In this article, we will study five basic steps of Digestion in humans and The parts of the digestive tract Learn What is Digestion in 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 and the associated glands together constitute
the digestive system.
Understand the complete process of digestion in Humans with animated
learning videos. Get Online Class 7 Science notes of Digestion in humans.