Skeletal muscle fibre types

Question 1

Skeletal muscles are under what kind of control by the body?

Answer 1

conscious

Question 1

The skeletal muscles are the only type to play a significant role in what kind of body movement?

Answer 1

voluntary

Question 2

Skeletal muscle contains several types of fibre. Although other fibres operate between these two extremes, what are the main two types?

Answer 2

Fast and slow twitch fibres

Question 3

What are the 3 types of muscle?

Answer 3

skeletal, cardiac and smooth

Question 4

What colour are slow twitch fibres and why? (3)

Answer 4

red
1. because they have a high myoglobin content (a red-coloured protein)
2. narrower diameters and
3. are surrounded by blood capillaries.

Question 5

Slow twitch muscles fibres are also known as what?

Answer 5

slow oxidative (type I) fibres

Question 6

Do slow twitch muscle fibres favour aerobic metabolism or anaerobic?

Answer 6

aerobic

Question 7

What do slow twitch fibres use to provide energy for the muscles?

Answer 7

they use oxygen to provide energy for the muscle cells.

Question 8

Slow twitch muscle fibres contain many structures responsible for the production of energy known as what?

Answer 8

mitochondria

Question 9

Slow twitch muscle fibres are very resistant to what in relation to exercise?

Answer 9

fatigue

Question 10

Where can slow twitch muscle fibres be found in large numbers?

Answer 10

postural muscles.

Question 11

Give some examples of when slow twitch fibres are activated

Answer 11

in endurance activities such as long-distance running.

Question 12

There are two types of fast twitch fibres, these are?

Answer 12

fast oxidative (type IIa) fibres and fast glycolytic (type IIb) fibres

Question 13

In terms of structure, how do fast twitch fibres differ from slow twitch?

Think
1. size
2. amount of capillaries
3. colour
4. myoglobin content

Answer 13

1. greater in size
2. have a less generous supply of capillaries
3. are white or pale pink
4. lower myoglobin content.

Question 14

Do fast twitch fibres favour aerobic or anaerobic systems and why (in relation to energy/ mitochondria)

Answer 14

anaerobic - they rely less on oxygen supply for their energy and have fewer mitochondria

Question 15

Which of the two fast twitch muscle fibres are the most aerobic and have the capability of working both aerobically and anaerobically.

Answer 15

Type IIa fibres

Question 16

Which of the two fast twitch fibres have are more anaerobic and have relatively little aerobic capability?

Answer 16

Type IIb fibres

Question 17

Give an example of when fast twitch fibres are used in relation to exercise?

Answer 17

Fast twitch fibres are used more in fast, short-term activities like sprinting, although they are also important in stop-and-go activities such as football or basketball.

Question 18

What are some other factors that play into whether or not you have more fast or slow twitch fibres

Answer 18

Heredity - Your body may be better suited to either endurance-type activities or explosive-type activities depending to a large extent on how well you have chosen your parents and grandparents!

Question 19

In relation to childhood what may determine whether or not you have more slow or fast twitch fibres?

Answer 19

It certainly seems to be true that training in adulthood has no effect on muscle fibre type, although training in childhood may possibly do so.

Question 20

When a single muscle fibre is viewed under a microscope, it can be seen to contain 1,000 or more long, thin strings, arranged in bundles along the length of the fibre. These are called?

Answer 20

myofibrils

Question 21

The web like structure surrounding the myofibrils is the?

Answer 21

sarcoplasmic reticulum

Question 22

Myofibrils are separated into segments that are composed of tiny filaments of protein called?

Answer 22

sarcomeres

Question 23

The protein filaments in each myofibril are called? (2)

Answer 23

myosin and actin