Question

How is the structure of a villi in the small intestine related to its function?

Answer 1

Small intestine:

1. The small intestine is the alimentary canal's longest segment.
2. It has a large internal surface area despite being a very narrow tube.
3. In humans, it is the site of complete digestion.
4. It completely absorbs digested food.
5. It secretes digestive juice.
6. It is supplied with bile from the liver and pancreatic juice from the pancreas.

Villi:

1. Villi are small intestine vascular projections that project into the intestinal cavity.
2. Each villus has numerous microvilli protruding from its epithelial surface.
3. Villi are specialized for absorption and have extremely thin walls that are only one cell thick.
4. They have a plentiful blood supply to maintain a concentration gradient.
5. The intestine's villi move in swaying, contracting motions.
6. These movements improve absorption by increasing the flow of blood and lymph.
7. Digestive enzymes are present on the surface of the villi to aid digestion.
8. Villus capillaries collect amino acids and simple sugars absorbed by the villi and transported into the bloodstream.
9. The villi's specific and elaborate structure aids in increasing the membrane's surface area.
10. The villi of the small intestine, significantly increase the surface area for food absorption and add digestive secretions.
11. Increased absorptive area is beneficial because digested nutrients absorb nutrients from the lumen exceptionally and efficiently.