Role and structure of villi

Question 1

Suggests three roles and structure of the villi/small intestine

Answer 1

Epithelial cells of villi contain many mitochondria to release more energy in the form of ATP during respiration for active transport in the absorption of nutrients
There are numerous transverse folds bearing thousands of tiny finger-like projections called villi to increase total surface area for absorption of nutrients
The small intestine is long and coiled, thus providing sufficient time and presents large absorbing total surface area to the digested nutrients.

Question 2

How does the villi affect the efficiency of absorption of foods

Answer 2

The epithelial lining is very thin so that digested nutrients can pass through it easily by shortening diffusion distance. The outer membrane of epithelial cell has a microvilli which greatly increases the surface area to volume ratio of one epithelial cell for the attachment of more brush border enzymes for digestion and carrier proteins for the absorption of nutrients