Specialised exchange surfaces
- Created by: emily.tx
- Created on: 10-05-17 12:10
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- The need for specialised exchange surfaces
- Multicellular Organisms
- Increased SA provides area needed for exchange and overrides limitations of SA:V ratio in larger organisms
- Thin layers mean distances are shorter for diffusion so the process is efficient
- e.g alveoli in lungs
- Good blood supply ensures substances are constantly delivered and removed from the exchange surface to maintain steep conc. gradient for diffusion
- A ventilation system for gases helps maintain conc. gradient and makes process more efficient
- Single celled organisms
- Metabolic activity is low so oxygen demands and carbon dioxide production is relatively low
- (Diffusion alone is enough)
- SA:V ratio is large
- Multicellular Organisms
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