Brainscape's Knowledge GenomeTM

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


See full index

Biology 5.1.5: Animal Responses > skeletal muscles > Flashcards

skeletal muscles Flashcards

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

describe the role of muscles

A
  • act in antagonistic pairs
  • against an incompressible skeleton
  • creating movement
  • part of reflex or controlled by conscious thought
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what is a myofibril?

A
  • fused cell
  • shares a nucleus & cytoplasm (sarcoplasm)
  • has many mitochondria
  • membrane bound channels (sarcoplasmic reticulum)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what are myofibrils made up of?

A

myosin and actin proteins forming a sarcomere

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

describe the myosin proteins

A

thick protein filament

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

describe the actin proteins

A

thin protein filament

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

describe the position of the sarcomere proteins

A

each myosin filament surrounded by six actin filaments

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

what is the sliding filament theory?

A

when an action potential reaches a muscle, it stimulates the response

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

first stage of sliding filament

A

Ca2+ ions enter and cause trypomyosin to move and uncover binding sites

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

describe the position of the trypomyosin

A
  • wrapped around actin protein
  • blocks binding sites for myosin head when muscle is relaxed
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

second stage of sliding filament

A
  • ADP is attached to myosin head
  • myosin head binds to binding site on actin, forming a cross bridge
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

third stage of sliding filament

A
  • angle created in cross bridge creates tension
  • actin filament is pulled and slides along the myosin
  • releasing ADP
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

fourth stage of sliding filament

A
  • ATP molecule binds to myosin
  • causes it to change shape and detach from actin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

fifth stage of sliding filament

A
  • Ca2+ ions activate enzyme ATPase in sarcoplasm
  • ATPase hydrolyses ATP on myosin head into ADP and releases enough energy for myosin head to return to original position
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what happens when aerobic respiration cannot create enough ATP to meet the demand?

A
  • anaerobic respiration
  • phosphocreatine which is stored in muscles, provides phosphate to regenerate ATP from ADP
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what does the I band show?

A

only actin

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

what does the A band show?

A

total width of myosin

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

what does the H zone show?

A

only myosin

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

what is the M line?

A

middle point of myosin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what is the Z line?

A

the point where actin filaments attach to each other

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

how do micrographs show thick and thin filament?

A

actin is paler and myosin is darker

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what happens to the I band during muscle contraction?

A

decreases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

what happens to the H zone during muscle contraction?

A

decreases

23
Q

what happens to the A band during muscle contraction?

A

nothing
- myosin isn’t moving

24
Q

what happens to the Z lines during muscle contraction?

A

they slide closer together, shortens the sarcomere

25
Q

describe the structure of slow twitch fibres

A
  • small diameter
  • contains a large store of myoglobin, rich blood supply and many mitochondria
  • red due to containing a lot of myoglobin
26
Q

where are slow twitch fibres located?

A

calf muscles

27
Q

what are the general properties of slow twitch fibres?

A
  • slower contraction
  • aerobic respiration for long periods of time due to rich blood supply and myoglobin O2 store
  • adapted for endurance work
28
Q

describe the structure of fast twitch fibres

A
  • larger diameter
  • more myosin filaments
  • large store of glycogen, store of phosphocreatine to help make ATP from ADP
  • high conc of enzymes involved in anaerobic respiration
29
Q

where are fast twitch fibres located?

A

biceps

30
Q

describe the general properties of fast twitch fibres

A
  • fast contraction
  • provides short bursts of powerful contraction
  • adapted for intense exercise
31
Q

explain why muscle fibres contain many mitochondria (2)

A
  • they produce ATP during aerobic respiration
  • ATP is needed to provide energy for muscle contraction
32
Q

suggest the advantage of having myoglobin in slow twitch muscle fibres (3)

A
  • acts as an oxygen store
  • allows muscle fibre to respire aerobically
  • even when blood can’t supply enough oxygen directly
33
Q

what is the sarcomere?

A

distance between 2 Z lines

34
Q

describe the structure of skeletal muscle (3)

A
  • made up of bundles of muscle fibres
  • each fibre made up of bundles of myofibrils
  • myofibrils made up of actin and myosin protein filaments
35
Q

name the protein present in the I band

A

actin

36
Q

name the proteins present in the A band

A

actin and myosin

37
Q

name the protein present in the H zone

A

myosin

38
Q

when the sarcomere contracts, what happens to the I, A and H band/zone?

A

I gets shorter
A stays the same
H gets shorter or disappears

39
Q

describe the role played by Ca2+ in the contraction of striated muscle (3)

A
  • released from sarcoplasmic reticulum
  • binds to troponin
  • troponin changes shape
  • tropomyosin moves so myosin binding site is exposed
  • myosin head binds to actin
40
Q

describe the role of ATP in muscle contraction

A
  • broken down by ATPase
  • provides energy to move myosin head which pulls actin filament
  • provides energy to break cross bridge so that myosin head detaches from actin
  • used up very quickly so has to be continuously generated
41
Q

describe aerobic respiration as energy production for muscle contraction

A
  • most ATP generated via oxidative phosphorylation in cell mitochondria
  • aerobic reps only works when oxygen is present
  • good for long periods of low intensity exercise
42
Q

describe aerobic respiration as energy production for muscle contraction

A
  • ATP is made rapidly by glycolysis
  • end product is pyruvate which is converted to lactate
  • lactate can quickly build up in muscles and cause muscle fatigue
  • good for short periods of intense exercise
43
Q

describe ATP CP system as energy production for muscle contraction

A
  • ATP is made by phosphorylating ADP
  • creatine phosphate is stored inside cells and the system generates ATP quickly
  • CP runs out after a few seconds
  • good for short bursts of vigorous exercise
  • anaerobic & lactic
44
Q

give one advantage and one disadvantage of generating ATP via the ATP creatine phosphate system

A

+ quick
+ used for short bursts of vigorous exercise
+ don’t require oxygen

  • not long lasting
45
Q

describe the function of skeletal muscle

A
  • contraction is controlled consciously
  • made of muscle fibres that contract quickly or slowly
46
Q

describe the structure of skeletal muscle

A
  • alternating shade colour stripes: A and I bands
  • long muscle fibres
  • many nuclei in each muscle fibre
47
Q

describe the function of smooth muscle

A
  • involuntary
  • controlled unconsciously
  • contract slowly
48
Q

describe the structure of smooth muscle

A
  • no striped appearance
  • found in the walls of hollow internal organs
  • one nucleus in muscle fibres
  • spindle shaped muscle fibres
49
Q

describe the function of the cardiac muscle

A
  • contracts on its own (myogenic)
  • pumps blood around the body
  • contract rhymically and don’t fatigue
50
Q

describe the structure of the cardiac muscle

A
  • found in heart walls
  • made of muscle fibres connected by intercalated discs
  • low electrical resistance so nerve impulses pass easily between cells
  • muscle fibres are branched to allow nerve impulses to spread quickly
  • each cardiac muscle has 1 nucleus
  • muscle fibres are shaped like cylinders
51
Q

describe the similarities between all 3 muscle types

A
  • contains actin and myosin which interact to bring about contraction
  • antagonistic pairs ( eg one contracts whilst other elongates)
52
Q

what is an EMG?

A

electromyogram

53
Q

what does an EMG look at?

A

electrical impulses to muscles
- motor neurone activity

54
Q

how does an EMG work?

A
  • electrical signals in muscles can be detected by electrodes on the skin
  • electrodes connected to a computer

Biology 5.1.5: Animal Responses (6 decks)

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