Explain Digestion.

The human digestive system comprises a group of organs that digest and convert food into energy for the body.

The digestive system is made up of the gastrointestinal tract also known as an alimentary canal which includes the mouth, stomach, oesophagus, small intestine, and large intestine.

The accessory organs of the digestive system are the salivary glands, liver, pancreas, and gallbladder.

The food particles gradually get digested as they travel through various compartments of the alimentary canal. Accessory organs stimulate digestion by releasing certain enzymes that help in breaking down the food.

The five steps of digestion are as follows in the order of digestion of food:

1.Ingestion: It is the entry of food into the mouth. Chewing breaks the food into small pieces and saliva mixes with food that can be easily passed through to the stomach through the oesophagus.

2.Digestion: When food enters into the stomach the inner lining of the stomach secretes mucus, hydrochloric acid, and digestive juices. The acid makes the medium in the stomach acidic and helps the digestive juices which break down the proteins into simpler substances.

The small intestine receives secretions from the liver and the pancreas to breakdown the carbohydrates, fats, and proteins the digestion.

3.Absorption: The digested food passes into the blood vessels in the wall of the intestine which has thousands of finger-like outgrowths. These are called villi which increase the surface area for absorption of the digested food.

4.Assimilation: The absorbed substances are transported to different organs via the blood vessels. These substances are used to build complex substances like proteins. This is called assimilation.

5.Egestion: The undigested and unabsorbed food enters into the large intestine where water and some salts get absorbed from the undigested food material.

The remaining waste passes to the rectum. This faecal matter is removed through anus. This is called egestion.


Simply Easy Learning

Updated on: 10-Oct-2022


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