Absorption of the products of digestion

Question 1

Where is the ileum and what is within the structure of the ileum?

Answer 1

The ileum is within the small intestine. Villi are situated at the interface between the lumen of the intestines and the blood.

Question 2

What are the adaptations of the ileum that increases the rate of absorption?

Answer 2

• walls are covered in villi which are covered in microvilli
• these villi and microvilli increase the surface area giving it more diffusion
• the villi are only one cell thick and therefore very thin walled, allowing diffusion to be quicker due to shorter distance
• large blood supply which maintains the concentration gradient of molecules