Mention the role of following in digestion:

a. pepsin

b. saliva

c. villi

Pepsin is a protein digesting enzyme which remains inside the digestive juice secreted by the stomach. It digests and converts protein into peptones and proteoses.

In the digestion process, saliva helps the teeth and tongue to masticate and mix up the food thoroughly. Mucus in saliva helps in lubricating and adhering food particles into a bolus.  Then the bolus conveyed to pharynx for further digestion. Starch (carbohydrates) present in our food is broken down into simple sugars in the mouth by the enzyme, ptyalin or salivary amylase, present in saliva. Lysozyme present in saliva acts as an antibacterial agent that prevents infection.

The inner lining of the small intestine has millions of tiny finger-like projections called the villi. These projections increase the surface area of the small intestine for efficient food absorption.