Question

Which part of the digestive canal is involved in

(i) absorption of food

(ii) chewing of food

(iii) killing of bacteria

(iv) complete digestion of food

(v) formation of feces

Answer 1

Digestive canal:

1. The digestive canal is a long hollow tubular structure that contains various organs for digestion.
2. The process by which your body breaks down food into smaller nutrient molecules is called digestion.
3. Both physical and chemical changes occur in the digestion of food.

(i) Absorption of food:

1. The small intestine is the longest part of the alimentary canal.
2. In an adult male, it is about 6.5 m long.
3. It is very long, it is called the small intestine because it is very narrow.
4. On the inner wall of the small intestine are found numerous finger-like projections called microvilli, which are involved in the absorption of food digestion to increase the surface area.

(ii) Chewing of food:

1. The alimentary canal is a long tube through which food passes.
2. It begins in the oral cavity and continues through the pharynx, esophagus or food pipe, stomach, small intestines, large intestines, rectum, and other parts of the digestive tract until it reaches the anus.

(iii) Killing of bacteria:

1. Bacteria are killed in the stomach. It acts as a muscle bag located on the left side of the abdominal cavity, below the diaphragm.
2. This vital organ serves as the storage of food and provides enough time for the food to be digested.
3. Digestive enzymes and hydrochloric acid are also produced in the stomach, which aid digestion and destroy microorganisms.

(iv) Complete digestion of food:

1. Complete digestion of food occurs in the small intestine.
2. From the liver, pancreas, and the walls of the small intestine, the duodenum ingests partially digested food.
3. Bile juice is secreted by the liver, which breaks down fats into small droplets, making them easier to digest.
4. The pancreas produces pancreatic juice that breaks down fat into fatty acids and glycerol.
5. The small intestine's walls secrete digestive juice, which breaks down starches and carbs into simple sugars. Glucose is the name for these sugars. Proteins are also converted into amino acids.
6. All these simply broken down forms of food are called digested food.

(v) Formation of faeces:

1. The formation of feces takes place in the large intestine.
2. It is a thick, long tube about 5 feet in length.
3. It is present just below the stomach and wraps around the upper and lateral sides of the small intestine.
4. The bacteria, called symbionts, in this bacterium, absorb water and break down waste into smaller nutrients.