Question

What are two structural features of the small intestine that add to its absorptive capacity?

Answer 1

The plicae circulares and villi & microvilli.

Explanation:

The major portion of digestion and absorption of ingested food occurs in the small intestine (approximately 80% of all major nutrient is absorbed here) . Small intestine (SI) is about 21 feet in length. So actually plenty of space.

But to increase its capacity of absorption the wall of SI is thrown into a series of folds. These folds actually increases the surface area. These are called PLICAE.

The innermost layer of the wall of SI, the mucosa contains 4 to 5 million microscopic finger like projections. These are VILLI. Each villi has in its core a capillary network to pick up absorbed nutrients.

In addition, each of the epithelial cells in the surface of the villi has a brush border of MICROVILLI. It further increases the capacity of absorption.

This is the diagram of plicae

And This is the diagram showing microscopic structure of a villus (plural Villi)