Question

The function of villi in the intestine is
(A) Digestion of food
(B) To increase the absorption efficiency of the nutrients
(C) Control of intestinal movement
(D) Hindrance in the movement of food

Answer 1

Hint: Food is responsible for providing energy and organic materials for growth of every organism. The bio macromolecules which are present in food have to be broken down into smaller particles, so as to get absorbed efficiently. The digestive system of man contains many different organs, which help in digestion and absorption. Specifically, the small intestine is the region where maximum absorption takes place.

Complete answer:
The substances that are taken to supply the necessary nutrients to the body is termed as food. Large biomolecules present in the food are broken down into smaller particles in the digestive system. The method of conversion of complex food materials into simple absorbable forms is called digestion.

The human digestive system starts with the mouth or buccal cavity, which leads to oesophagus, stomach, small intestine, large intestine and ends with anus. The innermost layer lining the lumen of the digestive system or alimentary canal is called mucosa. Mucosa layer is found to be modified in each region of the alimentary canal. In the stomach, this layer forms irregular folds in order to aid in mechanical churning of food. In the small intestine, small finger-like foldings are called villi.

The cells lining the villi produce several microscopic projections called microvilli giving a brush border appearance. These modifications increase the surface area enormously. Increase in surface area of the small intestine, in turn increases the absorption efficiency of the nutrients.

Hence the correct answer is OPTION(B)

Note: An important point to remember is the significance and modification of the mucosa layer in different regions of the digestive system. Absorption of substances takes place in different parts of the alimentary canal like mouth, small intestine and large intestine. But, maximum absorption of smaller molecules takes place in the small intestine, because of villi.