The importance of exchange surfaces and transport systems in humans
I can explain how exchange surfaces and transport systems enable cells in multicellular organisms to be quickly supplied with substances they need to stay alive.
The importance of exchange surfaces and transport systems in humans
I can explain how exchange surfaces and transport systems enable cells in multicellular organisms to be quickly supplied with substances they need to stay alive.
Lesson details
Key learning points
- Consequences for living organisms of relationship between surface area:volume ratio and diffusion time.
- Reasons why a small surface area (relative to volume) could be a disadvantage to living organisms.
- The circulatory system minimises diffusion distance for oxygen and food molecules so cells can be supplied quickly.
- Examples of exchange surfaces in humans (e.g. alveoli in lungs, villi in digestive system).
- The exchange surfaces are adapted to maximise surface area for diffusion of particles of essential substances and waste.
Keywords
Surface area - The total area of the surface of an object.
Surface area to volume ratio - The relationship between the surface area and the volume of a shape.
Diffusion - The net movement of particles from an area of higher concentration to an area of lower concentration.
Exchange surfaces - A specialised surface which enables the efficient exchange of substances.
Common misconception
Pupils may think that villi and alveoli increase surface area without changing volume.
These ideas are explored in detail with examples and demonstrations using cube animals. The issue of surface area to volume ratio and diffusion rate is covered thoroughly, along with solutions to the issues in humans.
Licence
This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).
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