Muscle fibres and energy sources Flashcards
(8 cards)
what are the two types of muscle fibres ?
type 1 (slow twitch)
tpye 2 (fast twitch)
the types of muscle fibres a person have depend on 3 factors
- genetics
- training
- type of muscles
explain type 1 fibres
aerobic = oxidative phosphorolation
- continuous exercise like marathons
- continuous and slow muscle contraction
- dark in colour because of rich blood supply and high myoglobin
- lots of mitochondria, capilleries and myoglobin
- low resistance to lactic acid
- small diameter of fibres
explain type 2 fibres
anaerobic = glycolysis to synthesis ATP
- short bursts of strength and speed e.g. jumping
- contract then relax rapidly, contract quickly and fatigue rapidly
- few mitochondria
- anaerobic respiration
- low capilaries
- high glycogen stores
- light in colour due to little blood supply and low myoglobin concentration
- low myoglobin
- larger diameter of fibres
whats the first energy store used
ATP-PC when oxygen is limited less ATP is made by oxidative phosphorolation in the mitochondria. creatine phosphate + ADP ↔️ creatine + ATP. The phospate is transfered to ADP to maintain ATP levels, this reaction can continue untill all creatine phosphate has been used up.
10-12 seconds duration.
what is the second energy store used?
anaerobic respiration (lactic acid system), when ATP-PC is depleted. Glycolysis of glucose produced 2 ATP + lactate
- lactate causes muscle fatigue and needs to be removed, it goes to the liver in the bloodstream and is converted to pyruvate when oxygen is available = O2 dept = increased ventilation, breathe depth, HR and stroke volume
whats the 3rd energy store ?
aerobic respiration, 1 glucose produces 34 ATP, glycolysis, link reaction, Krebs cycle and electron transport chain (oxidative phosphorolation)
what is carbohydrate loading?
a method used by endurance athletes to delay fatigue and compete for longer before hitting the wall
- ‘hitting the wall’ is when glycogen stores are depleted
