1.What is the influence of humidified air , on partial pressure of gases ?
Air equilibrate with water is saturated with water vapor. The air reaching the lungs is saturated by humidification procedures in the airways . By the additional water vapour component , the percentage of the individual gases are lowered and therefore the partial pressure of them . As the total pressure is the sum of all the partial pressures . The partial pressure of water vapour is 47 mmHg at body temperature , which results in the reduction of PO2 to 149 mmHg which is 160 mmHg in the absence of water vapour
2.Write down the partial pressures of O2 and CO2 in alveolar air , arterial blood and mixed venous blood.
|
O2 mmHg
|
CO2 mmHg
|
Alveolar air
|
100
|
40
|
Arterial blood
|
95
|
40
|
Mixed venous blood
|
40
|
46
|
3. Define diffusing capacity of the lung
Definitions of diffusing capacity
Diffusing Capacity (DL) = Rate of gas transfer / Difference in the pressure gradient of arterial and venous blood
Hence , diffusing capacity is the rate of gas transfer across a membrane , in this case the alveolar capillary membrane , per unit change pressure gradient.Labels: Revision, RS, RS SEQs