Digestive System

This concept is about the human digestive system. This will explain about different digestive system organs in detail. Students will also get an idea about the structure of digestive system.

After reading the concept, students will be able to:

Explain human digestive system with their anatomical features.
Understand about the
- Parts of small intestine.
- Parts of large intestine.
- Oral cavity anatomy.
- Anus function in digestive system.
Draw a labelled diagram of human digestive system.

Each concept is explained to class 4 students using descriptions, illustrations, and concept maps. After you go through a concept, assess your learning by solving the two printable worksheets given at the end of the page.

Download the worksheets and check your answers with the worksheet solutions for the concept of Human Digestive System provided in PDF format.

What is the Digestive System?

The different organs and body parts of the human body that are involved in the process of digestion constitute the digestive system.

The human digestive system includes the gastrointestinal tract and the other accessory organs of digestion.

Digestive System Organs:

Mouth/Oral cavity: The first part of the digestive system is the oral cavity, which has the tongue, teeth and salivary glands inside it. Food enters the body through the mouth.

Salivary Glands: These glands are present inside the oral cavity. They secrete a fluid-like substance called saliva.

Oesophagus: Next comes the oesophagus or the food pipe, a tube-like structure that extends up to the stomach. Food passes from the mouth to the stomach through this tube.

Liver: The liver is located at the right side of the body below the ribs, above the stomach. It secretes bile. The liver is the largest organ of the human body.

Stomach: The stomach is a hollow organ located on the upper left side of the belly. It collects food from the oesophagus and passes it to the intestines.

Gall Bladder: It is a pear-shaped gland attached to the liver with a tube. It lies just beneath the liver and stores bile secreted by the liver.

Pancreas: It is a flat gland that is located behind the stomach. It secretes juices that help in digestion of food.

Small Intestine: It remains coiled but is the longest region of the digestive system. The liver and the pancreas remain joined to the small intestine with tubes. The food remains stored in the small intestine for some time.

Large Intestine/Colon: In comparison to the small intestine, the large intestine is shorter and broader. The undigested food materials pass through this part as waste.

Anus: The last part of the digestive system is the anus. It is an opening through which solid undigested food materials are excreted out of the body as faeces.

Digestive Glands:

There are five types of glands present in the digestive system—

Salivary glands, liver, gall bladder, pancreas and gastric glands of the stomach.
They secrete juices that facilitate the process of digestion.

New words

Glands : These are tissues or organs that produce substances required by other tissues or organs to work properly. Glands can be of two types—exocrine and endocrine.

Bile : A fluid made and secreted by the liver and stored in the gall bladder. Bile aids in digestion and helps in the breakdown of food.

Did You Know?

When a baby grows inside the womb, her liver produces blood that carries oxygen to all parts of the body.The small intestine, as the name suggests, isn’t small at all. If the coiled structure is stretched out, it will cover space of the size of an entire tennis court.

You must have heard your stomach make sounds. But do you know why it does so? It sounds the loudest when your stomach is empty. It happens due to the movement of fluids and gases in your stomach. The sound is described as ‘borborygmi’.