Gas Laws Flashcards
Explain Boyle’s law.
The pressure of a gas is inversely proportional to its volume.
What is meant by partial pressures of a gas in a gas mixture?
Each gas in the mixture exerts a partial pressure equal to the pressure it would exert if it was the only gas present.
What is meant by partial pressure of a gas in liquid?
The amount of a gas dissolved is proportional to the pressure of the gas in contact with the liquid.
Explain the movement of air when you exspire.
When the chest collapses the volume of air in the lungs decrease, hence the pressure increases so the partial pressure of atmospheric oxygen is slightly lesser than that of the partial pressure of oxygen in the lungs. Oxygen therefore moves down its pressure gradient out of the lungs.
Give 4 reasons why alveoli are adapted well for gas exchange.
- Short gas exchange pathway
- Rich blood supply to maintain a concentration gradient
- Moist membrane
- Large surface area of volume ratio
What is the value of saturated vapour pressure at body temperature?
6.28kPa
What is the value of saturated vapour pressure at body temperature?
6.28kPa
Quote the partial pressure values of oxygen and carbon dioxide in the venous circulation.
Oxygen: 6.0
Carbon Dioxide: 6.0
Quote the partial pressure values of oxygen and carbon dioxide in the arterial circulation.
Oxygen: 13.0
Carbon Dioxide: 5.3
Explain why the partial pressure of gases in alveolar air are different to that of atmospheric air.
It has added water vapour (at a value of 6.28 kPa) and as oxygen is constantly leaving and carbon dioxide constantly entering the alveolar air due to gas exchange, the oxygen percentage is lower and the carbon dioxide percentage is higher.
Explain how being at higher altitudes affects the amount of oxygen present in the blood.
There is a lower partial pressure of oxygen at higher altitudes hence there is less of a concentration gradient. This means less oxygen moves into the lungs, hence less is available for the tissues.
Explain decompression sickness in divers.
During deep diving, nitrogen moves from high pressure in the lungs into the blood (low pressure). A slow return to the surface lets the nitrogen return to the lungs where it is breathed out, however, swimming up too quickly don’t give the nitrogen enough time to leave the blood- instead it forms painful bubbles.
