Gas Exchange

Question 1

State 2 functions of the respiratory system.

Answer 1

Pulmonary ventilation

Gas exchange

Question 2

State 2 types of gas exchange.

What are they?

Answer 2

External respiration: at the lungs (o2 into blood, co2 into lungs)
Internal respiration: at the muscles (o2 into respiring cells, removal of waste products)

Question 3

8 mechanics of breathing?

Answer 3

Larynx
Trachea
Bronchi
Bronchioles
Alveoli
Ribs
Diaphragm
Intercostal muscles

Question 4

How does the blood transport oxygen?

Answer 4

Bound to haemoglobin - 97% of o2

In plasma in the blood - 3% of o2

Question 5

What does oxygen and haemoglobin form?

Answer 5

Oxyhaemoglobin

Question 6

How is co2 transported in the blood?

Answer 6

In blood plasma - 8% of co2
Bound to haemoglobin in RBC’s - 20% of co2
In water (cytoplasm) as carbonic acid - 70% of co2

Question 7

What does co2 and haemoglobin form?

Answer 7

Carbaminohaemoglobin

Question 8

Why does co2 need to be removed?

Answer 8

To prevent fatigue

Question 9

What is breathing frequency, tidal volume and minute ventilation?

Answer 9

Breathing frequency (BF) - breathes per minute
Tidal volume (TV) - volume of air inspired or expired per breath
Minute ventilation (VE) - TV x BF

Question 10

2 functions of pulmonary diffusion?

Answer 10

Replenish blood with oxygen

Remove blood of co2

Question 11

What is partial pressure?

Answer 11

The pressure exerted by an individual gas in a mixture of gasses.

Question 12

How to gasses move?

What to what

Answer 12

High to low partial pressure.

Question 13

What unit is partial pressure measure in?

Answer 13

mmHg

Question 14

What is internal and external respiration?

Answer 14

Internal: gas exchange at the muscles
External: gas exchange at the lungs

Question 15

What is the atmospheric pressure of co2 and o2?

Answer 15

Co2: 0.23 (low)
O2: 159 (high)

Question 16

What is the pressure of o2 in the blood before and after the lungs?

Answer 16

Before: 40 (low)
After: 100 (high)

Question 17

Why is there a high partial pressure of o2 in the alveoli?

Answer 17

It contains atmospheric air where the pressure of o2 is 159.
Po2 in the capillaries is 40.
159>40

Question 18

What happens to external respiration during exercise?

Answer 18

The diffusion gradient of o2 steepens and therefore diffuses at a faster rate from a higher ppo2 in the alveoli to a lower ppo2 in the capillary blood.

The diffusion gradient of co2 steepens and therefore diffuses at a greater rate from a higher ppco2 in the capillary blood to a lower ppco2 in the alveoli.

Question 19

What happens to internal respiration during exercise?

Answer 19

The diffusion gradient of o2 steepens and therefore diffuses at a faster rate from higher ppo2 in the capillary blood to lower ppo2 in the respiring muscle cells.

The diffusion gradient of co2 steepens and therefore diffuses at a higher rate from higher ppco2 in the respiring muscle cells to lower ppco2 in the capillary blood.

Question 20

At rest, how much haemoglobin is saturated with o2; what does this mean?

Answer 20

75% saturated

25% of o2 is dissociated from the haemoglobin into the muscles.

Question 21

During exercise what % of haemoglobin is saturated with o2; what does this mean?

Answer 21

25% saturated with o2

75% of o2 is dissociated from the haemoglobin into the muscle cells for aerobic respiration.

Question 22

4 reasons that o2 dissociates more during exercise than at rest?

Answer 22

Decreased blood pH
Increased co2
Increased lactic acid
Increased temperature

Question 23

What is the Bohr shift on a graph?

Answer 23

The oxyhemoglobin dissociation curve shifts to the right as more oxygen is dissociated.