Villi
Contents
Key Stage 3
Meaning
Villi are small folds in the wall of the small intestine that increase its surface area.
Adaptations of Villi
- Villi have a wall only one cell thick so the nutrients only have a short distance to diffuse into the blood.
- Villi have capillaries inside them for a good blood supply to allow for quick diffusion into the blood.
- Villi have a large surface area to allow quicker diffusion.
- The cells in the walls of the villi have microvilli to provide an even bigger surface area for quicker diffusion.
About Villi
- Villi cover inside of the small intestine.
- Villi increase the surface area of the small intestine.
 |
Key Stage 4
Meaning
Villi are small folds in the wall of the small intestine that increase its surface area.
Adaptations of Villi
- Villi have a wall only one cell thick so the nutrients only have a short distance to diffuse into the blood.
- Villi have capillaries in order to constantly supply enough fresh blood with few nutrients keeping a high concentration gradient between the food and the blood.
- Villi have a large surface area to allow quicker diffusion.
- The cells in the walls of the villi have microvilli to provide an even bigger surface area for quicker diffusion.
About Villi
- Villi cover inside of the small intestine.
- Villi increase the surface area of the small intestine.
|
References
AQA
- Villi, page 21, GCSE Combined Science; The Revision Guide, CGP, AQA
- Villi, page 24, GCSE Biology; The Revision Guide, CGP, AQA
- Villi, page 45, GCSE Combined Science Trilogy 1, Hodder, AQA
- Villi, page 59, GCSE Combined Science Trilogy; Biology, CGP, AQA
- Villi, page 65, GCSE Biology, CGP, AQA
- Villi, pages 15, 23, 39, GCSE Biology; Third Edition, Oxford University Press, AQA