3.2. Respiratory System 2

Question 1

Association

Answer 1

When O2 combines with haemoglobin through diffusion at the lungs to give oxyhaemoglobin

Question 2

Dissociation

Answer 2

When O2 releases from haemoglobin through diffusion at the muscles

Question 3

Oxyhaemoglobin dissociation curve

Answer 3

Shows us the relationship between PPO2 and % saturation of haemoglobin

Question 4

Oxyhaemoglobin dissociation curve at rest

Answer 4

• 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

Question 5

What happens to the curve as intensity increases?

Answer 5

Shifts to right

Question 6

Why does the curve shift to the right- oxygen?

Answer 6

• 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

Question 7

Why does the curve shift to the right- Co2?

Answer 7

• 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

Question 8

Why does the curve shift to the right- body temp?

Answer 8

Body temp increases which makes O2 dissociate from haemoglobin more readily

Question 9

Why does the curve shift to the right- acidity?

Answer 9

• 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

Question 10

Average breathing frequency at rest

Answer 10

12 breath per min

Question 11

Average TV at rest

Answer 11

0.5L

Question 12

Average VE at rest

Answer 12

6L/min

Question 13

Breathing frequency for an endurance athlete at rest

Answer 13

10 breaths per min

Question 14

TV for an endurance athlete at rest

Answer 14

0.5L/min

Question 15

VE for endurance athlete at rest

Answer 15

5L/min

Question 16

Average breathing frequency at maximal

Answer 16

50 breaths per min

Question 17

Average TV at maximal

Answer 17

2.5L

Question 18

Average VE at maximal

Answer 18

125L/min

Question 19

Breathing frequency for an endurance athlete at maximal

Answer 19

60 breaths per minute

Question 20

TV for endurance athlete at maximal

Answer 20

3L

Question 21

VE for endurance athlete at maximal

Answer 21

180L/min

Question 22

Describe the effect of exercise intensity on TV

Answer 22

• TV increases linearly with exercise intensity
• TV plateaus during submax intensity

Question 23

Explain the effect of exercise intensity on TV

Answer 23

• 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

Question 24

Describe the effect of exercise intensity on breathing frequency

Answer 24

• F increases linearly with exercise intensity
• F plateaus as exercise intensity continues to rise towards maximal intensity
• F plateaus during sustained submaximal exercise

Question 25

Explain the effect of exercise intensity on breathing frequency

Answer 25

- 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

Question 26

Effect of submax exercise on VE

Answer 26

- 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

Question 27

Differences between the effects of submax and max intensity exercise on VE

Answer 27

- 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