Whateisetheedifferenceebetweeneaemuscleeorgan,eaemuscleefiber,emyofibrileandeae
myofilament?
aemuscleeorganerefersetoetheeentireestructureecomposedeofemuscleetissue,econnectiveetissue,eblo
odevessels,eandenerves,ewhicheworketogetheretoeproduceemovement.eAemuscleefiber,ealsoeknowne
aseaemuscleecell,eiseaesingleeelongatedecellewithinetheemuscleeorganethatecontainsemyofibrils.eMyo
fibrilseareecylindricalestructuresewithinemuscleefibersecomposedeoferepeatingeunitsecalledesarcom
eres,ewhicheareeresponsibleeforemuscleecontraction.eFinally,emyofilamentseareetheeproteinefilamen
tsefoundewithinetheesarcomeres,ewithetwoemainetypes:ethickefilamentse(myosin)eandethinefilaments
e(actin).eMyofilamentseinteractewitheeacheotheretoegenerateemuscleecontractionebyetheeslidingefila
mentetheory.eInesummary,eaemuscleeorganecontainsemuscleefibers,ewhichehouseemyofibrilsethatear
eemadeeupeofemyofilamentseresponsibleeforemuscleecontraction.
3. Outlineetheemolecularemechanismeforeskeletalemuscleecontraction.eAtewhatepointeiseATPeusede
andewhy?
Theemolecularemechanismeforeskeletalemuscleecontractioneiseknowneasetheeslidingefilamentetheor
y.eIteinvolvesetheeinteractionebetweenethickefilamentse(myosin)eandethinefilamentse(actin)ewithineth
eesarcomereseofemuscleefibers.eWheneaenerveeimpulseestimulateseaemuscle,ecalciumeionseareerel
eased,ebindingetoeregulatoryeproteinseandeallowingemyosineheadsetoeinteractewitheactin.eThiseform
secross-bridges,eandeATPebindsetoetheemyosineheads,ecausingethemetoedetach
,Lab 7 The Muscular System
e e e e BIO201L
fromeactin.eATPeisethenehydrolyzedeintoeADPeandePie(inorganicephosphate),eprovidingetheeenergyefo
retheemyosineheadsetoecockebackeintoetheirehigh-
energyeposition.eAsetheemyosineheadsereattachetoeactin,etheepowerestrokeeoccurs,epullingetheethine
filamentsetowardsetheecentereofetheesarcomereeandeshorteningetheemuscle.eATPeiseusededuringeth
eedetachmenteofemyosinefromeactineandetheesubsequentecockingeofetheemyosineheads,eprovidinget
heenecessaryeenergyeforetheecontractioneprocessetoecontinue.
4. Explainewhyerigoremortiseoccurs.
Rigoremortiseoccurseafteredeathedueetoeaetemporaryestateeofemuscleestiffnesseanderigidity.eItehapp
ensebecause,eafteredeath,etheeproductioneofeATPeceases,eandetheeavailableeATPeinetheemusclesege
tsedepleted.eIneaenormalefunctioningemuscle,eATPeiserequiredeforetheedetachmenteofemyosineheadse
fromeactineduringetheemuscleerelaxationephase.eHowever,ewithouteATP,ethe
, Lab 7 The Muscular System
e e e e BIO201L
myosineheadseremaineboundetoeactin,eresultingeineaesustainedecontractionestate.eThiseleadsetoethee
characteristicestiffnesseobservedeinerigoremortis.eOveretime,easetheemuscleeproteinsebeginetoedegra
de,erigoremortisegraduallyeresolves.
.
Experimente1:eTendonseandeLigaments
Post-LabeQuestions
1. Labeletheearrowseinetheeslideeimagesebelowebasedeoneyoureobservationsefromethee
experiment.
A-eChondrocytes
B-ecollagen
C-ecollagenefibre
D-eskeletalemuscleefibre
E-enuclei
F-ecollagenefibre
e e e e BIO201L
(LAB 7) Straighter line anatomy and physiology 1 lab
BIO201L The muscular system worksheet 2025
Guaranteed Pass
StudenteName:eClickehereetoeenteretext.
AccesseCodee(locatedeonetheelideofeyourelabekit):eClickehereetoeenteretext.
Pre-LabeQuestions
1. Howedoebandingepatternsechangeewheneaemuscleecontracts?
Wheneaemuscleecontracts,etheebandingepatternsewithinetheemuscleechangeedueetoetheeslidingefila
mentetheoryeofemuscleecontraction.eThisetheoryesuggestsethatemuscleecontractioneoccursewhenethi
nefilamentse(actin)eslideeoverethickefilamentse(myosin),eresultingeinetheeoverlappingeofetheseefilame
ntseandeshorteningeofetheesarcomeres,ewhicheareetheebasicecontractileeunitseofetheemuscle.eAseaer
esult,etheedarkeAebands,ewhicheconsisteofeoverlappingemyosinefilaments,estayerelativelyeconstantein
elength,ewhileetheelighteIebands,ewhichecontaineonlyeactinefilaments,eshorten.eTheeHezone,elocatedei
netheemiddleeofetheeAeband,ealsoenarrowseoredisappearsealtogether.eTheseechangeseinetheebandinge
patternsereflectetheemoleculareeventsethateoccureduringemuscleecontraction.
2. Whateisetheedifferenceebetweeneaemuscleeorgan,eaemuscleefiber,emyofibrileandeae
myofilament?
aemuscleeorganerefersetoetheeentireestructureecomposedeofemuscleetissue,econnectiveetissue,eblo
odevessels,eandenerves,ewhicheworketogetheretoeproduceemovement.eAemuscleefiber,ealsoeknowne
aseaemuscleecell,eiseaesingleeelongatedecellewithinetheemuscleeorganethatecontainsemyofibrils.eMyo
fibrilseareecylindricalestructuresewithinemuscleefibersecomposedeoferepeatingeunitsecalledesarcom
eres,ewhicheareeresponsibleeforemuscleecontraction.eFinally,emyofilamentseareetheeproteinefilamen
tsefoundewithinetheesarcomeres,ewithetwoemainetypes:ethickefilamentse(myosin)eandethinefilaments
e(actin).eMyofilamentseinteractewitheeacheotheretoegenerateemuscleecontractionebyetheeslidingefila
mentetheory.eInesummary,eaemuscleeorganecontainsemuscleefibers,ewhichehouseemyofibrilsethatear
eemadeeupeofemyofilamentseresponsibleeforemuscleecontraction.
3. Outlineetheemolecularemechanismeforeskeletalemuscleecontraction.eAtewhatepointeiseATPeusede
andewhy?
Theemolecularemechanismeforeskeletalemuscleecontractioneiseknowneasetheeslidingefilamentetheor
y.eIteinvolvesetheeinteractionebetweenethickefilamentse(myosin)eandethinefilamentse(actin)ewithineth
eesarcomereseofemuscleefibers.eWheneaenerveeimpulseestimulateseaemuscle,ecalciumeionseareerel
eased,ebindingetoeregulatoryeproteinseandeallowingemyosineheadsetoeinteractewitheactin.eThiseform
secross-bridges,eandeATPebindsetoetheemyosineheads,ecausingethemetoedetach
,Lab 7 The Muscular System
e e e e BIO201L
fromeactin.eATPeisethenehydrolyzedeintoeADPeandePie(inorganicephosphate),eprovidingetheeenergyefo
retheemyosineheadsetoecockebackeintoetheirehigh-
energyeposition.eAsetheemyosineheadsereattachetoeactin,etheepowerestrokeeoccurs,epullingetheethine
filamentsetowardsetheecentereofetheesarcomereeandeshorteningetheemuscle.eATPeiseusededuringeth
eedetachmenteofemyosinefromeactineandetheesubsequentecockingeofetheemyosineheads,eprovidinget
heenecessaryeenergyeforetheecontractioneprocessetoecontinue.
4. Explainewhyerigoremortiseoccurs.
Rigoremortiseoccurseafteredeathedueetoeaetemporaryestateeofemuscleestiffnesseanderigidity.eItehapp
ensebecause,eafteredeath,etheeproductioneofeATPeceases,eandetheeavailableeATPeinetheemusclesege
tsedepleted.eIneaenormalefunctioningemuscle,eATPeiserequiredeforetheedetachmenteofemyosineheadse
fromeactineduringetheemuscleerelaxationephase.eHowever,ewithouteATP,ethe
, Lab 7 The Muscular System
e e e e BIO201L
myosineheadseremaineboundetoeactin,eresultingeineaesustainedecontractionestate.eThiseleadsetoethee
characteristicestiffnesseobservedeinerigoremortis.eOveretime,easetheemuscleeproteinsebeginetoedegra
de,erigoremortisegraduallyeresolves.
.
Experimente1:eTendonseandeLigaments
Post-LabeQuestions
1. Labeletheearrowseinetheeslideeimagesebelowebasedeoneyoureobservationsefromethee
experiment.
A-eChondrocytes
B-ecollagen
C-ecollagenefibre
D-eskeletalemuscleefibre
E-enuclei
F-ecollagenefibre
