D) System

Circulatory System

The Human System Lesson 3
The Human System Lesson 4

Respiratory System

The Human System Lesson 5

Digestive System

  • Breaks down food into simple substances

    • Absorbs these substances so that they can be used by the body

The food that we eat has to chewed and broken down into simple substances. This process is called digestion. The various organs in the digestive system carry out different functions.

Every organ in the digestive system has its own function. However, they must work together for digestion to take place smoothly. The digested food is then sent to different parts of the body by the circulatory system to provide the body with energy.

The Mouth

Digestion starts in the mouth. The food is chewed into smaller pieces. Saliva makes the food soft enough for you to swallow. The digestive juice in the saliva helps in the digestion process.

The Gullet

The food moves down a tube, known as the gullet, into your stomach.

The Stomach

Digestion of food continues inside your stomach. The food is digested further and mixed with other digestive juices.

The Small Intestine

More digestive juices are added to the food in the small intestine. Digestion of food is completed here. By now, the digested food can pass through the walls of the intestine into the blood. The blood then carries the digested food to different parts of your body.

The Large Intestine

The undigested food goes into the large intestine where water is removed from it. IT is then passed out of the body through an opening called the anus.

The Human System Lesson 6
The Human System Lesson 7

Comparison of Systems between Plants, Humans and Animals

The Human System Lesson 8