Lesson 8 of 9
Absorbing food
Goal: Explain how the small intestine is adapted to absorb food.
The wall of the small intestine is covered with millions of tiny villi. They give it a very large surface area, so food is absorbed quickly.
Two villi, one of them cut open. Each villus is about 1 mm long.
- A bigger surface area means faster absorption. More food molecules can pass through the wall at the same time.
- The wall of a villus is thin. It is only one cell thick, so the molecules have a short way to go.
- Each villus has a good blood supply. Blood in its capillaries carries the food molecules away to the rest of the body.
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Key words in this lesson
Small intestine Where digestion is completed and food is absorbed into the blood
Villi Tiny finger-shaped bumps that line the small intestine