Brainscape's Knowledge GenomeTM

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


See full index

PE- phis > The Phisiology Of Skeletal Muscle > Flashcards

The Phisiology Of Skeletal Muscle Flashcards

1
Q

The Sliding Filament Theory

A

1- Preparing Binding Site

  • action potential allows for the sarcoplasm in reticulum to release calcium ions
  • ions bind to troponin in which pulls tropomyosin exposing the myosin

2- The Power Stroke

  • cross bridge created
  • when binded to myosin head it pulls the actin filament towards sarcomere centre

3- The Binding Site

  • ATP re energises the myosin head
  • myosin filament uncouple from the actin filament

4) The Ratchet Mechanism
- sufficient calcium is needed
- myofibril gets smaller
- h zone disappears

5) Return Of Calcium
- calcium ions return to sarcoplasmic reticulum
- troponin shape changes

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

Actin

A
  • the thin protein filament sound in the muscle cells that together with myosin form sarcomeres, the contrachle units of the skeletal muscle
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Myosin

A
  • the thick protein filament that together with actin form sarcomeres the contractile units of the skeletal muscle
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Troponin

A
  • a calcium receptor that sits on the top of troponin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Tropomyosin

A
  • spirals that wrap around the actin filament which covers the myosin binding site which prevents myosin attachment during relaxed state
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

The structure of the skeletal muscle

A
  • the muscle belly is wrapped in a thick tissue that allows for movement of muscles and carries the epimysium
  • perimysium surrounds bundles of muscle fibres named fasciculi
  • endomysium surrounds each individual fibre
  • each of them extend to form tendons
  • muscle fibres are made of of hundreds of myofibrils
  • these contain actin and myosin which allow for energy production and the control of the movement
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

SFT- Step 1- preparing the binding site

A
  • troponin pulls tropomyosin away form the binding site
  • sarcoplasmic reticulum releases calcium ions
  • troponin and tropomyosin are found on the actin filament
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

SFT- Step 2- Power Stroke

A
  • myosin head attaches to actin filament
  • myosin head pulls the actin filament towards the centre of the sarcomere
  • myosin head is thick
  • actin filament is thin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

SFT- Step 3- binding ATP

A
  • ATP releases energy
  • energy allows the myosin to pull the actin filament inwards and so shortening the muscle
  • how is the ATP binding site exposed for re energising? Myosin filament uncoupled from actin filament allowing ATP to bind onto it- returning the myosin back to re energising state
  • H zone gets smaller as the muscle contracts
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

STF- Step 4- ratchet mechanism

A
  • myosin detaches from the actin
  • sarcomere length gets smaller as well as the the myofibril
  • sarcoplasmic reticulum keeps releasing calcium ions and the H zone eventually disappears
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

SFT- Step 5- return of calcium

A
  • calcium leave the myosin binding site as their is no actin potential
  • calcium ions go to the sarcoplasmic reticulum
  • muscles become relaxed
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Slow Twitch Muscle Fibres (type 1)

A
  • they contract more slowly but are highly resistant to fatigue
  • favoured by endurance athletes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Fast Twitch Muscles Fibres (type 2)

A
  • they contract more rapidly generating greater forces but are more liable to fatigue
  • favoured by sprinters and power athletes

The 2 types

1) type 2b- fast oxidative glycolytic- they are more resistant to fatigue
2) type 2b- fast twitch glycolytic- greater anaerobic capacity

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

Slow Twitch characteristics

A

Speed of contraction- slow

Force of contraction- low

Resistance to fatigue- very high

Aerobic capacity- very high

Anaerobic capacity- low

Fibre size- small

Mitochondrial density- high

Capillary density- high

Myoglobin content- high

PC store- low

Glycogen store- low

Triglyceride store- high

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

Fast twitch- type 2a characteristics

A

Speed of contraction- fast

Force of contraction- high

Resistance to fatigue- moderate

Aerobic capacity- moderate

Anaerobic capacity- high

Fibre size- large

Mitochondrial density- moderate

Capillary density- moderate

Myoglobin content- moderate

PC store- high

Glycogen store- high

Triglyceride store- moderate

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

Fast twitch- type 2b characteristics

A

Speed of contraction- fast

Force of contraction- highest

Resistance to fatigue- low

Aerobic capacity- low

Anaerobic capacity- high

Fibre size- large

Mitochondrial density- low

Capillary density- low

Myoglobin content- low

PC store- high

Glycogen store- high

Triglyceride store- low

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

Muscle fibre recruitment

A
  • each muscle fibre within the muscle belly is supplied by only one motor neuron but can innervate anything from just a few fibres into several hundred
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Motor Unit

A
  • it’s a basic functional unit of skeletal muscle
  • it is the motor nerve and group of muscle fibres it controls
  • stimulation of one motor neurone causes all the muscle fibres in that motor unit to contract simultaneously
  • each individual muscle will be made up of motor units
  • the amount of motor units recruited depends on the amount of strength required for a given movement
  • greater strength= more motor units
  • motor units are usually made up of the same muscle fibre type
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

The All or None Law

A
  • muscle fibres within a motor unit contract fully or not at all
  • they can not partially contract
  • a minimum stimulation is needed for the muscle to contract- if this threshold is reach all will contract
  • if it falls short of the threshold then the muscle fibres do not respond and muscular contraction fails to occur
20
Q

Spatial Summation- an increase in responsiveness of a nerve resulting from the additive effect of numerous stimuli

A
  • for a muscle to contract the EPSP must be of a certain level of intensity to intimate the sliding filament mechanism
  • spatial summation describes the progressive increase in the size of the EPSP as a result of the arrival of a number of impulses at the synaptic cleft if individual fibres
21
Q

With reference to the Sliding Filament Hypothesis, explain the roles of tropomyosin and troponin during muscle contraction. (4 marks)

A

A. Tropomyosin prevents myosin attaching to actin filaments
B. Nerve impulse/electrical impulse/action potential
C. Releases calcium ions (from sarcoplasmic reticulum)
D. (Calcium ions) attach to troponin (on actin filaments)
E. Causing shape of troponin to alter/moves out of the way
F. Tropomyosin binds to actin/winds around/neutralises the troponin
G. Exposes myosin binding site (on actin filament)
H. Allows myosin to bind to actin/cross-bridges formed

22
Q

Explain how actin and myosin filaments in the sarcomere bind together during muscular contraction. (4 marks)

A

A. Filaments unable to bind due to tropomyosin
B. Receipt of nerve impulse/action potential/electrical impulse/wave of
depolarisation
C. Sarcoplasmic reticulum (releases)
D. Calcium (ions released)
E. (Calcium) Attach to troponin (on actin filaments)
F. Causes change of shape of troponin/moves tropomyosin
G. Exposes myosin binding site (on actin filament)/ ATP
H. Cross bridge formation
I. Powerstroke occurs/Ratchet Mechanism/Reduce H zone/z lines
closer together

23
Q

How can a performer vary the strength of muscular contractions to ensure that a skill is completed correctly? (4 marks)

A

A. (Greater the force needed) larger motor units recruited
B. More units recruited
C. Need fast twitch fibres rather than slow twitch fibres
D. Multiple unit summation/spatial summation
E. All or none law/All or nothing law/or explanation
F. Wave summation/frequency of impulse/innervations
G. Motor unit unable to relax/increase the force
H. Tetanus/titanic for powerful contraction
I. Muscle spindles detect changes in muscle length/speed of contraction
J. Send information to brain/CNS
K. Compares information to long term memory to ensure correct force applied/past
Experiences
L. Spatial summation – rotating the frequency of the impulse to motor units to delay fatigue

24
Q

Describe the characteristics of the main muscle fibre type used by elite sprinters. (4 marks)

A
  1. Fast contracting
  2. High force production/more powerful
  3. Low lactate/fatigue tolerance/lactate threshold
  4. Larger/faster motor neurone
  5. High sarcoplasmic reticulum development
  6. More/thicker myosin/larger/bigger diameter
  7. High PC stores/levels of creatine kinase
  8. High glycogen stores
  9. High glycolytic/anaerobic/ATPase enzyme capacity
25
Q

It has been suggested that performers should be screened or tested to establish the proportions of different muscle-fibre types before deciding which activity to concentrate on.

Discuss whether such tests should be the only consideration when choosing an activity. (4 marks)

A
  1. Fast-twitch for speed/anaerobic or strength/slow-twitch for stamina/aerobic;
  2. Proportions inherited;
  3. Unaffected by training;
  4. But many other factors involved in activities e.g. skills/techniques;
  5. e.g. Length of levers in sprinting;
  6. e.g. VO2 max in stamina-based activities;
  7. Two suitable examples of other factors such as fitness, ability,
    physique/frame size etc.
26
Q

What do you understand by the term motor unit? (2 marks)

A
  1. Motor neurone and muscle fibres;
  2. All fast-twitch or slow-twitch/ homogenous;
  3. All or none law.
27
Q

How are motor units involved in the process of spatial summation? (2 marks)
(

A

a) (iii) 1. (Spatial summation) – Increased strength/more force in muscles;
2. Use bigger/larger motor units;
3. More motor units;
4. Fast-twitch units produce more force than slow-twitch units. 2 marks
(ii) Contraction of different types of muscle fibres involves the use of motor units.

28
Q

What are the characteristics of the type of muscle fibres used to produce maximal contractions? (6 marks)

A
  1. Fast-twitch (glycolytic) fibres/type 2b;
  2. Fast motor neurone conduction velocity;
  3. Large muscle fibre diameter;
  4. More sarcoplasmic reticulum development;
  5. Low mitochondrial density;
  6. Low capillary density;
  7. Low myoglobin content;
  8. High PC stores;
  9. High glycogen stores;
  10. Low triglyceride stores;
  11. High myosin ATPase / glycolytic enzyme activity;
  12. Low oxidative enzyme activity;
  13. Fast contraction / relaxation time;
  14. High force production/more powerful;
  15. Low fatigue resistance.
29
Q

Explain how the muscle spindle apparatus may be used to adjust the strength of a muscle contraction. (3 marks)

A
  1. Muscle spindles are (stretch) receptors/propriocepters;
  2. Force/resistance causes contraction or stretching of a muscle detected by muscle spindles;
  3. Results in sensory impulses going to brain/spinal cord/CNS concerning state of contraction;
  4. Muscle pre-sets tension based on information held in memory;
  5. Gamma bias;
  6. Tension adjusted through feedback of information to brain;
  7. Gamma neurones activate spindle/intrafusal fibres;
  8. Recruit more/bigger motor units;
30
Q

The player in Figure 4 is preparing to catch the ball. Explain the role of muscle spindles in the action of catching the ball. (3 marks)

A

A. Changes to contraction/lengthening/shortening/stretch in muscle detected by spindles/intrafusal fibres;
B. Sensory nerve impulses to brain/spinal cord/CNS;
C. Body awareness/kinesthesis/position of arms set;
D. Spindles pre-set tension in muscles/muscle loading;
E. Uses memory/experience; (E must be linked to D to credit)
F. Gamma bias (

31
Q

Identify five structural and/or physiological differences between fast and slow-twitch muscle fibres. (5 marks)

A
  1. Fast-twitch have – faster contractions/twitches/faster (myosin) ATPase;
  2. More PC;
  3. Lower lactate tolerance/fatigue easily;
  4. More glycogen;
  5. More anaerobic enzymes/greater capacity;
  6. Less mitochondria;
  7. Less myoglobin;
  8. More oxidative enzymes/lower oxidative capacity;
  9. More force/strength/powerful contractions;
  10. More sarcoplasmic rectilium;
  11. Larger motor neurone/(motor) unit/fibre diameter.
32
Q

Suggest three possible physiological causes of muscle fatigue. (3 marks)

A
  1. Lack of PC;
  2. Lactate/lactic acid build up/OBLA;
  3. Increase acidity/lowering pH/increase H+concentration;
  4. Effect on enzymeds/actin/PFK;
  5. Lack of calcium ions;
  6. Glycogen depletion;
  7. Acetylcholine depletion;
  8. Dehydration/electrolyte depletion;
  9. Muscle wisdom/less impulses sent from brain.
33
Q

With reference to the Sliding Filament Hypothesis, explain the roles of tropomyosin and troponin during muscle contraction. (4 marks)

A

A. Tropomyosin prevents myosin attaching to actin filaments
B. Nerve impulse/electrical impulse/action potential
C. Releases calcium ions (from sarcoplasmic reticulum)
D. (Calcium ions) attach to troponin (on actin filaments)
E. Causing shape of troponin to alter/moves out of the way
F. Tropomyosin binds to actin/winds around/neutralises the troponin
G. Exposes myosin binding site (on actin filament)
H. Allows myosin to bind to actin/cross-bridges formed

34
Q

Explain how actin and myosin filaments in the sarcomere bind together during muscular contraction. (4 marks)

A

A. Filaments unable to bind due to tropomyosin
B. Receipt of nerve impulse/action potential/electrical impulse/wave of
depolarisation
C. Sarcoplasmic reticulum (releases)
D. Calcium (ions released)
E. (Calcium) Attach to troponin (on actin filaments)
F. Causes change of shape of troponin/moves tropomyosin
G. Exposes myosin binding site (on actin filament)/ ATP
H. Cross bridge formation
I. Powerstroke occurs/Ratchet Mechanism/Reduce H zone/z lines
closer together

35
Q

How can a performer vary the strength of muscular contractions to ensure that a skill is completed correctly? (4 marks)

A

A. (Greater the force needed) larger motor units recruited
B. More units recruited
C. Need fast twitch fibres rather than slow twitch fibres
D. Multiple unit summation/spatial summation
E. All or none law/All or nothing law/or explanation
F. Wave summation/frequency of impulse/innervations
G. Motor unit unable to relax/increase the force
H. Tetanus/titanic for powerful contraction
I. Muscle spindles detect changes in muscle length/speed of contraction
J. Send information to brain/CNS
K. Compares information to long term memory to ensure correct force applied/past
Experiences
L. Spatial summation – rotating the frequency of the impulse to motor units to delay fatigue

36
Q

Describe the characteristics of the main muscle fibre type used by elite sprinters. (4 marks)

A
  1. Fast contracting
  2. High force production/more powerful
  3. Low lactate/fatigue tolerance/lactate threshold
  4. Larger/faster motor neurone
  5. High sarcoplasmic reticulum development
  6. More/thicker myosin/larger/bigger diameter
  7. High PC stores/levels of creatine kinase
  8. High glycogen stores
  9. High glycolytic/anaerobic/ATPase enzyme capacity
37
Q

It has been suggested that performers should be screened or tested to establish the proportions of different muscle-fibre types before deciding which activity to concentrate on.

Discuss whether such tests should be the only consideration when choosing an activity. (4 marks)

A
  1. Fast-twitch for speed/anaerobic or strength/slow-twitch for stamina/aerobic;
  2. Proportions inherited;
  3. Unaffected by training;
  4. But many other factors involved in activities e.g. skills/techniques;
  5. e.g. Length of levers in sprinting;
  6. e.g. VO2 max in stamina-based activities;
  7. Two suitable examples of other factors such as fitness, ability,
    physique/frame size etc.
38
Q

What do you understand by the term motor unit? (2 marks)

A
  1. Motor neurone and muscle fibres;
  2. All fast-twitch or slow-twitch/ homogenous;
  3. All or none law.
39
Q

How are motor units involved in the process of spatial summation? (2 marks)
(

A

a) (iii) 1. (Spatial summation) – Increased strength/more force in muscles;
2. Use bigger/larger motor units;
3. More motor units;
4. Fast-twitch units produce more force than slow-twitch units. 2 marks
(ii) Contraction of different types of muscle fibres involves the use of motor units.

40
Q

What are the characteristics of the type of muscle fibres used to produce maximal contractions? (6 marks)

A
  1. Fast-twitch (glycolytic) fibres/type 2b;
  2. Fast motor neurone conduction velocity;
  3. Large muscle fibre diameter;
  4. More sarcoplasmic reticulum development;
  5. Low mitochondrial density;
  6. Low capillary density;
  7. Low myoglobin content;
  8. High PC stores;
  9. High glycogen stores;
  10. Low triglyceride stores;
  11. High myosin ATPase / glycolytic enzyme activity;
  12. Low oxidative enzyme activity;
  13. Fast contraction / relaxation time;
  14. High force production/more powerful;
  15. Low fatigue resistance.
41
Q

Explain how the muscle spindle apparatus may be used to adjust the strength of a muscle contraction. (3 marks)

A
  1. Muscle spindles are (stretch) receptors/propriocepters;
  2. Force/resistance causes contraction or stretching of a muscle detected by muscle spindles;
  3. Results in sensory impulses going to brain/spinal cord/CNS concerning state of contraction;
  4. Muscle pre-sets tension based on information held in memory;
  5. Gamma bias;
  6. Tension adjusted through feedback of information to brain;
  7. Gamma neurones activate spindle/intrafusal fibres;
  8. Recruit more/bigger motor units;
42
Q

The player in Figure 4 is preparing to catch the ball. Explain the role of muscle spindles in the action of catching the ball. (3 marks)

A

A. Changes to contraction/lengthening/shortening/stretch in muscle detected by spindles/intrafusal fibres;
B. Sensory nerve impulses to brain/spinal cord/CNS;
C. Body awareness/kinesthesis/position of arms set;
D. Spindles pre-set tension in muscles/muscle loading;
E. Uses memory/experience; (E must be linked to D to credit)
F. Gamma bias (

43
Q

Identify five structural and/or physiological differences between fast and slow-twitch muscle fibres. (5 marks)

A
  1. Fast-twitch have – faster contractions/twitches/faster (myosin) ATPase;
  2. More PC;
  3. Lower lactate tolerance/fatigue easily;
  4. More glycogen;
  5. More anaerobic enzymes/greater capacity;
  6. Less mitochondria;
  7. Less myoglobin;
  8. More oxidative enzymes/lower oxidative capacity;
  9. More force/strength/powerful contractions;
  10. More sarcoplasmic rectilium;
  11. Larger motor neurone/(motor) unit/fibre diameter.
44
Q

Suggest three possible physiological causes of muscle fatigue. (3 marks)

A
  1. Lack of PC;
  2. Lactate/lactic acid build up/OBLA;
  3. Increase acidity/lowering pH/increase H+concentration;
  4. Effect on enzymeds/actin/PFK;
  5. Lack of calcium ions;
  6. Glycogen depletion;
  7. Acetylcholine depletion;
  8. Dehydration/electrolyte depletion;
  9. Muscle wisdom/less impulses sent from brain.
45
Q

What are the characteristics of the type of muscle fibres used to produce maximal contractions? (6 marks)

A
  1. Fast-twitch (glycolytic) fibres/type 2b;
  2. Fast motor neurone conduction velocity;
  3. Largemusclefibrediameter;
  4. More sarcoplasmic reticulum development;
  5. Low mitochondrial density;
  6. Low capillary density;
  7. Low myoglobin content;
  8. High PC stores;
  9. High glycogen stores;
  10. Low triglyceride stores;
  11. High myosin ATPase / glycolytic enzyme activity;
  12. Low oxidative enzyme activity;
  13. Fast contraction / relaxation time;
  14. High force production/more powerful;
  15. Low fatigue resistance.
46
Q

Explain how the muscle spindle apparatus may be used to adjust the strength of a muscle contraction. (3 marks)

A
  1. Muscle spindles are (stretch) receptors/propriocepters;
  2. Force/resistance causes contraction or stretching of a muscle detected by muscle
    spindles;
  3. Results in sensory impulses going to brain/spinal cord/CNS concerning state of
    contraction;
  4. Muscle pre-sets tension based on information held in memory;
  5. Gamma bias;
  6. Tension adjusted through feedback of information to brain;
  7. Gamma neurones activate spindle/intrafusal fibres;
  8. Recruit more/bigger motor units;

PE- phis (5 decks)

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