The Digestive System What ’ s really happening to the food that we eat?

Think about this… Just like a car needs fuel to go… …Our bodies need food to keep working.

However, We ’ ve got a problem… Most food that you eat is too big and complex for your tiny cells. That ’ s when the Digestive System comes into play.

What is Digestion? Digestion-breaks down food into smaller and simpler substances that your body can absorb.

WHISPER TO YOUR NEIGHBOR What does Digestion do? What does Digestion do? It breaks down food into smaller and simpler substances that your body can absorb.

Let ’ s take a journey through our body to see where our food travels…

1 st Stop…The MOUTH!

What goes on in the mouth? What goes on in the mouth? When you first eat your food, it goes straight into your mouth! The mouth and teeth are the first steps in breaking food down. The mouth supplies chewing and our tongue is used for tasting.

Let ’ s pretend you are going to Let ’ s pretend you are going to take a great big bite of an apple. take a great big bite of an apple. Once you take that bite…your teeth start tearing through the apple skin and grind the apple into a ball of food (also known as bolus).

When the apple touches your tongue, your taste buds tell you it is sweet. The salivary glands in your mouth and throat produce a watery fluid called saliva. Saliva helps to moisten and soften the bolus and break it down chemically.

Now that our food is all chewed up… Our tongue moves the chewed up apple to the back of our mouth and we… SWALLOW IT!

Mouth- The teeth grind up the food. Salivary glands in your mouth produce saliva which softens the bolus (ball of food) and breaks it down chemically.

2 nd Stop…The Esophagus

What does the esophagus do? When you swallow your food, it goes down your esophagus. Your esophagus is a tube that is about 10 inches long that connects your mouth to your stomach.

Esophagus- a tube that connects the mouth to the stomach.

“ Wait… what are the first two organs in the digestive system? Point to them and tell me them. ” The MOUTH and the ESOPHAGUS!

Nice Job! What comes next?

10 seconds later…3 rd Stop… the STOMACH!

The Stomach… When food enters the stomach, the muscles in the stomach contract and relax to create movement. Then in the stomach acids and digestive juices transform the food into a liquid substance.

Think about it this way… Think about mixing the ingredients to make a cake. You take a spoon and start stirring the ingredients creating a movement that resembles the contraction. It isn ’ t until you add a liquid substance (egg/oil) that the ingredients begin transforming into a liquid substance.

Stomach- The walls of the stomach have glands which produce acids and mucus. The muscles of the stomach contract and create a movement. The muscles squeeze and mix the bolus until it is changed into a thick liquid.

After about 4-6 hours later of mixing and squeezing, the liquid is released into the….

4 th Stop…Small Intestine 4 th Stop…Small Intestine

The Small Intestine Okay…Now our bolus has transformed into a liquid substance. Here in the small intestine, chemicals from the pancreas and the liver continue to mix with the bolus. The digestive juices break down the nutrients from the food into smaller, simpler forms. The nutrients are absorbed by the small intestine. The nutrients pass through the walls of the small intestine into tiny blood vessels that are transported throughout the body. food passes into the bloodstream through the villi, which line the small intestine walls, and are transported throughout the body.

Small Intestine- A coiled, tubular organ that breaks down the food mixture so your body can absorb all the nutrients through tiny hairs called villi.

WHISPER TO YOUR NEIGHBOR What are the first 4 organs in the digestive system? What are the first 4 organs in the digestive system? The mouth, esophagus, stomach, and small intestine.

But wait…what happens to the food that I couldn ’ t digest? 5 th Stop… The LARGE INTESTINE!

Large Intestine Cont. The parts of the apple that you could not digest move into the large intestine. The large intestine is a thick, tubular organ that removes undigested waste.

Large Intestine- A thick tubular organ that removes undigested waste.

6 th Stop… The Rectum 6 th Stop… The Rectum Solid waste called feces is eliminated from the body through the rectum.

Rectum- Small waste called feces is eliminated from the body.

“ Wait… what is the order the organs in the digestive system? ” The mouth, esophagus, stomach, small intestine, large intestine, rectum. The mouth, esophagus, stomach, small intestine, large intestine, rectum. Think: MESSLR Think: MESSLR

Now that we know how the Digestive System works… Let ’ s put it into action.