What is Digestion Class 7 Science

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What is digestion? Class 7 Science Digestion in humans : Human beings exhibit a holozoic mode of nutrition involving five basic steps i.e., ingestion, digestion, absorption, assimilation, and egestion.

Digestion: The process by which food is broken down into simple absorbable substances is called Digestion. Digestion of food takes place in the digestive system. The digestive system is composed of the alimentary canal and associated glands. Digestion in man is an extracellular process. Humans take food through the mouth, digest the food and finally, the undigested food is removed from the body. The food passes from the oral cavity and finally, the undigested food is defecated through the anus.

It is a complex process involving the following steps: 

Ingestion – Ingestion refers to the intake of food. Ingestion takes place through Mouth

Digestion – Digestion refers to the breakdown of ingested food into simpler forms. Teeth, Stomach, Small intestine and secretion from various glands help in Digestion

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Absorption – Absorption refers to the process in which digested food is absorbed into the body fluids (Blood & lymph). Small intestine plays a major role in Absorption

Assimilation – Assimilation refers to the process in which absorbed food is transported to different cells of the body

Egestion – Egestion refers to the process of removal of undigested food from the body. Large intestine plays a major role in Egestion

Parts of the digestive tract in humans The digestive tract in humans starts from the mouth and ends at the anus. It is also called as the alimentary canal.

The parts of the digestive tract are: 

Mouth and buccal cavity

Food pipe/Oesophagus

Stomach

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Small intestine

Large intestine

Rectum

Anus

There are some associated glands that secrete enzymes which help in digestion of food. These include: 

Salivary glands

Liver

Pancreas

The digestive tract the digestive system.

and

the

associated

glands

together

constitute

Understand the complete process of digestion in Humans with animated learning videos. Get Online Class 7 Science notes of Digestion in humans.

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