3.2. Respiratory System 2 Flashcards
Association
When O2 combines with haemoglobin through diffusion at the lungs to give oxyhaemoglobin
Dissociation
When O2 releases from haemoglobin through diffusion at the muscles
Oxyhaemoglobin dissociation curve
Shows us the relationship between PPO2 and % saturation of haemoglobin
Oxyhaemoglobin dissociation curve at rest
- At the lungs, haemoglobin is 100% saturated with O2
- At the muscles, haemoglobin in 75% saturated with O2
- So at rest, 25% of O2 dissociated with haemoglobin and diffuses into muscle
What happens to the curve as intensity increases?
Shifts to right
Why does the curve shift to the right- oxygen?
- Muscles are using more O2 so decreased PPO2 inside muscle
- There is a steeper diffusion gradient between blood and muscle
- Causes more O2 to dissociate from haemoglobin
Why does the curve shift to the right- Co2?
- Muscles are producing more Co2 so increased PPCo2 inside muscle
- There is a steeper diffusion gradient between muscle and blood
- Causes more Co2 to diffuse into blood
Why does the curve shift to the right- body temp?
Body temp increases which makes O2 dissociate from haemoglobin more readily
Why does the curve shift to the right- acidity?
- Lactic acid and carbonic acid increase acidity which makes O2 dissociate from haemoglobin more readily
- When an increased acidity causes the oxyhaemoglobin curve to shift to the right it’s called the Bohr Shift
Average breathing frequency at rest
12 breath per min
Average TV at rest
0.5L
Average VE at rest
6L/min
Breathing frequency for an endurance athlete at rest
10 breaths per min
TV for an endurance athlete at rest
0.5L/min
VE for endurance athlete at rest
5L/min
Average breathing frequency at maximal
50 breaths per min
Average TV at maximal
2.5L
Average VE at maximal
125L/min
Breathing frequency for an endurance athlete at maximal
60 breaths per minute
TV for endurance athlete at maximal
3L
VE for endurance athlete at maximal
180L/min
Describe the effect of exercise intensity on TV
- TV increases linearly with exercise intensity
- TV plateaus during submax intensity
Explain the effect of exercise intensity on TV
- TV increases with exercise intensity because O2 demand from muscles increases AND the respiratory system must get a greater volume of O2 into the lungs
- TV plateaus during submax intensity because increased f means there is not enough time during inspiration or expiration for any greater volume of air to be breathed in or out
Describe the effect of exercise intensity on breathing frequency
- F increases linearly with exercise intensity
- F plateaus as exercise intensity continues to rise towards maximal intensity
- F plateaus during sustained submaximal exercise
Explain the effect of exercise intensity on breathing frequency
- F increases with exercise intensity because O2 demand from muscles increases AND the respiratory system must get a greater volume of O2 into lungs
- F plateaus towards maximal exercise intensity because there is a minimum time for inspiration to ensure enough O2 enters the lungs
- F plateaus during sustained submax exercise because O2 demand = O2 supply + enough O2 is delivered to working muscles
Effect of submax exercise on VE
- Increase in VE before exercise = anticipatory rise due to adrenaline
- Fast increase in VE at start of exercise to cope with increased demand for O2 from muscles
- VE plateaus as body reaches steady state, as supply of O2 has caught up with demand from muscles
- Slower decrease in VE during 2nd stage of recovery to allow O2 consumption to stay above resting levels until lactic acid has been removed
Differences between the effects of submax and max intensity exercise on VE
- Max= no steady state reached- supply of O2 never catches up with demand from muscles
- Recovery time takes longer for VE to return to its pre-exercise value- higher intensity means there was more anaerobic work and more lactic acid to remove
