Ventilation = gas exchange college blok 2.3
VO2 max: maximum capacity of the body to take up oxygen. This is expressed in mL/min/kg. The VO2
declines when you grow older, and it’s lower in women than in men, because they have less muscle,
and more fat. With the lean body mass, you don’t take the fat in count, and then there is hardly any
gender difference.
Cross country skiing people (langlaufen) have the highest VO2. This is because:
- Its an ultimate endurance sport (the same like biking, etc.)
- They use as well their legs as their arms exclusive.
With an higher VO2 max, the anaerobic threshold is also higher: sport more with no/hardly any
lactate production.
Because you are excessively ventilating, although you produce CO2, your CO2 levels will go down.
Because of all the effects of high VO2 max you can exercise for a long time.
Whay determines our maximal aerobic exercise level?
-Respiratory muscles.
- Lungs.
- Pulmonary circulation.
- Heart.
- Oxygen transport by the blood.
- Systemic circulation.
- Muscle perfusion.
- Muscle metabolism.
- Muscle mass, innervation.
Myasthenia gravis interferes in the innervation of the muscles, and of the respiratory muscles. The
most important is the innervation of the muscles (so not respiratory ones).
De basis of all gas exchange is diffusion. The bigger the molecule, the slower it diffuses.
The partial pressure is the pressure that the gas would have if it alone occupied the volume of the
mixture at the same temperature.
The atmospheric pressure is 756 mmHg.
Nitrogen = 80% = 605 mmHg.
Oxygen = 20% = 151 mm Hg.
At other ambient pressures: partial pressures of nitrogen and oxygen scale proportionally.
The distance for the diffusion is the distance from the red blood cell in the pulmonary capillary and
alveoli. It is about 1 micrometer, and the area is about 75 m2.
This means that in a normal lung diffusion is not a limiting factor, only in severe lung conditions.
You can shorten the pulmonary capillary by 2/3th, and still have enough space for normal diffusion.
The lungs are not completely refreshed: you go from 151 mm Hg in outside air, to 104 in lungs.
Once you go from pulmonary vein to arterial blood, you loose a bit of your pO2 level. This is because
of the bronchial blood, which is a little bit less in oxygen, which is mixed with the oxygen rich blood.
Another part is that there is blood from the heart.
VO2 max: maximum capacity of the body to take up oxygen. This is expressed in mL/min/kg. The VO2
declines when you grow older, and it’s lower in women than in men, because they have less muscle,
and more fat. With the lean body mass, you don’t take the fat in count, and then there is hardly any
gender difference.
Cross country skiing people (langlaufen) have the highest VO2. This is because:
- Its an ultimate endurance sport (the same like biking, etc.)
- They use as well their legs as their arms exclusive.
With an higher VO2 max, the anaerobic threshold is also higher: sport more with no/hardly any
lactate production.
Because you are excessively ventilating, although you produce CO2, your CO2 levels will go down.
Because of all the effects of high VO2 max you can exercise for a long time.
Whay determines our maximal aerobic exercise level?
-Respiratory muscles.
- Lungs.
- Pulmonary circulation.
- Heart.
- Oxygen transport by the blood.
- Systemic circulation.
- Muscle perfusion.
- Muscle metabolism.
- Muscle mass, innervation.
Myasthenia gravis interferes in the innervation of the muscles, and of the respiratory muscles. The
most important is the innervation of the muscles (so not respiratory ones).
De basis of all gas exchange is diffusion. The bigger the molecule, the slower it diffuses.
The partial pressure is the pressure that the gas would have if it alone occupied the volume of the
mixture at the same temperature.
The atmospheric pressure is 756 mmHg.
Nitrogen = 80% = 605 mmHg.
Oxygen = 20% = 151 mm Hg.
At other ambient pressures: partial pressures of nitrogen and oxygen scale proportionally.
The distance for the diffusion is the distance from the red blood cell in the pulmonary capillary and
alveoli. It is about 1 micrometer, and the area is about 75 m2.
This means that in a normal lung diffusion is not a limiting factor, only in severe lung conditions.
You can shorten the pulmonary capillary by 2/3th, and still have enough space for normal diffusion.
The lungs are not completely refreshed: you go from 151 mm Hg in outside air, to 104 in lungs.
Once you go from pulmonary vein to arterial blood, you loose a bit of your pO2 level. This is because
of the bronchial blood, which is a little bit less in oxygen, which is mixed with the oxygen rich blood.
Another part is that there is blood from the heart.
