| Diffusion of Gases across Alveolar-Capillary Membranes | ||
| The rate of diffusion of a gas across a membrane depends on following factors | ||
1 |
The pressure difference across the membrane of the gas in the mixture - the higher the pressure difference the higher is rate of diffusion of the gas. | |
2 |
The surface area of available for gas diffusion - the larger the area, the higher is the rate of diffusion. | |
3 |
The solubility of the gas in water - the higher the solubility, the faster is the rate of diffusion. | |
4 |
The thickness of the membrane - the larger the thickness, the slower is the rate of diffusion. | |
5 |
The size of the gas molecule - the larger the size, the slower is the rate of diffusion | |
In mathematical terms this can be written as :
Vgas = (P1 - P2) x A x D/T where:
| Vgas | = |
Rate of gas diffusion |
| (P1 - P2) | = |
Pressure difference across the membrane |
| A | = |
Surface Area of the membrane |
| D | = |
Solubility of the gas/square root of the molecular weight |
| T | = |
Thickness of the membrane |
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