Topic 6 Skeletal Muscle Fiber types

Question 1

RE. Skeletal muscle types, not all skeletal muscle fibres are the same - differences include (3)

Answer 1

the speed which they generate tension
how they use different energy substrates
how they fatigue

Question 2

There are 3 main types of skeletal muscle fibre

Answer 2

1) Slow oxidative
2) Fast Oxydative-Glycolytic (FOG)
3) Fast Glycolytic

Question 3

True/False
The forcefulness of contraction (ability to generate force) depends on the length of the sarcomeres within a muscle BEFORE the contraction begins

Answer 3

True

Question 4

Greatest ability to generate tension

Answer 4

Optimal overlap (resting tension)
***Mid range - greatest capacity to generate force

Question 5

Decreased ability to generate tension - 1

Answer 5

Minimal overlap (lengthening)

Question 6

Decreased ability to generate tension - 2

Answer 6

Excessive overlap

Question 7

Types of contractions…

muscle contraction through a range against a resistance that is not changing

Answer 7

Isotonic

Iso=Same Tonic=Assistance

Question 8

Types of contractions…

a shortening contraction

Answer 8

Concentric

Question 9

Types of contractions…

a lengthening contraction

Answer 9

Eccentric

Question 10

Types of contractions…

muscle contraction which the length of the muscle does not visibly change

Answer 10

Isometric

Iso=Same Metric=Measurement

Question 11

Types of contractions… NEW

muscle contraction through a range in which equipment varies the resistance to match the length of the curve

Answer 11

Variable resistance

Question 12

Types of contractions… NEW

muscle contraction through a range in which equipment keeps the same velocity of movement constant

Answer 12

Isokinetic

Iso=same Kinetic=Movement

Question 13

Re. muscle tone…
a small amount of tension being generated in the muscle;
not strong enough to produce motion

Answer 13

Resting tone

*resistance in tissue

Question 14

muscle term

a brief contraction of all the muscle fibres in a motor unity in response to a single AP in its motor neuron

Answer 14

Twitch contaction

*single motor unit level - usually

Question 15

muscle term

a lack of tone from the nerve being damaged or cut

Answer 15

Flaccidity

*nerve has reconnected if you see a twitch during rehab

Question 16

muscle term

increase in muscle size

Answer 16

Hypertrophy

*muscle growth

Question 17

muscle term

decrease in muscle size

Answer 17

Atrophy

*decrease in muscle size

Question 18

Types of muscle fatigue (5)

Answer 18

1) inability of a muscle to function at the required level
2) energy substrate depletion
3) metabolic by-products (eg. heat interfering with muscle performance
4) neurological fatigue (eg physiology - overworked muscles)
5) central nervous system fatigue (eg Drive/ motivation is affected depression - speaks to motivation)

Question 19

Re. muscle regeneration…
They are undifferentiated muscle cells;
actively involved in muscle repair and regeneration;
capacity is limited

Answer 19

Satellite cells

*stem cells for muscles

Question 20

Re. muscle connective tissue…

it surrounds the entire muscle

Answer 20

Epimysium

Question 21

Re. muscle connective tissue…

it surrounds the fascicles

Answer 21

Perimysium

Question 22

Re. muscle connective tissue…

it surrounds the muscle fibre

Answer 22

Endomysium

Question 23

Tendons are an extension of muscle cells
eg. the epimysium, perimysium, endomysium are all interconnected;

They extend beyond the muscle fibres to connect the muscle to the periosteum (or other structures)

Answer 23

these connections are known as junctions

Question 24

The transition from muscle tissue to tendon

Answer 24

musculotendendinous junction

Question 25

The transition from tendon to periosteum

Answer 25

tendoperiosteal junction

Question 26

Its known as a 'broad, flat, tendon

Answer 26

Aponeurosis

Question 27

A tube that surrounds a tendon to protect it

Answer 27

Tendon sheath

Question 28

Type of muscle... > Same actin/ myosin arrangement as skeletal muscle; > Fibres are branched - the ends are fit tightly together with neighbouring fibres called intercalated discs; > Anchoring junctions hold them together; > Gap junctions allow for cells to communicate quickly > involuntary control (electric synaps)

Answer 28

Cardiac muscle

Question 29

Re. Autorythmicity... What type of muscle has specialized cells that can generate their own electric signals; They act as a pacemaker

Answer 29

Cardiac muscle

Question 30

``` Type of muscle... > Found in the walls of hollow tubes; > Spindle shaped > have gap junctions > involuntary control > contractions start slowly and last longer ```

Answer 30

Smooth muscle

Question 31

Smooth muscle has 2 types of tissue ?

Answer 31

1) single unit smooth muscle tissue | 2) multi unit smooth muscle tissue

Question 32

Type of smooth muscle tissue... One AP supplies smooth muscle fibres... > Via gap junctions, they operate as a single unit; > walls of small arteries, hollow organs

Answer 32

single unit smooth muscle tissue

Question 33

Type of smooth muscle tissue... One motor neuron terminal supplies one smooth muscle muscle fibre > Via few gap junctions; > Walls of large arteries, airways in lungs, erector pilli, muscle of iris

Answer 33

multi unit smooth muscle tissue