midterm review Flashcards by K M

proteins found in a sarcomere

actin
myosin
ATPase
troponin
tropomyosin

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proteins involved in muscle contraction

actin
myosin
ATPase
troponin
tropomyosin

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proteins that can prevent muscle contraction

troponin
tropomyosin

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fastest contracting fiber type

type Iix fiber

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energy currency of a cell

ATP

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enzyme involved in a muscle contraction

ATPase

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which of the following is the smallest structure
a) muscle fiber
b) myosin
c) myofibril
d) sarcomere

myosin

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an enzyme:
a) is a protein
b) is a molecule that increases the rate of chemical reactions
c) could change its level following
d) all of the above

d) all of the above

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what suffix is commonly use to describe an enzyme

ase

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using this suffix name the enzyme that is involved in the reaction where ATP is broken down for energy

ATPase

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which protein interacts with myosin during muscle contraction

actin

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which 2 proteins are involved in the blocking of myosin to prevent muscle contraction

troponin
tropomyosin

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see diagrams

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true or false
there are three main fiber types: fast (Iix), intermediate (IIa) and slow (I)

true

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true or false
the fiber types an individual posses is determined by genetics and cannot be changed

false

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true or false
Type I fibers are the fastest contracting fibers in humans

false

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true or false
strength training leads to a conversion of slow fibers to fast fibers

false

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types of myosin heavy chains
list from fastest to slowest contracting
type I
type Iix
type IIa

Type IIx
type IIa
type I

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put in order from largest to smallest
-sarcomeres
-myofibrils
-whole muscle
-muscel fasicle
- actin and myosin
-muscle fibers
-myoisn heavy chains

Whole muscle
muscle fascicles
Muscle fibers
myofibirls
actin, myosin
myosin heavy chains

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what are considered contractile proteins

actin and myosin

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what are considered regulatory proteins

troponin and tropomyosin

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which protien binds calcium

troponin

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what is bordered by z discs

sarcomere

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what protein blocks binding sites on actin

tropomyosin

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what protein controls speed of contraction

ATPase

after muscle contracts, what ion must be removed from the cytoplasm of your muscle cells before muscle relaxation can occur

calcium

put in following steps in the process of contraction in proper order -myosin binds to actin -muscle relaxes -calcium binds to troponin -ATP broken down -dissociation of actin and myosin -calcium is removed from troponin -troponin lifts off tropomyosin off actin

calcium binds to troponin troponin lifts tropomyosin off actin myosin binds to actin ATP broken down dissociation of actin and myosin

with which type of muscle contraction can you generate the most force

eccentric

which of the following shortens during a muscle contraction sarcomere, myosin, actin

sarcomere

where is the enzyme ATPase found in skeletal muscle

myosin head sarcoplasmic reticulum mitochondria

how does ability to generate muscular force changes as velocity of concentration increases?

As velocity increases the ability to generate muscle force decreases, actin and myosin don’t from cross bridges as efficiently at faster speeds.

which fiber type has high ATPase fast-fatiguability

Type IIX

which fibre type has low ATPase slow twitch

Type I

which fiber type has fast fatigue resistant

type IIA

see diagram

what is force summation and what causes it

Before a muscle relaxes from a contraction, if another electrical signal is applied once increased to a higher level What causes it * this is due to increased release of calcium from the SR * the calcium will bind more troponin, lifting tropomyosin allowing more myosin actin cross bridges

what is tetanus and what causes it

Force will only summate up to a maximal level with receptive stimulation This maximal level is reaches one all their for calcium on troponin have been occupied therefore no more cars bridges can occur

classification baed on myosin heavy chain chains (ATPase activity)

type I type IIA type IIX

classification based on metabolic properties

slow oxidative fast glycolytic

describe how motor unit recruitment (recruitment of fast or slow twitch or intermediate motor units) would change as one goes from a duo walk to a jog to a sprint

Recruitment type 1 slow twitch during walk, as intensity increases recruit more and more fast twitch

which receptor, when activated causes reflex contraction of muscle ?

muscle spindle

which receptor when activated causes inhibition of contraction?

Golgi tendon organ

which receptor do you think causes inhibition if antagonistic musculastrucnture

muscle spindle

which receptor do you think causes activation of antagonistic musculastructure (if the receptor in the quadriceps is activated, it would cause activation of the hamstrings)

Golgi tendon organ

reflex contraction of a muscle after spindle activation

efferent

voluntary contraction of your biceps by recruitment of motor neurons in the spinal cord

efferent

your eyes transmit a signal to your brain about the position of a soccer ball

afferent

vestibular (inner ear) sensors send a message to your brain to correct your balance

afferent

a motor neuron recieven 10 excitatory impulses form one other neruon over the time period of 2 milliseconds

temporal summation

another motor neuron receives one excitatory impulse from each of 5 different neurons

spatial summation

true or false a motor unit has only one motor neuron but many muscle fibers

true

true or false a motor unit can have a mixture of slow twitch and fast twitch muscle fibers

false

true or false when a motor neruon, is activated only a portion of the muscle fibers in that motor unit will contract if low intensity exercise is being performed

false all or none

true or false motor units in different muscles throughout the body are the same size

false Some are big for grow movement others are small for fine movement

motor neuron, motor pool and motor unit

where calcium is stored

sarcoplasmic reticulum

influx/efflux of these cause change in membrane potential

sodium and potassium

transmit AP from neuron to muscle fiber

transerve tubule

nerve cells connected to muscles fibers

motor neurons

part of the brain where voluntary contraction originates

motor cortex

excites membrane and changes permeability

acetylcholine

covered by a myelin sheaf

axons

a motor neuron and all the muscle fibers that are connected to it

motor unit

fast twitch muscle fibers require a higher frequency electrical input to reach tetanus compared to slow bewitch fibers. why is this so?

Because they relax faster

membrane potential changes from -70 to -90 mV

hyper polarize

membrane potential changes from -70 to -50 -80 to -70

depolarize

membrane potential changes from +40 to -60mV

re-polarize

if someone trains just one limb for a period of time, but also sees an increase in strength in the opposite (untrained limb) this natural phenomena is called?

cross-education mechanisms: (recruiting ipsilateral pathways, ceiling effect,

the neural phenomenon of the sum strength of two unilateral limbs being greater than when both limbs are used simultaneously is called

bilateral deficit mechanisms (trunk stability, more stable with more joints train bilaterally you can improve bilateral movement and decrease bilateral deficit inter hemisphere inhibition )

largest to smallest muscle fascicle muscle cell (muscle fiber) myofibril myofilaments

write out the steps of excitation contraction coupling, up to and including relaxation of the muscle

1. Impulse is received, calcium causes sac like Vesicles in the axon terminal release ACh. Ach diffuses across synaptic Cleft, attach to receptors in sarcolemma, changes membrane permeability 2. If at threshold, AP depolarizes T-tubule 3. Depolarization of T-tubule causes Ca2+ to be released from SR 4. Ca2+ binds to troponin and tropo- myosin, allowing myosin & actin to combine 5. Actin combines with myosin, ATPase is Activated to split ATP = energy 6. Sliding of actin and myosin, cross-bridge detaches from actin 7. Continued new cross-bridge action occurs if Ca2+remains high (membrane depolarization inhibits action of troponin- tropomyosin complex) 8. Muscle stimulation stops, Ca2+ moves back into SR 9. Removal of Ca2+ reinstates troponin- tropomyosin inhibitory action, actin and myosin stay in relaxed state (disassociated)