Question

State the role of the following in human digestive system 1. Digestive enzyme 2. Hydrochliric acid 3. Villi

Answer 1

Digestive enzymes have one main job — to digest our food. DIGESTIVE ENZYMES are made by our body's organs. Digestive enzymes are secreted by the salivary glands, stomach, pancreas, and the small intestine. [Technically, digestive enzymes are also considered to be metabolic enzymes whose metabolic role is to digest food.

HCl also has another important role to play in the stomach during thedigestion process. The presence ofHCl in the body of the stomach causes the activation of enzymes. One of the proteins in HCl is used to convert the enzyme pepsinogen into pepsin. Pepsin breaks up the peptides from the protein.

 villi and the microvilli increase intestinal absorptive surface area approximately 30-fold and 600-fold, respectively, providing exceptionally efficient absorption of nutrients in the lumen. There are also enzymes (enterocyte digestive enzyme) on the surface for digestion.

Answer 2

Answer:

(i) Digestive enzymes – Foods need to be broken into their small or simpler

molecules so that they can be absorbed into the bloodstream. However, the physical breakdown of food is not enough. Enzymes are hence needed for the chemical breakdown of food and speeding up the digestive process. The products of digestion can hence be small enough to be absorbed.

(ii) Hydrochloric acid – Hydro chloric acid helps to kill the germs which might have entered in to the system through food. It creates acidic medium for the pepsin to act on food to breakdown proteins.

(iii) Villi – Villi are finger like projections in the small intestine. They help to increase the surface area for absorption of the digested food. Villi are richly supplied with blood vessel which help to absorb digested food in to the blood stream.

Explanation: