Question

Intestinal villi are numerous and larger in posterior part of small intestine than in anterior part because
A. Digestion is faster in the posterior part.
B. Blood supply is poor in posterior part
C. There is more digested food in the posterior part.
D. Blood supply is rich in the posterior part.

Answer 1

Intestinal villi are tiny finger-like projections present in the small intestine. The main function of the intestinal villi is to absorb the food that has been digested and allow this absorbed food to move into the bloodstream to provide the food to the body part that requires most of it.
Complete answer:
-Option (A) is incorrect. In the posterior part, maximum absorption of food takes place rather than the digestion process which takes place in the anterior part or duodenum of the small intestine.
-Options (B) and (D) are incorrect. Intestinal villi are finger-like projections that are lined by columnar epithelial cells, thus, helping in the absorption of food. So, their large number in the posterior part of the a smaller intestine than in the anterior part has nothing to do with the blood supply.
-Option (C) is correct. The main role of intestinal villi is to absorb the digested food and this maximum absorption takes place in the posterior part of the small intestine i.e., jejunum and ileum. Hence, the intestinal villi are present in large numbers in the posterior part of the small intestine because of the presence of more digested food in this part of the small intestine.
Hence, the correct option is (C).

Note:
The intestinal villi are lined by enterocytes or simple columnar epithelial cells. They are known for increasing the surface of the small intestine to provide maximum absorption of digested food. As more digested food is present in the posterior part of the small intestine, therefore, these villi are numerous and larger in the posterior part than in the anterior part of the small intestine.