![12864_2007_1541_MOESM2_ESM.xls - Springer Static …… · XLS file · Web view · 2016-01-12Troponin T, cardiac muscle (TnTc) (Cardiac muscle troponin T) (cTnT). [Source:Uniprot/SWISSPROT;Acc:P45379]](https://static.fdocuments.in/doc/165x107/5add36ef7f8b9a595f8c937d/1286420071541moesm2esmxls-springer-static-xls-fileweb-view2016-01-12troponin.jpg)
4.1$–$Neuromuscular$Function$ - WordPress.com 04, 2015 · filaments!of!muscle!tissue! Troponin!...
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TOPIC 4 – MOVEMENT ANALYSIS 1 4.1 – Neuromuscular Function 4.1.1 4 Label a diagram of a motor unit TERM FUNCTION STRUCTURE Axon • A nerve fibre o A single process extending from the cell of a neuron Carrying a nerve impulse away from it Dendrite Carries nerve impulses from adjacent neurons into the cell body • One of the shorter branching processes of the cell body of a neuron • All dendrites have synaptic knobs at the ends Which are the ‘connections’ to adjoining nerves Motor Neurone • Transmitting impulses (electrical signals for communication within the body) • From the Central Nervous System (CNS) • Which consists of the brain and spinal cord, to the muscles and glands
Transcript of 4.1$–$Neuromuscular$Function$ - WordPress.com 04, 2015 · filaments!of!muscle!tissue! Troponin!...
TOPIC&4&–&MOVEMENT&ANALYSIS& 1!!
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4.1$–$Neuromuscular$Function$4.1.1$4$Label$a$diagram$of$a$motor$unit!!
!!
!
TERM! FUNCTION! STRUCTURE!Axon! ! •! A!nerve!fibre!
o! A!single!process!extending!
from!the!cell!of!a!neuron!
Carrying!a!nerve!impulse!away!from!it!
Dendrite! Carries!nerve!impulses!from!
adjacent!neurons!into!the!cell!
body!
•! One!of!the!shorter!branching!
processes!of!the!cell!body!of!a!neuron!
•! All!dendrites!have!synaptic!knobs!at!
the!ends! !
Which!are!the!‘connections’!to!adjoining!
nerves!
Motor!Neurone! •! Transmitting!impulses!
(electrical!signals!for!
communication!within!the!
body)!
•! From!the!Central!Nervous!
System!(CNS)!
•! Which!consists!of!the!brain!
and!spinal!cord,!to!the!
muscles!and!glands!
!
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elsewhere!in!the!body!
Myelin!Sheath! •! Protection!of!the!nerve!fibre!
•! Insulation!of!the!nerve!fibre!
•! Increases!the!rate!of!
transmission!of!nerve!
impulses! ! !
•! A!complex!material!formed!of!protein!
and!phospholipid!(fat)!that!is!laid!
down!as!a!sheath!around!the!axons!of!
certain!neurons!
Nerve! •! A!nerve!is!a!bundle!
containing!lots!of!axons!
associated!with!connective!
tissue!and!blood!vessels!
!
Neurone! •! A!cell!specialized!to!transmit!
electrical!nerve!impulses!and!
so!carry!information!from!
one!part!of!the!body!to!
another! ! !
!
Nodes!of!
Ranvier!
•! Allowing!nutrients!and!waste!
products!to!enter!/!leave!the!
neuron!
•! Allowing!nerve!impulses!to!
move!along!the!neuron!
through!a!process!of!
depolarization!and!
repolarization!of!the!nerve!
membrane!
•! Gaps!that!occur!at!regular!intervals!in!
the!myelin!sheath!of!medullated!
nerve!fibres!! !
Synapse! •! An!impulse!causes!the!release!
of!a!neurotransmitter!
•! Diffuses!across!the!gap!and!
triggers!an!electrical!impulse!
in!the!next!neuron! !
•! The!minute!gap!across!which!nerve!
impulses!pass!from!one!neuron!to!the!
next!
!
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TOPIC&4&–&MOVEMENT&ANALYSIS& 3!!
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4.1.2$4$Explain$the$role$of$neurotransmitters$in$stimulating$skeletal$muscle$contraction!!
TERM! DEFINITION!Neurotransmitter! A!chemical!substance!that!is!released!at!the!end!of!a!nerve!fiber!by!the!
arrival!of!a!nerve!impulse!and!by!diffusing!across!the!synapse!or!junction,!
causes!the!transfer!of!the!impulse!to!another!nerve!fiber;!a!muscle!fiber!
Acetylcholine! A!compound!that!occurs!throughout!the!nervous!system,!in!what!it!
functions!as!a!neurotransmitter!
Cholinesterase! An!enzyme,!especially!acetylcholinesterase,!that!hydrolyzes!esters!of!
choline!
!
•! Neurotransmitters!are!chemicals!that!are!used!for!communication!between!a!neuron!at!
the!synapse!and!another!cell!
!
•! Acetylcholine!is!the!primary!neurotransmitter!for!the!motor!neurons!that!innervate!skeletal!muscle!and!for!parasympathetic!neurons!
o! It!is!generally!an!excitatory!neurotransmitter,!but!it!can!be!inhibitory!nerve!
endings;!such!as!the!hear!
!
•! In!biochemistry,!cholinesterase!is!an!enzyme!that!catalyzes!the!hydrolysis!of!the!neurotransmitter!acetylcholine!into!choline!and!acetic!acid,!a!reaction!necessary!to!
allow!a!neuron!to!return!to!its!resting!state!after!activation!
!
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4& TOPIC&4&–&MOVEMENT&ANALYSIS!!
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4.1.3$4$Explain$how$skeletal$muscle$contracts$by$the$sliding$filament$theory!!
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TERM! EXPLANATION!Sliding!
Filament!
Theory!
A!method!by!which!muscles!are!thought!to!contract!
Myofibril! Elongated!contractile!threads!found!in!striated!muscle!cells!
Myofilament! Filaments!of!myofibrils!constructed!from!proteins!
Sarcomere! A!structural!unit!of!a!myofibril!in!striated!muscle,!consisting!of!a!dark!band!
and!the!nearer!half!of!each!adjacent!pale!band!
Actin! A!protein!that!forms!(together!with!myosin)!the!contractile!filaments!of!
muscle!cells,!and!is!also!involved!in!motion!in!other!types!of!cells!
Myosin! A!fibrous!protein!that!forms!(together!with!actin)!the!contractile!filaments!of!
muscle!cells!and!is!also!involved!in!motion!in!other!types!of!cells!
H!Zone!
!
A!Band!
Z!Line!
Tropomyosin! •! A!protein!involved!in!muscle!contraction!
•! It!is!related!to!myosin!and!occurs!together!with!troponin!in!the!thin!
filaments!of!muscle!tissue!
Troponin! •! A!globular!protein!complex!involved!in!muscle!contraction!
•! It!occurs!with!tropomyosin!in!the!thin!filaments!of!muscle!tissue!
Reticulum! •! The!second!stomach!of!a!ruminant,!having!a!honeycomb!like!structure,!
receiving!food!from!the!rumen!and!passing!it!to!the!omasum!
Calcium!Ions!
(Ca2+)!
!
TOPIC&4&–&MOVEMENT&ANALYSIS& 5!!
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!Adenosine!
Triphosphate!
(ATP)!
•! A!compound!consisting!of!an!adenosine!molecule!bonded!to!three!
phosphate!groups,!present!in!all!living!tissue!
o! The!breakage!of!one!phosphate!linkage!(to!form!adenosine!
diphosphate,!ADP!)!provides!energy!for!physiological!processes!
such!as!muscular!contraction!
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MUSCLE$CONTRACTION!!
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MECHANICS$OF$MUSCLE$CONTRACTION!!
!
•! The!Light!(I)!Bands!W!Become!shorter!
•! The!Dark!(A)!Bands!W!Stay!the!same!length!
!
•! When!the!muscle!contracts,!the!sarcomeres!become!smaller!
o! However!the!filaments!do!not!change!in!length!
!! Instead!they!slide!past!each!other!(they!overlap)!W!The!Zone!of!‘Overlap’!is!
larger!
!
•! Energy!for!the!movement!comes!from!splitting!ATP!
o! The!energy!from!ATP!causes!the!angle!of!the!myosin!head!to!change,!which!allows!
the!myosin!heads!to!attach!to!actin!
!
•! Movement!of!the!myosin!heads!(attaching!and!detaching)!from!actin!causes!the!filaments!to!
slide!from!one!to!another!
o! This!movement!reduces!the!sarcomere!length!
!
THE$SEQUENCE$OF$EVENTS!!
1)! An!action!arrives!at!the!end!of!a!motor!neuron:!at!the!neuromuscular!junction!2)! Causing!the!release!of!the!neurotransmitter!acetylcholine!3)! This!initiates!an!action!in!the!muscle!cell!membrane!(Sarcolemma)!4)! This!action!is!carried!to!cell!membrane!called!TWtubules!5)! The!action!causes!the!sarcoplasmic!reticulum!to!release!its!store!of!calcium!into!the!
myofibrils!
6)! Ca2+!causes!tropomyosin!to!be!displaced!uncovering!myosin!binding!sites!on!action!7)! Myosin!cross!bridges!can!now!attach!and!the!cross!bridge!cycle!can!take!place!
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TOPIC&4&–&MOVEMENT&ANALYSIS& 7!!
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THE$SLIDING$FILAMENT$THEORY$!!
1)! Muscle$Activation$a)! The!motor!nerve!stimulates!an!action!potential!(impulse)!to!pass!down!a!neuron!
to!the!neuromuscular!junction!
b)! This!stimulates!the!sarcoplasmic!reticulum!to!release!calcium!into!the!muscle!cell!
!
2)! Muscle$Contraction$a)! Calcium!floods!into!the!muscle!cell!binding!with!troponin!allowing!actin!and!
myosin!to!bind!
b)! The!actin!and!myosin!cross!bridges!bind!and!contract!using!ATP!as!energy!!!
3)! Recharging$a)! ATP!is!reWsynthesised!allowing!actin!and!myosin!to!maintain!their!strong!
binding!state!
!
4)! Relaxation$a)! Relaxation!occurs!when!stimulation!of!the!nerve!stops!b)! Calcium!is!then!pumped!back!into!the!sarcoplasmic!reticulum!breaking!the!link!
between!actin!and!myosin!
c)! Action!and!myosin!return!to!their!unbound!state!causing!the!muscle!to!relax!d)! Alternatively!relaxation!will!also!occur!when!ATP!is!no!longer!available!
!
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THE$SLIDING$FILAMENT$THEORY$4$CONTRACTION$TO$OCCUR!!
•! There!must!be!a!neural!stimulus!
•! There!must!be!calcium!in!the!muscle!cells!
•! ATP!must!be!available!for!energy!
!
THE$SLIDING$FILAMENT$THEORY$4$CONTRACTION$TO$STOP!!
•! Energy!system!fatigue!
•! Nervous!system!fatigue!
•! Voluntary!nervous!system!control!
•! Sensory!nervous!system!information!
!
THE$CROSS$BRIDGE$CYCLE$$PROCESS! EXPLANATION! DIAGRAM!
Step!1!
!
●! ATP!binds!to!the!myosin!head!
!
●! This!causes!the!myosin!head!to!be!released!from!
actin!
!
!Step!2! ●! ATP!molecule!is!
hydrolysed!while!the!
myosin!head!is!
unattached!
!
ADP!+!Pi!formed!remain!bound!to!
the!myosin!head!
!
TOPIC&4&–&MOVEMENT&ANALYSIS& 9!!
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Step!3! ●! Energy!released!is!absorbed!by!the!myosin:!
!
○! Causing!the!
myosin!head!to!
change!shape!W!
Energings!state!/!
cocked!state!
!
It!then!binds!to!the!actin!filament!
!Step!4!W!5! ●! ADP!+!Pi!are!released!
from!the!myosin!head:!
!
○! Result!=!Power!
Stroke!Occurs!W!
Myosin!head!
changes!shape!
!
This!draws!the!actin!filament!
over!the!myosin!filament! !
Beginning!
Again!
●! The!cycle!begins!again!when!the!next!ATP!binds!
to!the!myosin!head:!
!
Causing!the!myosin!head!to!be!
released!from!actin!
!!
MUSCLE$CONTRACTIONS!!
MUSCLE$TYPE! DESCRIPTION! DIAGRAM!Stretched!Muscle! ●! The!I!Bands!and!the!H!
Zone!is!elongated!due!
to!reduced!
overlapping!of!the!
myosin!and!actin!
filaments!
!
There!would!be!reduced! !
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!
muscle!strength!because!few!
cross!bridges!can!form!
between!the!actin!and!myosin!!
Partially!Contracted!Muscle! ●! There!is!more!overlapping!of!the!
myosin!and!actin!with!
lots!of!potential!for!
cross!bridges!to!form!
!
The!I!Bands!and!H!Zone!are!
shortened! !Full!Contracted!Muscle! ●! Lots!of!overlap!
between!the!actin!and!
myosin!
!
●! Thin!actin!filaments!have!overlapped!there!
is!a!reduced!potential!
for!cross!bridges!to!
form!again!
!
Therefore!there!will!be!low!
force!production!from!the!
muscle!
!
!
DURING$MUSCLE$CONTRACTIONS!!
•! The!myosin!heads!on!the!thick!filaments!‘hook’!onto,!and!so!pull,!the!thin!filaments!
towards!the!centre:!the!M!W!Line!of!each!sarcomere!
•! The!appearance!of!this!action!is!shown!above!as!the!transition!from!‘relaxed’!to!‘fully!
contracted’!muscle!
•! As!the!thin!filaments!slide!over!the!thick!filaments!W!the!I!Bands!and!H!Zones!become!
narrower!and!narrower!until!they!disappear!when!the!muscle!reaches!its!fully!
contracted!state!
!
DURING$MUSCLE$RELAXATION!!
•! When!the!myosin!heads!on!the!thick!filaments!relax!they!release!their!hold!on!the!
thin!filaments,!thereby!allowing!them!to!slide!back!to!their!‘relaxed’!positions!in!
which!the!I!Bands!and!H!Zones!appear!again!
!
WHOLE$PROCESS!
TOPIC&4&–&MOVEMENT&ANALYSIS& 11!!
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12& TOPIC&4&–&MOVEMENT&ANALYSIS!!
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4.1.4$4$Explain$how$slow$and$fast$twitch$fibres$types$differ$in$structure$and$function!!
•! Skeletal!muscles!contain!2!main!types!of!fibres,!which!differ!in!the!primary!
mechanisms!they!use!to!produce!ATP,!the!type!of!motor!neuron!innervation,!and!the!
type!of!myosin!heavy!chain!expressed!
!
•! The!proportions!of!each!type!of!fibre!varies!from!muscle!to!muscle,!from!animal!to!
animal,!and!from!person!to!person!
!
TYPES$OF$MOTOR$UNITS!!
TYPE$I!•! Slow!twitch!fibre!
!
o! Red!in!colour!due!to!the!presence!of!large!volumes!of!myoglobin!=!oxygen!and!
high!numbers!of!mitochondria!
o! Resistant!to!fatigue!and!capable!of!producing!repeated!lowWlevel!contractions!by!
producing!large!amount!of!ATP!through!an!aerobic!metabolic!cycle!
!
o! Fibres!contract!slowly!but!can!contract!repeatedly!over!long!periods!
!
!! Sporting!Example:!
•! Walking!
•! Cycling!
o! For!30!minutes,!at!low!intensity!
!
TYPE$IIa!•! Fast!twitch!fibre!
!
o! Fast!oxidative!fibres!!
o! Contain!a!large!number!of!mitochondria!and!myoglobin!=!red!in!colour!
!
o! They!manufacture!and!split!ATP!at!a!fast!rate!by!utilising!both!aerobic!and!
anaerobic!metabolism!!
o! Produce!fast,!strong!muscle!contraction,!although!they!are!more!prone!to!fatigue!
!
o! Fast!contraction!speed!
o! ‘White!Fibres’!as!they!are!less!reliant!on!oxygen!supplied!by!the!blood!for!energy!!
!
!! Sporting!Example:!
•! Suited!to!speed,!strength!and!power!type!activities!
o! Heavy!weight!training!(8!W!12!reps)!
o! Fast!running:!400m!
!
TYPE$IIb!•! Fast!twitch!fibre!
!
o! Fast!glycolytic!fibres!they!are!white!in!colour!due!to!a!low!level!of!myoglobin!and!
also!contain!few!mitochondria!
o! They!produce!ATP!at!a!slow!rate!by!anaerobic!metabolism!and!break!it!down!
very!quickly!=!short,!fast!bursts!of!power!and!rapid!fatigue!
!
TOPIC&4&–&MOVEMENT&ANALYSIS& 13!!
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!! Sporting!Example:!
•! Suited!to!speed,!strength!and!power!type!activities!
o! Heavy!weight!training!(1!W!3!reps)!
o! Fast!running:!100m!
!
! TYPE$OF$MOTOR$UNIT!SITUATION! TYPE$I! TYPE$IA! TYPE$IB!
Contraction!Time! Slow! Moderately!Fast! Very!Fast!
Size!of!Motor!Neuron! Small!! Medium! Large!
Resistance!to!Fatigue! High! Intermediate! Low!
Activity!Used!For! Aerobic! Long!W!Term!
Anaerobic!
Short!W!Term!
Anaerobic!
Maximum!Duration!of!
Use!
Hours! <!30!Minutes! <!1!Minutes!
Power!Produced! Low! Medium! High!
Mitochondrial!
Density!
High! Medium!! Low!
Capillary!Density! High! Intermediate! Low!
Oxidative!Capacity! Hight! Medium! Low!
Glycolytic!Capacity! Low! High! High!
Major!Storage!Fuel! Triglycerides! Creatine!Phosphate!
Glycogen!
ATP!
Creatine!Phosphate!
Note! Consume!Lactic!Acid! Produce!Lactic!Acid!
Produce!Creatine!
Phosphate!
Consume!Creatine!
Phosphate!
!
! TWITCH$FIBRE!SITUATION! FAST$4$TWITCH$
FIBRES!SITUATION! FAST$4$TWITCH$
FIBRES!Type!of!Work!
Performed!
Strength! Type!of!Work!
Performed!
Strength!
Suited!Activities! Rapid!movements!
(speed)!
Suited!Activities! Rapid!movements!
(speed)!
Type!of!Athlete! Sprinters! Type!of!Athlete! Sprinters!
Type!of!Respiration! Anaerobic! Type!of!Respiration! Anaerobic!
Blood!Supply! Fewer!blood!vessels! Blood!Supply! Fewer!blood!vessels!
Energy!Release! Small!amount!quickly! Energy!Release! Small!amount!quickly!
Number!of!
Mitochondria!
Less!mitochondria! Number!of!
Mitochondria!
Less!mitochondria!
Amount!of!Myoglobin! Less!myoglobin! Amount!of!Myoglobin! Less!myoglobin!
! TWITCH$FIBRE! ! TWITCH$FIBRE!SITUATION! FAST$4$TWITCH$
FIBRES!SITUATION! FAST$4$TWITCH$
FIBRES!Type!of!Work!
Performed!
Strength! Type!of!Work!
Performed!
Strength!
Suited!Activities! Rapid!movements!
(speed)!
Suited!Activities! Rapid!movements!
(speed)!
!
FAST$4$TWITCH$FIBRES! SLOW$4$TWITCH$FIBRES!Efficient!in!using!oxygen! Do!not!burn!oxygen!to!create!energy!
Delayed!muscle!firing! Fast!to!fire;!best!for!explosive!body!movement!
Do!not!fatigue!easily! Tire!out!quickly!
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!
Best!suited!for:!
•! Endurance!sports!
o! Cycling!
o! Marathon!running!
•! LongWdistance!triathlon!
Best!suited!for:!
•! Short!bursts!of!activity!
o! Sprinting!races!
o! Pole!vaulting!
•! Cross!fitWstyle!events!
Responds!rapidly!to!nervous!stimulation! Contract!more!slowly!
Contain!myosin!that!can!break!down!ATP! Small!in!diameter!
Fewer!and!smaller!mitochondria! Better!blood!supply!
Comes!in!oxidative!and!glycolytic! More!mitochondria!
Intense!movements! More!fatigueWresistant!than!fastWtwitch!
Short!durations! Large!amount!of!myoglobin!
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