Key Area 8 Flashcards
What happens to muscle cells during vigorous exercise?
They do not get sufficient oxygen
What happens under these conditions?
Pyruvate is converted to lactate
What does the conversion of pyruvate to lactate involve?
The transfer of hydrogen ions from the NADH produced during glycolysis to pyruvate in order to produce lactate
What happens when lactate accumulates?
muscle fatigue occurs
What builds up?
An oxygen debt
What is regenerated as lactate is produced?
NAD
Why is NAD needed?
To maintain ATP production through glycolysis
What happens when exercise is complete?
The oxygen debt is repaid and aerobic respiration can occur again
What is energy from aerobic respiration used for?
converting lactate back to pyruvate
What are the 2 main types of skeletal muscle fibre?
Slow twitch
Fast twitch
Give 5 characteristics of Slow twitch muscle fibres
- contract relatively slowly
- can sustain contractions for longer than FTMF
- Rely on aerobic respiration to generate ATP
- Have many mitochondria
- Have a large and good blood supply
- Have a high concentration of an oxygen storing
protein called myoglobin - Major fuel store is fat
- Useful for endurance activities such as long distance
running
Give 5 characteristic of Fast Twitch Muscle Fibres
- Contract relatively quickly
- Can sustain contraction over short periods of time
- Generate ATP through glycolysis only
- Have fewer mitochondrion that STMF
- Have a lower blood supply that STMF
- Major fuel store is glycogen
- Useful for activities such a sprinting or weightlifting
What do most human tissues contain?
A mixture of STMF and FTMF
What do athletes show?
A distinct pattern of muscle fibres reflecting their sporting activity
