# Explain how the structure of the ileum is adapted to allow efficient absorption of the products of digestion into the blood.

> Pearson Edexcel International GCSE Biology (4BI1) — 2.6 Nutrition: humans · Explain · 4 marks

## Mark scheme (4 marks)

1. Villi increase the surface area (of the ileum / for absorption)
2. Larger surface area means more absorption (of digested food / products of digestion) can occur / absorption is faster
3. Good blood supply / network of capillaries (in each villus) maintains a steep concentration gradient
4. Walls of villi are only one cell thick so diffusion distance is short / substances diffuse quickly into the blood

## Key terms

- [ileum](https://www.gradenine.co.uk/glossary/ileum)

## Related

- [Revision notes for Pearson Edexcel International GCSE Biology (4BI1)](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

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Source: [GradeNine](https://www.gradenine.co.uk/q/explain-how-the-structure-of-the-e37d438d) · Published by Druglandscape Ltd.