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

> Cambridge International IGCSE Biology (0610) — 7.5 Absorption · Describe · 4 marks

## Mark scheme (4 marks)

1. The ileum has a large internal surface area due to the presence of villi
2. Villi have a rich blood supply / dense network of capillaries to carry absorbed nutrients away quickly, maintaining a concentration gradient
3. The epithelial cells lining the villi have microvilli which further increase the surface area for absorption
4. Lacteals inside the villi absorb the products of fat digestion (fatty acids and glycerol) into the lymphatic system

## Key terms

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

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