Kin 1A03 McMaster Final Exam Review UPDATED ACTUAL Exam Questions and CORRECT Answers
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Kin 1A03 McMaster
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Kin 1A03 McMaster
Kin 1A03 McMaster Final Exam Review
UPDATED ACTUAL Exam Questions and
CORRECT Answers
excitation-contraction coupling - CORRECT ANSWER- AP from NS turns into muscle
contraction
-MAP propagated along sarcolemma into t-tubules
-Ca+ channels in SR open and release into sarcoplasm
-Ca+ bind...
Kin 1A03 McMaster Final Exam Review
UPDATED ACTUAL Exam Questions and
CORRECT Answers
excitation-contraction coupling - CORRECT ANSWER- ✔✔AP from NS turns into muscle
contraction
-MAP propagated along sarcolemma into t-tubules
-Ca+ channels in SR open and release into sarcoplasm
-Ca+ binds to troponin and tropomyosin detaches
-X bridge forms
myofibril - CORRECT ANSWER- ✔✔entire muscles length - series of sarcomeres
state of each of the bands when muscle is relaxed vs contracted - CORRECT ANSWER-
✔✔A band (all of myosin)
H zone - only myosin
I band - only actin
A band doesn't change, I Band and H zone disappear
fully contracted - length of sarcomere = - CORRECT ANSWER- ✔✔length of A band
myosin 'activated state' - CORRECT ANSWER- ✔✔ADP and iP are bound and ATP is stored
how does myosin get ADP and Pi - CORRECT ANSWER- ✔✔ATPase on myosin heads
HYDROLYZE ATP
which is released 1st - phosphate or ADP? - CORRECT ANSWER- ✔✔phosphate - releases
once once cross bridge is formed
ADP released during power stroke
,Rigor Mortis - CORRECT ANSWER- ✔✔death - Ca channels leak and muscles are stuck in
contraction = stiffness
need ATP to stop a muscle contraction
does skeletal muscle or NS have more leak channels? - CORRECT ANSWER- ✔✔SM
therefore higher mem pot
K - CORRECT ANSWER- ✔✔KIN
What needs ATP in muscle contraction - CORRECT ANSWER- ✔✔-Myosin
-NaK pumps
-circa pumps
depolarization of muscle cell - CORRECT ANSWER- ✔✔signal -> musc
Na+ rushes into cell and stimulates AP
how many nerve connections on each muscle fiber? - CORRECT ANSWER- ✔✔1
NMJ
myofibril - CORRECT ANSWER- ✔✔contractile portion of muscle
where does the axon branch out (MAP) - CORRECT ANSWER- ✔✔perimysium, then serves
many diff muscle fibres
axon collateral = 1 branch
reaches sarcolemma and branches a little more to form synaptic end bulb
what lvl is ACh released into and what causes the release - CORRECT ANSWER-
✔✔sarcolemma
,as long as enough ACh is released, reach threshold in sarcolemma, cause excitatory post-
synaptic potential (depolarization) and cause MAP
Nerve impulse reaches synaptic end bulb and triggers opening of Ca release channels. Ca
triggers mvt of vesicles towards cleft where ACh is released via exocytosis
what types of channels are in the motor end plate of the sarcolemma - CORRECT ANSWER-
✔✔ligand - retrieve ACh
voltage
what breaks down ACh in synaptic cleft? - CORRECT ANSWER- ✔✔AChesterase
-choline goes back in and rebinds
-acetic acid gets absorbed by neighbouring cells
whats the difference btwn an NMJ vs an NNJ - CORRECT ANSWER- ✔✔-always have ACh
release > depolarization
-voltage close to ligand
-AP in middle and spreads outwards
MAP starts where - CORRECT ANSWER- ✔✔sarcolemma
drops down into t tub once finds one
mem pot change in tt causes SR release channels to open
Ca > sarcoplasm and DIFFUSES into X bridge area
how do you stop muscle contraction - CORRECT ANSWER- ✔✔-ATP stops binding
-Ca taken back up into SR (circa pumps) - need ATP to activate pump and suck Ca back in
-ACHestase wins
motor unit - CORRECT ANSWER- ✔✔1 somatic motor neuron and several different fibres
-each fiber gets 1 NMJ
-only branch to fibres of a specific type - slow or fast twitch
, -different muscle type = diff # of branches - dexterity vs gross control
when is maximal muscle tension produced? - CORRECT ANSWER- ✔✔motor unit
summation
when you train, you build more ____ - CORRECT ANSWER- ✔✔myofibrils in each fiber
isometric contraction - CORRECT ANSWER- ✔✔length of muscle is constant but tension
changes
i.e. trying to lift desk cemented to ground
isotonic contraction - CORRECT ANSWER- ✔✔constant tension produced, muscle length
changes
-concentric: muscle shortens - musc force > external force (tension overcomes resistance)
-eccentric: muscle shortens - muscle force < external force (resistance overcomes tension -
myosin-actin tug of war)
muscle twitch - CORRECT ANSWER- ✔✔force produced, send AP thru nerve, cross bridges
are working
type 1 muscle fiber - CORRECT ANSWER- ✔✔slow (high) oxidative (metabolism used for
energy)
-slower cross bridge cycling, slow ATP breakdown, slower myosinATPase
-smaller in diameter - less myofibrils
-more mitochondria > more ATP > better blood supply
-fatigue resistent
Type 2A muscle fibers - CORRECT ANSWER- ✔✔Fast Oxidative-Glycolytic - fast twitch,
low oxidative, intermediate fiber
-fast ATP breakdown, larger and stronger than type 1
-relies mainly on glycolysis so has less mitochondria and less blood supply
-still relies a little bit on oxidative
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