3.9 Absorption in the Small Intestine

Question 1

What are villi?

Answer 1

Finger-like projections, about 1mm long in the small intestine.

Question 2

What are the villi lined with?

Answer 2

Epithelial cells

Question 3

What 4 properties of the villi help absorption?

Answer 3

Increase surface for diffusion
Thin walled, reducing distance over which diffusion takes place
Able to move and help main diffusion gradient
Well supplied with blood vessels to help maintain diffusion gradient