Question

Where does the process of food digestion start in human beings?
A. Stomach
B. Food canal
C. Mouth
D. Intestine

Answer 1

The breakdown of large insoluble food molecules into small water-soluble food molecules is known as digestion. It takes place so that they can be absorbed into the blood plasma. These smaller substances are absorbed through the small intestine into the bloodstream in certain organisms. Digestion can also be referred to as a form of catabolism which is often divided into two processes based upon how food is broken down: mechanical and chemical digestion.

Complete answer:
Option A) Stomach: It is a muscular organ which is located on the left side of the upper abdomen. From the esophagus, the stomach receives food. Several digestive juices and enzymes are made inside the stomach that mixes with food. These enzymes break down the food received. Although digestion takes place in the stomach, digestion does not start with the stomach.
Hence option A is not correct.
Option B) Food canal: The food pipe or food canal, also known as oesophagus is part of the digestive system. The food pipe is the tube which carries food from the mouth into the stomach. The food pipe lies behind the windpipe and at the front of the spine. Digestion does not start from the food canal.
Hence option B is not correct.
Option C) Mouth: The process of digestion starts in the mouth when food is chewed. The salivary glands make saliva, which is a digestive juice and it moistens food so that it can move more easily through the esophagus into the stomach. Saliva also has an enzyme which helps in breaking down starch present in the food.
Hence option C is the correct answer.
Option D) Small intestine: It is an organ present in the gastrointestinal tract where most of the absorption of nutrients and minerals from the ingested food takes place. Although digestion takes place in the small intestine, digestion does not start with the small intestine.
Hence option D is not correct.

Hence, Option C) Mouth is the correct answer.

Note:
The mechanical and chemical digestion starts from the mouth with chewing of food and releasing of saliva, which further starts digestion of carbohydrate. The tongue positions the bolus or the ball of chewed food for swallowing and then peristalsis pushes this down the esophagus into the stomach. Inside the stomach, acids and enzymes are secreted which breaks down food into its nutrient components.