There’s a saying, "You are what you eat."

Did you know that is literally true?!

We need vitamins, and minerals to grow and repair ourselves.

Our bodies also need energy to work.

We eat food to get vitamins, minerals, fats, and proteins to build our bodies, and to get the energy we need to keep our bodies running.

This system in our body is called the Digestive system, or the Alimentary Canal.

The mouth is the beginning of the digestive system and breathing system. The lips, teeth, saliva, tongue, palate, and muscles help chew the food.

The teeth rip and grind the food that is too big or too tough to swallow. The saliva is added to soften and mix the food.

The jaw also helps us chew our food. Our taste buds help us to taste our food. Some books say that your taste buds are only on some places on your tongue, but that’s not true.

Yes, we can put food anywhere on our tongue and taste sour, sweet, bitter, and salty.

Your mouth has to finish this process and after you are done chewing, you swallow the wad into the throat.

After your food is chewed it goes down your throat through a long tube called the esophagus, and ends up in your stomach.

The esophagus is 10 inches short.

The esophogus carries food down to the stomach,

It runs down through the chest and passes behind your heart.

When you get heartburn it doesn’t have to do with the heart. Your esophagus starts hurting because stomach acids is coming up the esophagus, but it’s not suppose to do this.

Sometimes the food goes down the wrong way into the trachea.

Usually the epiglottis acts like a little door to keep food out of the windpipe and lungs, but sometimes an accident happens.

This is called choking.

If all goes well, food goes down the esophagus and is pushed down by a wave called peristalsis

Hi, My name is Stomach and I want to tell you about my job. I work in an assembly line, actually a disassembly line. You’ll see what I mean.

The disassembly line starts with the food going down the mouth through the esophagus, and into my talented hands-er’, my talented control.

My job is to break the food up. To do this I mix it up with some super powerful elements I possess: hydrochloric acid, enzymes, and pepsin.

I have a specialized glove to protect my wall from those elements. It is called the mucus lining. Sounds gross, Huh?

When I get the food, it is very chunky. After about an hour of my turning and churning it, the food is more like oatmeal. Just think of that pizza, salad, birthday cake, all mushed up together. Yummy!

Then after another hour or so, I have the mush turned into a…

SLUSHY!

Then I open up my secret passageway, called the pyloric sphincter, and send that ooey gooey icky bicky mess to the duodenum.

Now sometimes things don’t go this smoothly. For example, my mucus lining might get too thin and the acid will get through it and completely erode my wall. Ouch!

This is called an ulcer. And they can even bleed. Now that really freaks the doctors out.

Scientist think that stress or bacteria causes this to happen. Also might food might disagree with me, and then some really wild things might happen …

But let’s not talk about that.

So as you can see, I have a very important job. Most people highly appreciate me.

The duodenum is shaped liked a small horseshoe, and is about 8 inches long. Like the rest of the digestive system, the duodenum is made of many layers.

In the duodenum the layers longitudinal and circular muscles contract and relax regularly. This is because food is moved along by peristaltic waves. The mucus layer of the duodenum also contains glands that produce digestive juices.

When chyme enters the duodenum it’s very acidic, and if the chyme then continue to travel through the rest of the digestive system, the acid would cause much damage. Fortunately, chemicals produced in the duodenum help and neutralize the acid. Which make the chyme safe to continue moving throughout the digestive system.

A stomach enzyme called pepsin only works when it is in an acidic environment, so the alkaline nature of the duodenum stops it from breaking down proteins. Instead, glands in the walls of the duodenum make enzymes known as peptidases, which finishes the digestion of proteins, by grinding up polypeptides into small molecules.

There are other enzymes (produced in glands in the duodenum walls) called maltase and another called sucrace. These enzymes turn maltose and sucrose (these are types of sugars that the body can’t use) into glucose, which the body can use.

In the duodenum, digestive juices from the pancreas and liver are now mixed with the now-liquid food.

Juices from the liver enter the duodenum through small holes in the duodenum wall. This is controlled by a small ring of muscles called the Sphincter of Oddi

Bile is made in the liver and stored in the gallbladder. It plays an important part in the digestion of fats.

Pancreatic juice enters the duodenum and contains enzymes to break down fats, starch, and proteins.

The small intestine really is not small at all!

Actually it is REALLY long!

Between 18-22 feet long in an adult! That is like laying 22 notebooks down end to end!

And it is all packed beneath your stomach.

The small intestine is very important. Food that has been broken down into the smallest components, the nutrients——

——the good stuff——

are now ready to be absorbed by your body in the small intestine.

The food is squeezed through the small intestine like you squeeze your toothpaste.

There are tiny hairs that line the walls of the small intestine called villi.

Villi are sort of like doors in the wall of the intestine.

Food goes through the villi and out into your bloodstream.

The final stages of digestion takes place in the large intestine, which loops up, across, and down our body like a horseshoe.

Here, bacteria help to break down what’s left of the food.

The wall of the large intestine allows water and nutrients to pass through.

All that leaves the large intestine is waste.

So you see, it’s really important to put the right stuff into your body, because--

the right stuff will make you run right!