Properties Of Gases And Diffusion Flashcards
What is boyle’s law and what does it relate to in physiology?
Pressure of a gas is inversely proportional to its volume.
(If temperature and number of gas molecules remains constant in a closed system)
Inspiration and expiration
Why is atmospheric pressure lower at higher altitudes?
Because the air molecules are more dispersed.
What percentage of air is oxygen and nitrogen?
78% and 20.9%
How do you calculate amount of gas dissolved?
Amount dissolved = partial pressure x solubility coefficient of gas
How many mmHg is 101 kPa?
760mmHg
With respect to gaseous exchange what is the role of binding proteins such as Hb?
Keep pressure low allowing for a strong gradient for diffusion
Define partial pressure.
Pressure exerted by a dissolved gas in a liquid
Which is the pO2 of alveolar air lower than that of inhaled air?
Mixing with residual volume occurs and O2 leaves and diffuses across the alveolar wall.
What are the partial pressures of oxygen and carbon dioxide in venous blood?
Arterial blood? What is this the same as?
6 and 6
13 and 5.3
Same as alveolar partial pressures before gaseous change has occured.
Give 4 factors that affect the rate of diffusion?
Partial pressure gradient Surface area available for diffusion Diffusion distance Solubility Molecular weight
What 2 factors does solubility that into account?
Solubility and molecular weight
Why is arterial pCO2 normal compared to pO2 in pulmonary Edema?
CO2 a lot more soluble in water therefore sufficient diffusion occurs.
