Question

What are Villi? Mention their functions.

Answer 1

Hint: Several blood vessels are found within these villi, which absorb the digested food and transfer it to the bloodstream. The ingested food is thereby distributed with each and every cell in the body from the bloodstream.

Complete Answer:
There are millions of tiny finger-like projections known as villi in the small intestine. For more effective food absorption, these villas improve the surface area.
- Villi raises the inner surface area of the intestinal walls, allowing a wider absorption surface area accessible.
- An improved absorption region is advantageous since digested nutrients migrate by diffusion via the semi permeable villi, which is only efficient at short distances.
- For digestion, there are enzymes on the surface. Amino acids and basic sugars picked up by the villi are collected by Villi capillaries into the blood supply.
- Villi lacteals (lymph capillaries) accumulate ingested chylomicrons consisting of triglycerides, amphipathic proteins and cholesterol, that are lipoproteins and taken via the lymph fluid to the remainder of the body.

Note: As they have a thin wall, one cell wide, which makes a shorter diffusion path, Villi are specialised for absorption in the small intestine. They have a wide surface area, so the absorption of fatty acids and glycerol into the bloodstream would be more effective. To sustain a concentration gradient, they provide a rich blood supply.