1. The movement of digested food through the walls of the small intestine into the blood capillaries is called absorption.

 

2. Absorption takes place because of diffusion.

 

3. Adaptations of the small intestine for absorption:

(a) The internal surface of the lower part of the small intestine is covered by finger-like projections called villi. The villi increase the surface in contact with digested food. Food can be absorbed at a faster rate.

 

(b) The small intestine is about 7 m long. This ensured that most of the digested food has been absorbed before reaching the large intestine.

 

(c) The walls of the small intestines are richly supplied with blood vessels to carry away the digested food.

 

4. Digested food is carried in the blood from the small intestine to the liver. From the liver, the digested food is tranported to the heart and then to all parts of the body.