Week One - Gas Laws Flashcards
What is inspiratory/expiratory reserve volume?
The extra volume that can be achieved over that at rest
What is partial pressure
A fraction of the total pressure exerted by each gas in a mixture,it is proportional to the percentage volume of that gas in the mixture.
Eg partial pressure of o2 = total pressure 101.1kPa X 20.9% (0.209) = 78.8kPa
What is Boyles law?
Pressure of gas is inversely proportional to the volume if temp and amount of gas is constant in a closed system
According to Boyles law, what happens at altitude?
There is less pressure the fore the molecules in the air are more spaced out.
On Everest, pO2 = 31.1kPa X 21% = 6.5kPa = 1/3 of sea level
What is Charles law?
Increasing the temperature increases the kinetic energy of molecules.
If the volume and amount of gas is constant then pressure is directly proportional to temperature.
What is vapour pressure?
The pressure entered by the Water molecules evaporating and entering the gas phase. They will reach an equilibrium.
What is the saturated vapour pressure?
The pressure the gas exerts when saturated with vapour.
Depends one temperature. SVP = 6.28kPa at 37^
What is the effect of SVP on pO2 and pN2 in the air we breathe?
The air we breathe in is saturated with vapour as it passes through the nose. We therefore have to include ph2o in our equation.
101kpa = ph20 + po2 + pn2
101- 6.28 = po2 + pn2
Eg 94.72 X 0.209 = 19.7kpa
Gases will also dissolve in the liquid until an equilibrium is reached, referred to as gas tension or partial pressure of gas in liquid. What is the tension exerted by a gas in the liquid at equilibrium?
It will equal the partial pressure of the gas in the gas mixture
What is the solubility coefficient of oxygen?
0.1 mmol/L/kPa at 37^
Total oxygen content considers both the content oxygen content of…
The plasma and the haemoglobin = 8.93mmol.l-1
At what level of branching are the terminal bronchioles?
17
Roughly how many terminal bronchioles are there?
200000
After terminal bronchioles what happens?
It is the end of the conducting pathway and becomes the respiratory pathway. They divide into respiratory bronchioles then alveolar ducts and then alveolar leaves
Give three facts about the pulmonary circulation
Low resistance
Low pressure
Receives entire cardiac output
