5.1 Skeletal muscle Flashcards Preview

A Level Biology > 5.1 Skeletal muscle > Flashcards

Flashcards in 5.1 Skeletal muscle Deck (39):
1

what is each muscle composed of?

muscle fibres

2

what is the connective tissue called that bundles fibres together?

SARCOLEMMA

3

what are the smaller fibres in muscles called?

myofibrils

4

what do myofibrils contain?

2 types of protein
myosin and actin

5

muscles are made of...

fasicles

6

fascicles are made of...

muscle fibres

7

muscle fibres are made of...

myofibrils

8

myofibrils are broken down into...

sarcomeres

9

sarcomeres are made of...

thin & thick filaments (actin and myosin)

10

what are the I bands and why?

light - actin and myosin don't overlap
only actin there

11

what is the A band and why?

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

12

where is the Z line found?

at the centre of each light band

13

what is the distance between the two z lines?

the sarcomere

14

what happens to the sarcomere when muscle contracts?

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

15

what is the H zone?

a lighter coloured region in the centre of the dark band

16

what is in the H zone?

only myosin filaments

17

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

slow twitch and fast twitch

18

do slow twitch fibres contract slowly or quickly?

slowly

19

are slow twitch fibres more or less powerful over time?

less powerful

20

what are slow twitch fibres used for?

endurance activities

21

do slow twitch fibres tire easily?

no

22

where is slow twitch fibres energy gained from?

aerobic respiration

23

what are slow twitch fibres rich in?

myoglobin, blood vessels and mitochondria

24

Where are slow twitch fibres found in large proportion?

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

25

Do fast twitch fibres contract quick or slow?

Quickly

26

Do fast twitch fibres give powerful contractions?

Yes for short periods

27

What are fast twitch fibres used for?

Short birds of speed and power

28

Do fast twitch fibres tire easily?

Yes

29

Where do fast twitch fibres gain energy from?

Anaerobic respiration

30

What colour are fast twitch fibres?

Pale

31

What are fast twitch fibres low in?

Levels of myoglobin and blood vessels

32

What do fast twitch fibres have more of?

More thick myosin filaments

33

What do fast twitch fibres store?

Creatine phosphate

34

What does creatine phosphate do?

Rapidly generates ATP from ADP in anaerobic conditions

35

Where are fast twitch fibres found in high proportions?

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

36

What are myofibrils?

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

37

What is actin?

Filament consisting of two strands twisted around each other

38

What is myosin?

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

39

How many actin to one myosin?

Six

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