Digestive System

Digestive System Function for Class 4 Science

Digestive system plays an important role in our body. Carbohydrates proteins and fats are the main components of food that get digested with the help of digestive juices released by digestive system organs. In this concept, students will be introduced to digestive system functions.

After reading the concept, students will be able to:

• Know the human digestive system parts and functions like:
  • Liver function in digestive system.
  • Function of gallbladder in digestive system.
  • Pancreas function in digestive system.
  • Stomach function in digestive system.
• Understand emulsification of fats, carbohydrate digestion, lipid digestion, and protein digestion
• Explain how undigested food in stool is expelled outside anus,
• Know that liver is the largest gland in human body and it plays important role in emulsification of fats.
• Get an idea about absorption of digested food in the body.

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 Digestive System Function provided in PDF format.

The digestive system of the human body consists of many organs and glands. Each of them has a specific set of functions that aid in the process of digestion.

Digestionis how the food we eat is broken down into simpler forms inside our bodies.The different organs and glands of the digestive system and their roles are described below.

Organs and Glands	Functions
	Oral Cavity: It is the first part of the digestive system. It consists of the tongue, teeth and salivary glands. The teeth help to grind and chew the food we eat. The tongue helps in the movement of food during chewing and helps in swallowing.
	Salivary Glands: There are three pairs of salivary glands in our mouth. The salivary gland secretes saliva that helps to moisten food and allow the food to be swallowed easily. A particular substance present in the saliva help in the initial process of digestion of starchy foods.
	Oesophagus/Food Pipe: After we chew our food properly, it enters the oesophagus. It is a long hollow tube through which food is carried forward to the stomach.
	Stomach: It is a hollow pouch-like organ. The food is stored in the stomach for several hours. The gastric glands of the stomach release digestive juices that mix with the food. Partial digestion of food takes place in the stomach.
	Liver: It is the largest organ of the digestive system. It secretes a yellowish-green fluid called bile. Bile is essential for the digestion of fatty food.
	Gall Bladder: It is a pear-shaped gland that is connected to the liver. The gall bladder helps the liver by storing the bile produced when digestion of food is not taking place. When the fatty food reaches the duodenum (the first part of the small intestine), the gall bladder squeezes to push out bile that helps in digestion.
	Small Intestine: It exists as a coiled structure, and here, the nutrients and minerals from the digested food are absorbed into the body. The major part of food gets digested in the small intestine. It has many blood vessels that help in the absorption of nutrients and minerals.
	Pancreas: It secretes juices that help in the digestion of all food components. When food enters the small intestine, the pancreas gets a signal to secrete the juices that travel to the small intestine via tubes thereby aiding digestion.
	Large Intestine: It is the part that comes after the small intestine. Water and salts from the undigested food get absorbed in the large intestine. It also stores the solid undigested food as faecal matter till it is expelled out of the body.
	Anus: It is the last part of the digestive system. The anus is an opening in the body that helps to expel out the solid undigested waste matter from the body.

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Did You Know?

• Apart from being a vital organ of the digestive system, the liver also helps purify the blood.
• Animals like cows, deer, and giraffes have stomachs with four chambers to digest the plant-based foods they eat.
• The entire process of digestion takes 2-6 hours to complete.