Alveolar Exchange CO2/O2 Exhange/Flow - Colombo Flashcards
What are the percentages of alveolar gases? (O, N, CO, H2O))
14% O2
75% N2
5% CO2
6% H2O
What 5 things affect rate of gas diffusion?
1-solubility of gas in the fluid
2-surface area of the barrier across which diffusion takes place
3-distance of diffusion
4-molecular weight of gas
5-temperature (though it is well regulated Inside the body)
What is tidal volume?
Normal volume of air displaced between inhalation and exhalation
What is functional residual capacity?
The amount of air still left after normal exhalation
What 2 things control the amount of oxygen in alveoli?
Ventilation from breathing
Rate of absorption into the blood (this is affected by many things)
When VA/Q approaches zero, what is happening? What does it result in?
Ventilation is poor or not as good as profusion.
Results in shunting
When VA/Q approaches infinity what is happening? What is the result of this?
Profusion is poor or not as good as ventilation.
Results in dead space
Where is dead space more prevalent?
In the superior region of the lung
Where is shunting more prevalent?
Inferior portion of the lungs
What is the equation for delivery of oxygen to the tissues?
DO2=CO x CaO2
Delivery of O2= cardiac output x arterial O2
What is the O2 partial pressure leaving the alveoli?
104 mm hg
What is the O2 partial pressure once shunted blood mixes?
95 mm hg
What is the O2 partial pressure in venous return?
40 mm hg
What is the equation for arterial oxygen content?
Arterial oxygen content= (1.34 x Hb concentration x O2 sat of Hb) + (0.003 x pressure of unbound O2)
What allows Hemoglobin to progressively increase its affinity for O2 as it binds?
Cooperative binding
