The Digestive System of the Human Body

Contributor: Nichole Brooker. Lesson ID: 11668

You eat yummy food you love, then later you poop, and get rid of that in a hurry! What happens in between? What happens to the food inside of you where you can't see it? It will be fun to find out!


Life Science

learning style
personality style
Grade Level
Primary (K-2)
Lesson Type
Quick Query

Lesson Plan - Get It!


Did you know that the acid in your stomach is strong enough to dissolve a steel beam, but does not affect plastic? The digestive system is amazing and, in this lesson, you will learn all about it!

The digestive system is responsible for breaking down your food and getting all the good stuff from it.

When you take a bite of food, your digestive system immediately goes to work. Your digestive system starts with the liquid in your mouth. That drool is actually called saliva. It starts to break down the food so it can become soft enough to go down your throat.


The tube that is in your throat is called the esophagus. This tube uses muscles to squeeze food down into the stomach. It takes seven seconds for food to go from your mouth to your stomach.

When your mashed-up food reaches your stomach, the acid in your stomach continues to break it down. The muscles in your stomach, along with the acid, work like a blender to mash up the food until it becomes a thick liquid. That liquid is then slowly pushed into the small intestines.

digestive system diagram

The small intestine looks like a coiled-up hose, but it isn't small at all! If you stretch out the small intestine of an adult, it would be about 22 feet long! Get a tape measure and see how long that is! You could also line 22 notebooks up end to end and that would be about 22 feet. Can you believe that all fits into a human body? The small intestine is a very important part of the digestive system because it breaks down the liquid that your stomach created from the food you ate so your body can absorb all the vitamins, minerals, fats, carbohydrates, and proteins.

There are other organs that are important to the digestive system: the pancreas, liver, and gallbladder. They work together with the stomach and intestines to further break down all the nutrients that are in your food to give your body the energy it needs.

gastrointestinal tract

Once all of those organs work together to separate out all the vitamins and nutrients, those good things go into your blood.

The leftover material that your body doesn't need is called waste. Your liver is the primary organ responsible for processing the nutrient-rich blood and filtering out the harmful stuff your body doesn't need. The liver will even keep some of the nutrients for later, and pass the rest of the waste to the large intestine or colon.

small and large intestines

This is where all of the waste comes together to make poop or feces! Yep, that's right, all living things need to get rid of the waste that the body cannot process. That means every person and every animal poops! It comes out the rectum and anus and you flush it away.

You sure have learned a lot about the digestive system! Check out this cool video on How the Digestive System Works, by Kids


WOW! Did you see all of the organs and parts of your body that have to work together to make the digestive system function? The human body is quite an amazing thing, and learning how it all works together is a great way to make sure you are taking good care of yours.

In the next section, you will take all of this information and create a flow chart to help you remember all the parts of the digestive system.

Get ready to fill out the Food to Flush Flowchart!

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