Question

In the human alimentary canal, name the site of the complete digestion of various components of food.

Answer 1

Hint: Human alimentary canal begins with the mouth where food is ingested, oesophagus, stomach, small intestine, large intestine, rectum and ends at anus through which the undigested food is eliminated from the body. The digestion of the specific components of the food takes place in the various parts of the alimentary canal.

Complete answer:
Digestion is the breakdown of the various components of food into simpler substances that can be easily absorbed by our body.
Let us discuss the digestion of food at various parts of the alimentary canal.

1. Mouth- The mouth is the first part of the alimentary canal where the starch is broken down into simple carbohydrates with the help of the enzyme salivary amylase.
2. Stomach- It is the important centre of the digestion of proteins. The proteins are broken down into peptides by the enzyme pepsin in the presence of hydrochloric acid.
3. Small intestine- It is the most important part of the alimentary canal where the complete digestion of all the nutrients takes place. It receives bile from the liver which helps in the emulsification of fat. Further, it also receives gastric juices from other accessory organs like the pancreas which break down the proteins and carbohydrates.
4. Large intestine- It is the area where reabsorption of the nutrients takes place.
5. Rectum- It is the storehouse of undigested food.
6. Anus- The undigested food is eliminated from the body through the anus.

Thus, the site of the complete digestion of various components of food takes place in the small intestine.

Note: The small intestine is very long that is around 1.5 meters. Its walls have microvilli for better absorption of the nutrients. The pancreatic juices contain trypsinogen, carboxypeptidases, nucleases, amylase, pancreatic lipase, chymotrypsinogen etc in the inactivated form. They are activated once it reaches the small intestine.