Psl300 Muscle Physiology Questions And Correct Answers

PSL300 MUSCLE PHYSIOLOGY
QUESTIONS AND CORRECT ANSWERS
MuscleA2classificationsA2-A2Ans--Skeletal,A2smooth,A2cardiacA2muscle

SkeletalA2muscleA2fibersA2-A2Ans--
Large,A2multinucleateA2cellsA2thatA2appearA2stripedA2orA2striatedA2underA2theA2microscope
A2(striation).


CardiacA2muscleA2fibersA2-A2Ans--StriatedA2butA2Smaller,A2branched,A2andA2uninucleate.

IntercalatedA2diskA2(cardiacA2muscle)A2-A2Ans--
CellsA2areA2joinedA2inA2seriesA2byA2thatA2junction

smoothA2muscleA2-A2Ans--
FibersA2areA2smallA2andA2lackA2striation,A2muscleA2aroundA2stomachA2andA2constructA2int
ernalA2organ.

skeletalA2muscleA2containA2-A2Ans---activationA2byA2theA2somaticA2nervousA2system
-A2motorA2neurons
-NMJ
-contractileA2filamentsA2inA2sarcomeres;A2striated
-wellA2developedA2sarcoplasmicA2reticulumA2(SR)

AA2motorA2unitA2consistsA2ofA2-A2Ans--
aA2motorA2neuronA2andA2theA2muscleA2fibersA2itA2innervates

neuro-muscularA2junctionA2(NMJ)A2-A2Ans--
AA2synapseA2betweenA2theA2axonA2terminalsA2ofA2aA2motorA2neuronA2andA2theA2sarcolem
maA2ofA2aA2muscleA2fiberA2(cell),A2chemicalA2signaling

sarcroplasmicA2reticulumA2(SR)A2-A2Ans--

muscleA2fascicleA2-A2Ans--bundleA2ofA2muscleA2fibersA2wrapA2aroundA2andA2wiring

MuscleA2consistsA2ofA2-A2Ans--
MuscleA2fibersA2extendedA2lengthA2fromA2tendonA2toA2tendons,A2connectiveA2tissue,A2nerv
eA2andA2bloodA2vessels.

MyofibrilsA2-A2Ans--
ThickA2andA2thinA2filamentsA2structuresA2thatA2makeA2upA2muscleA2fibers,A2surroundedA2b
yA2sarcoplasmicA2reticulumA2andA2T-tubes

muscleA2fiberA2-A2Ans--aA2singleA2muscleA2cellA2withA2multinuclei

, sarcolemma,A2T-tubules,A2sarcoplasmicA2reticulumA2-A2Ans--
ContractionA2ofA2skeletalA2andA2cardiacA2muscleA2isA2initiatedA2whenA2aA2waveA2ofA2electri
calA2depolarizationA2spreadsA2overA2theA2plasmaA2membrane,A2whichA2inA2muscleA2cellsA
2isA2calledA2theA2_____.A2ThisA2waveA2ofA2electricalA2depolarizationA2penetratesA2intoA2the
A2interiorA2ofA2theA2muscleA2cellA2viaA2invaginationsA2calledA2_____,A2leadingA2toA2theA2rel
easeA2ofA2calciumA2ionsA2fromA2theA2______A2.

TheA2muscleA2fibersA2ofA2aA2motorA2unitA2-A2Ans--AllA2contractA2together

TheA2smoothnessA2andA2precisionA2ofA2movementA2dependsA2onA2-A2Ans--
theA2numberA2andA2timingA2ofA2motorA2unitsA2thatA2areA2activated

muscleA2contractionA2stepsA2-A2Ans--
1)A2MotorA2neuronA2releasesA2acetylcholineA2intoA2theA2neuromuscularA2junctionA2andA2c
ausesA2theA2depolarizationA2ofA2theA2sarcolemma.

2)A2DepolarizationA2spreadsA2downA2theA2sarcolemmaA2toA2theA2T-
tubules,A2triggeringA2theA2releaseA2ofA2Ca2+A2ions.

3)A2Ca2+A2bindsA2toA2troponin,A2causingA2aA2shiftA2inA2tropomyosinA2andA2exposureA2ofA2t
heA2myosin-bindingA2siteA2onA2theA2actinA2filament.

4)A2ShorteningA2ofA2theA2sarcomereA2occursA2asA2theA2myosinA2headA2bindsA2toA2theA2exp
osedA2sitesA2ofA2actin,A2formingA2aA2cross-
bridgeA2andA2pullingA2theA2actinA2filamentA2alongA2theA2thickA2filament,A2resultingA2inA2con
traction.

5)A2MuscleA2relaxesA2whenA2acetylcholineA2isA2degradedA2byA2acetylcholineA2esteraseA2a
ndA2theA2allowingA2Ca2+A2isA2broughtA2backA2intoA2theA2SR.A2ATPA2bindsA2toA2myosinA2he
ad,A2allowingA2itA2toA2relaxA2fromA2actin.

OneA2muscleA2mayA2haveA2many________,A2theA2muscleA2fiberA2ofA2aA2motorA2unitA2areA
2______.A2-A2Ans--MotorA2unitsA2ofA2differentA2fiberA2types;A2allA2ofA2theA2sameA2type


ThereA2areA23A2broadA2categoriesA2ofA2muscleA2fiber,A2andA2henceA2________.A2TheseA2c
ategoriesA2areA2basedA2uponA2theirA2_______.A2-A2Ans--
3A2broadA2categoriesA2ofA2motorA2units;A2histochemicalA2characteristic.

neuromuscularA2junctionA2(NMJ)A2propertiesA2-A2Ans---
ActivatedA2byA2somaticA2nervousA2systemA2
-
A2consistA2ofA2axonA2terminals,A2motorA2endA2platesA2onA2theA2muscleA2membraneA2andA2
SchwannA2cellA2sheaths