BRAINCAKEIncreasing the Rate of Diffusion
Tracheoles are the small tubes that form the terminal endings of the tracheal system and range from 1 to 0.1 μm in diameter.
Tracheole walls are capable of transporting oxygen at high rates by diffusion because they are thin (usually <0.1 μm) and have a very large surface area to volume ratio.
Thus, the tracheoles are the major site of gas exchange between the tissues and the tracheal system.
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Key terms in this lesson
- diffusion
- The net passive movement of molecules or ions from a region of higher concentration to a region of lower concentration, down a concentration gradient.
- osmosis
- The net movement of water molecules from a region of higher water potential to a region of lower water potential through a selectively permeable membrane.
- water potential
- The pressure created by water molecules, a measure of the tendency of water to move out of a solution; pure water has a water potential of zero and solutes make it more negative.
- surface area to volume ratio
- The ratio of an organism's or structure's external surface area to its total volume, which decreases as size increases.
More in Exchange of Gases
- Gas Exchange in Unicellular Organisms
- Gas Exchange in Insects
- Diffusion Gradient
- Mass Transport
- Limitations of the Tracheal System
- Gas Exchange in Fish
- Structure of the Gills
- Counter Current Exchange
All 28 lessons in Exchange of Gases · All AQA AS-level Biology topics