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Remember that each system in a plant or an animal works to keep the plant or animal alive by performing life functions.

Our bodies work in really miraculous ways to perform life functions. In this activity, you will learn about one of the systems of the human body.

Digestive System

This system's role is to change the food you eat into simple chemical compounds that are able to enter the cells. Your body uses these compounds, which are called nutrients, for energy, growth, and repair. Nutrients include carbohydrates (sugars and starches), proteins, fats, vitamins, minerals, and water.

Above is a diagram of the digestive tract of a human being. Digestion begins when food enters the mouth and ends when food wastes leave the body through the anus.

Click here to read about specific parts of the digestive system:

1. oesophagus (esophagus): pushes food to the stomach through wave-like muscle contractions

2. stomach: muscles contract to mix food; stomach releases acids that activate enzymes to digest food; food is dissolved into liquid form

3. small intestine: neutralizes the stomach acid; absorbs 80 to 90 percent of nutrients; releases digestive juices to digest food

4. large intestine: absorbs vitamins, minerals, and water

Digging Deeper

Try This!

Click here to go to the Study Jams! website to watch a video that further explains the digestive system.

When you have finished watching the video, click on the "close" button in the upper right-hand corner to exit the video. Then, click on the "Test Yourself" button to see how much you know about the digestive system.

The Digestive System Works with the Circulatory System

The digestive system works with another body system, the circulatory system, like this:

1. Nutrients enter the blood stream from the digestive system through the capillaries.

2. The circulatory system carries digested food substances to the cells of the body.

3. The nutrients then travel around, over, and through each cell in the body.

4. Waste molecules pass from the cells back into the bloodstream through the capillaries.

5. The circulatory system helps to dispose of waste products and materials such as salts. (These materials would harm the body if they accumulated.)

You will learn more about the circulatory system in the next lesson.