Structure Of Muscle Fibre

Question 1

Structure of a Muscle Fibre

Answer 1

Muscle Fibre-Mycofibrils-Sacromeres (repeated contractile units)-Protein filaments (Actin and Myosin)

Question 2

What are Slow Twitch Fibres specialised for?

Answer 2

Slow sustained muscle contraction

Question 3

What are Fast Twitch Fibres specialised for?

Answer 3

Rapid intense muscle contraction

Question 4

Slow Twitch

Answer 4

1. High levels of protein Mycoglobin which gives characteristic dark red pigment. Acts as an oxygen store only releasing oxygen when there are low concentrations.
2. Lots of capillaries ensuring good oxygen supply
3. Lots of mitochondria
4. High levels of aerobic respiration enzymes
5. Fatigue resistant
6. Little sacroplasmic reticulum
7. Low glycogen content

Question 5

Fast Twitch

Answer 5

1. White muscle little myoglobin
2. Little mitochondria
3. Few capillaries
4. High glycogen content
5. Fatigue easily
6. Extensive sacroplasmic reticulum

Dependence of anaerobic respiration means that rapid release of lactic acid therefore muscle fibres fatigue easily