Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

biology > Muscles > Flashcards

Muscles Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

what do muscles act as?

A

antagonistic pairs against an incompressible skeleton to create movement. either automatic or conscious

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

antagonistic meaning

A

2 muscles attached, working in opposites to either contract or relax

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what are muscle fibres made up of and what are these made up of?

A

myofibrils, which are made up of fused cells sharing nuclei and a sarcoplasm with many mitochondria, due to lots of ATP being essential for contraction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what are the 2 proteins that myofibrils are made up of?

A

myosin and actin (they form a sarcomere)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

is actin a thin or thick filament?

A

thin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

is myosin a thin or thick filament?

A

thick

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

explain the process of the sliding filament theory (6)

A

-when an action potential reaches a muscle, a response is then stimulated.
-Ca2+ ions enter and cause tropomyosin (protein) to uncover binding sites for myosin, exposing them.
-ADP is attached to the myosin head and can bind to the binding sites on the actin to form a cross-bridge.
-the angle created here creates tension, so the actin filament is pulled and slides along the myosin, releasing an ADP molecule.
-an ATP molecule can then bind to the myosin head, causing a shape change, so it detaches.
-in the sarcoplasm, ATPase hydrolyses ATP to ADP on the myosin, releasing energy to return to normal position.
-the process repeats whilst Ca2+ conc remains high and muscle remains stimulated.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

how is the enzyme ATPase activated?

A

by Ca2+ ions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what happens when not enough ATP is produced in aerobic respiration?

A

anaerobic respiration will occur and the chemical phosphocreatine assists by providing phosphate to regenerate ATP from ADP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

where is phosphocreatine stored?

A

in the muscles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what does the A band show on a myofibril?

A

all of the myosin filament, whether or not it is overlapping

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what does the I band show on a myofibril?

A

actin only (thin letter)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what does the H zone show on a myofibril?

A

myosin only (thick letter)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what does the M line show on a myofibril?

A

middle of the myosin filaments

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what does the Z line show on a myofibril?

A

the end of the sarcomere (end of alphabet)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

which bands/zones decrease during contraction and why?

A

I band and H zone, due to actin on both sides of sarcomere being closer together

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

which band/zone increases during contraction?

A

Z line

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

which band/zone doesn’t change during contraction?

A

A band

19
Q

describe the structure of a slow-twitch muscle fibre

A

there’s a large store of myoglobin, a rich blood supply, and lots of mitochondria

20
Q

describe the structure of a fast-twitch muscle fibre

A

they are thicker with more myosin filaments, a large store of glycogen and phosphocreatine (to make ATP), and a high conc of enzymes from anaerobic respiration

21
Q

where are slow-twitch muscle fibres located?

A

the calf muscles

22
Q

where are fast-twitch muscle fibres located?

A

the bicep muscles

23
Q

describe the properties of slow-twitch muscle fibres

A

they contract slower and can respire aerobically for longer due to the rich blood supply and myoglobin store

24
Q

describe the properties of fast-twitch muscle fibres

A

they contract faster to provide short bursts of contraction

25
Q

what are slow-twitch muscle fibres adapted for?

A

endurance (e.g. marathons)

26
Q

what are fast-twitch muscle fibres adapted for?

A

intensity (e.g. sprints and weightlifting)

27
Q

which muscle fibre takes longer to fatigue?

A

slow-twitch muscle fibres

28
Q

how does a neuromuscular junction work?

A

1) Impulses arriving at the neuromuscular junction cause vesicles to fuse with the pre-synaptic membrane and release acetylcholine into the gap.
2) acetylcholine binds to receptors on the sarcolemma (muscle fibre membrane), causing depolarisation.
3) the depolarisation wave travels down the tubules (T system).
4) T system depolarisation leads to release of Ca2+ ions from the sarcoplasmic reticulum.
5) Ca2+ binds to proteins in the muscle, leading to contraction.
6) acetylcholinerase in the gap rapidly breaks down acetylcholine, so contraction only occur when impulses arrive continuously.

29
Q

what is the sarcolemma?

A

the muscle fibre membrane

30
Q

is an action potential created in the post-synaptic membrane of a normal synapse?

A

yes

31
Q

is an action potential created in the post-synaptic membrane of a neuromuscular junction?

A

no, it ends here

32
Q

are neurotransmitters excitatory or inhibitory in a normal synapse?

A

either

33
Q

are neurotransmitters excitatory or inhibitory in a neuromuscular junction?

A

excitatory

34
Q

is summation possible in a normal synapse?

A

yes

35
Q

is summation possible in a neuromuscular junction?

A

only temporal

36
Q

what are the connections between in a normal synapse?

A

neurone and neurone

37
Q

what are the connections between in a neuromuscular junction?

A

neurone and muscle fibre

38
Q

describe the structure of myosin

A

-each myosin filament is made up of 200 myosin molecules
-each myosin molecule has 2 protruding heads and a long tail
-each head contains ATPase, to hydrolyse ATP for muscle contraction

39
Q

describe the structure of actin

A

-each actin filament is made up of 2 actin molecules and a second protein called tropomyosin
-sites which can bind to myosin heads, but in a RELAXED muscle, tropomyosin blocks these
-Ca2+ ions cause tropomyosin to move to expose the binding sites on actin sop that contraction can occur

40
Q

what happens to the sarcomere during contraction?

A

it shortens

41
Q

what happens to the H zone during contraction?

A

it becomes narrower

42
Q

what happens to the I band during contraction?

A

it becomes narrower

43
Q

what happens to the Z lines during contraction?

A

they become closer together

44
Q

what happens to the A band during contraction?

A

it stays the same

biology (18 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions