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602 EX 2 > muscle physiology 1 > Flashcards

muscle physiology 1 Flashcards

1
Q

________ is the the sliding of actin past myosin generates muscle tension

A

Sliding filament theory

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2
Q

_______ is the smallest contractile unit of a muscle fiber

A

Sarcomere

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3
Q

compare the bands and lines in a sarcomere (I, A, M, Z)

A

-I band: light portion made up of actin filaments (thin filament)
-A band: dark portion made up of myosin (thick filament)
-M line: in very middle
-Z line: where two neighboring I bands meet

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4
Q

during a contraction how do the Z lines change?

A

the distance between the two Z-lines decreases because the Z-line moves toward the H-line

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5
Q

does the length of the A band change during a contraction?

A

no

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6
Q

does the length of the I band change during a contraction?

A

yes

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7
Q

Crossbridge linkage between thick and thin filaments are achieved by what two things?

A

-Chemical and/or electrostatic linkages
-Force generation/ number of bonds between myosin and actin that are made in parallel

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8
Q

______ cross bridges = more force

A

more

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9
Q

what does in parallel vs in series mean?

A

-In Parallel: more than one sarcomere is contracting at the same time in different myofibrils. We assume that other myofibers are extending too
-In series: consecutive sarcomeres of one myofibril are contracting. We assume that one myofiber is contracting while others are not

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10
Q

In parallel has ____ chance of producing muscle shortening, while series has _____ chance

A

GREATER, LESS

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11
Q

Force generation is _____kg/cm2 cross-sectional area of muscle

A

3-4kg per cm2

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12
Q

Skeletal muscle in males is _____% body weight, while in females muscle is only ____% body weight

A

40, 32

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13
Q

Edible mussels generate _____ force in shell retractor

A

15kg/cm2

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14
Q

do males and females generate the same force per cm2?

A

yes

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15
Q

what is the lever ratio?

A

power arm of lever : load arm of lever

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16
Q

What does it mean if there is a 1:7 lever ratio?

A

This means, for every 1cm the muscle (bicep) moves, the hand (or limb attached) will move 7 cm

17
Q

what is the tension to lift weight formula

A

Tension to lift weight = (weight)(1/ratio)

18
Q

Short distance of bicep contraction = ______ mvmt of hand with great speed

A

large

19
Q

Forceful exercise produces _______ that results in hypertrophy of myofibers. what does this mean?

A

hyperplasia of myofibrils
-myofibrils split forming more myofibrils within a myofiber

20
Q

does hyperplasia of myofibrils create more myofibrils in series or parallel?

A

parallel

21
Q

do long-distane runners experience hypertrophy?

A

no, because they are not exercising their muscles at maximal load

22
Q

sprinters experience ________ which adds myofibrils in parallel

A

myofiber hypertrophy

23
Q

why are bodybuilders so big?

A

-Muscles are larger due to more blood and interstitial fluid in the muscle and more water/sarcoplasmic fluid in each myofiber (sarcoplasmic hypertrophy)
NOT due to myofibril hyperplasia

24
Q

Negative mutation of _________ gene can increase muscle mass naturally

A

myostatin (Gdf8)

25
Q

________ is the amount of tension that is produced by a muscle as a feature of its length

A

Length tension

26
Q

when is max force of a muscle?

A

when greatest number of crossbridge bonds are made at parallel

27
Q

Range of muscle length is greatest within____ of 100% resting muscle length

A

+/-30%

28
Q

why is muscle not in a constant state of contraction?

A

because regulator proteins actively inhibit contraction

29
Q

________ sits on top of myosin binding sites on the actin helix.______ sits on top of tropomyosin

A

Tropomyosin, Troponin

30
Q

explain the relaxation/excitement cycle

A

-No Ca+ = no crossbridge binding, myosin binding site is covered by troponin/tropomyosin complex
-ATP bound to myosin head
-Ca+ enters
-Ca+ binds to troponin
-Troponin rotates on itself and pulls tropomyosin out of the way
-Cross-bridge sites are now exposed
-Binding of Myosin cross bridge to –Actin triggers the power stroke that pulls the thin filament inward during contraction
-During power stroke, ATP hydrolyzed → ADP

31
Q

Myosin’s ATPase is active when ________

A

myosin is attached to actin

32
Q

There are __ heads on each myosin, and __ binding sites on each head

A

2,2

33
Q

what are the 2 binding sites on myosin heads?

A

-Myosin ATPase (where ATP → ADP + Pi)
-Actin binding site

34
Q

Change of angle from one row to another = wedged ____ (every 3)

A

40* CCW

602 EX 2 (13 decks)

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