4- Muscle Structure And Adaption

Question 1

How are skeletal muscle fibres classified and what are these classificatioms?

Answer 1

They are classified into 2 main groups according to contraction speed
Theses are :
- slow twitch fibres (typeI)
- fast twitch fibres (typeII)

Question 2

What are the features of slow twitch fibres (type I)?

Answer 2

• fatigue resistant
• moderate max force
• oxidative metabolism
• many mitochondria
• rich vascularisation
• small diameter
• high myoglobin (red muscle)

Question 3

What are the features of fast twitch fibres (type II)?

Answer 3

• fatigue rapidly
• high max force
• can have glycolic or mixed with oxidative metabolism
• fewer mitochondria
• sparser vascularisation
• larger diameter
• low myoglobin (white muscle)

Question 4

What controls force generation in a muscle?

Question 5

What does a motor unit contain?

Question 6

What is summation?

Question 7

What is glycolysis?

Question 8

How does the diameter of the muscle fibre influence the level of peak force generated in fast and slow-twitch muscle fibres?

Question 9

What is myoglobin?
and
What is the function of myoglobin in muscle ?

Question 10

Why do slow-twitch muscle fibres have a higher capacity for oxidative metabolism?

Question 11

Explain the reddish appearance of type I muscle fibres

Question 12

Why is type II muscle more paler in appearance?

Question 13

What can cause variation in the colour of mammalian muscle?
and
Why are the terms “red muscle” and “white muscle” misleading in humans and mammals?

Question 14

What is oxidative metabolism?

Question 15

Which is faster, and which produces more ATP: glycolysis or oxidative metabolism?

Question 16

What are three factors that will determine the max force in the muscle fibre?

Question 17

What do the isoforms of the myofibril proteins of a muscle fibre impact?

Question 18

How does sarcomere structure vary between muscle fibres

Question 19

State two ways in which variation in the isoforms of the myofibril proteins can influence the rate and strength of contraction

Question 20

How do isoforms of myosin heavy chain (MHC) influence the rate and strength of contraction?

Question 21

Which isoforms of myosin heavy chain (MHC) are expressed in fast-twitch and slow-twitch muscle fibres?

Question 22

How is the funciton of a muscle determined?

Question 23

What muscle fibre type is the laterial rectus composed of and why?

Question 24

What is the gastrocnemius muscle?

Question 25

What muscle fibre type is the gastrocnemius muscle composed of and why?

Question 26

Which muscle fibre type is required for powerful movements that occur in bursts (i.e. jumping, sprinting etc.) and why?

Question 27

How does the proportion of fast and slow twitch muscle fibres vary between untrained individuals, endurance athletes, and sprinters?

Question 28

Why do endurance athletes need a high proportion of slow-twitch fibres?

Question 29

Why do sprinters need a high proportion of slow-twitch fibres?

Question 30

How can the proportion of fast and slow-twitch muscle fibres change through changing?

Question 31

How does resistance training increase the porportion of fast-twitch muscle fibres?

Question 32

What is muscle hypertrophy?

Question 33

What is “activity pattern”?

Question 34

How does sustained calcium release during prolonged activity increase the expression of slow-twitch fibres?

Question 35

What is the name of the mechanism involved in controlling the generation of force produced by a muscle?