5.1 Skeletal muscle Flashcards

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1
Q

what is each muscle composed of?

A

muscle fibres

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2
Q

what is the connective tissue called that bundles fibres together?

A

SARCOLEMMA

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3
Q

what are the smaller fibres in muscles called?

A

myofibrils

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4
Q

what do myofibrils contain?

A

2 types of protein

myosin and actin

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5
Q

muscles are made of…

A

fasicles

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6
Q

fascicles are made of…

A

muscle fibres

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7
Q

muscle fibres are made of…

A

myofibrils

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8
Q

myofibrils are broken down into…

A

sarcomeres

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9
Q

sarcomeres are made of…

A

thin & thick filaments (actin and myosin)

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10
Q

what are the I bands and why?

A

light - actin and myosin don’t overlap

only actin there

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11
Q

what is the A band and why?

A

dark bands
appear darkest where actin and myosin overlap
darkness due to presence of thick myosin filaments

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12
Q

where is the Z line found?

A

at the centre of each light band

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13
Q

what is the distance between the two z lines?

A

the sarcomere

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14
Q

what happens to the sarcomere when muscle contracts?

A

it shortens, z bands move closer and I bands nearly disappear

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15
Q

what is the H zone?

A

a lighter coloured region in the centre of the dark band

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16
Q

what is in the H zone?

A

only myosin filaments

17
Q

what are the two different types of muscle fibres in skeletal muscle?

A

slow twitch and fast twitch

18
Q

do slow twitch fibres contract slowly or quickly?

A

slowly

19
Q

are slow twitch fibres more or less powerful over time?

A

less powerful

20
Q

what are slow twitch fibres used for?

A

endurance activities

21
Q

do slow twitch fibres tire easily?

A

no

22
Q

where is slow twitch fibres energy gained from?

A

aerobic respiration

23
Q

what are slow twitch fibres rich in?

A

myoglobin, blood vessels and mitochondria

24
Q

Where are slow twitch fibres found in large proportion?

A

Muscles that maintain posture e.g. Back and calf muscles

25
Q

Do fast twitch fibres contract quick or slow?

A

Quickly

26
Q

Do fast twitch fibres give powerful contractions?

A

Yes for short periods

27
Q

What are fast twitch fibres used for?

A

Short birds of speed and power

28
Q

Do fast twitch fibres tire easily?

A

Yes

29
Q

Where do fast twitch fibres gain energy from?

A

Anaerobic respiration

30
Q

What colour are fast twitch fibres?

A

Pale

31
Q

What are fast twitch fibres low in?

A

Levels of myoglobin and blood vessels

32
Q

What do fast twitch fibres have more of?

A

More thick myosin filaments

33
Q

What do fast twitch fibres store?

A

Creatine phosphate

34
Q

What does creatine phosphate do?

A

Rapidly generates ATP from ADP in anaerobic conditions

35
Q

Where are fast twitch fibres found in high proportions?

A

In muscles that need short bursts of energy such as biceps and eyes

36
Q

What are myofibrils?

A

Long cylindrical organelles
Made of actin and myosin
Specialised for contraction
Lined up parallel to provide maximum force

37
Q

What is actin?

A

Filament consisting of two strands twisted around each other

38
Q

What is myosin?

A

The thick filament consisting of rod shaped fibres with bulbous heads that project to one side

39
Q

How many actin to one myosin?

A

Six