Exchange in the gut

1. Exchange in the gut How is the gut adapted for digestion? Starter: What is the main goal of digestion? http://www.visit4ads.com/advert/Bounty-Kitchen-Rolls-Bounty-Kitchen-Paper/7552

2. Glossary • Villi – the finger like projections from the lining of the small intestine which increase the surface area for the absorption of digested food into the blood.

3. The Small Intestine The Small Intestine

4. Endoscopy • These projections called villi give the small intestine a surface area of about the size of a tennis court!

5. Villi • Villi provide a large surface area for diffusion to occur. They are 1 cell thick, have a rich blood supply that moves nutrients away quickly maintaining the concentration gradient and a moist surface so that nutrients can dissolve. • They increase the surface area by approximately 10 times. Active transport moves glucose out of the gut into the bloody quickly to make sure none of the digested food is wasted.

6. Task- answer these questions • Describe the main features of the small intestine that allow digestion to happen efficiently. • Describe the structure of a villus and relate this to its function. • Reflect on the structure of the alveoli and use this to make a comparison of alveoli and villi.

7. Task: Copy the diagram of the villi • Label the main features of a villus that allow it to do its job efficiently.

8. Lets investigate • What happens in the gut?

9. What takes place • Diffusion and active transport both occur to maintain the concentration gradient. • Active transport has to happen to make sure the nutrients are taken to the rest of the body and not wasted.

10. COMPETITION • Who can get the longest piece of string into a match box?!