Name:______________________________ 3- ____

OUR DIGESTIVE SYSTEM: TURNING FOOD INTO FUEL

All food contains substances (materials) called nutrients. NUTRIENTS ARE CHEMICALS THE BODY USES TO STAY HEALTHY. Inside our bodies, the process of digestion breaks food down into particles much smaller than we could cut with a knife. Once food has been broken down (or digested) into small pieces, the nutrients from these foods enter the different kinds of cells in the body for energy, growth, and repair.

DIGESTION - The process of breaking down food into substances that can be used by the body.

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Salivary GlandsEsophagusLiver

StomachGall BladderPancreas

Small IntestineLarge Intestine

AppendixRectum

THE ROUTE OF THE DIGESTIVE SYSTEM:

Chewing also makes food safe and easy to swallow. After food has been chewed, you swallow it and it begins its journey through the rest of the digestive system.

system (tract) in much the same way. Muscles behind the food squeeze together while muscles in front of the food relax. In this way the action of the muscles forces the food through the esophagus and other parts of the digestive tract.

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Digestion begins in the mouth. The MOUTH breaks down food into smaller pieces being chewed by your teeth and moved around by your tongue. Saliva enters your mouth containing chemicals that “attack” foods to make them easier to digest.

When food is swallowed it moves through the esophagus. The ESOPHAGUS is a muscular tube that squeezes food from your mouth to your stomach. The journey of food through the esophagus is a short one, lasting only several seconds. But food doesn’t just fall down the esophagus. In fact, even if we chose to eat and swallow upside down, food would still quickly make its way to the esophagus – as well as the other parts of the digestive system because of the muscles contracting. Picture a tube of toothpaste. Squeezing the tube forces the paste out. Food moves through the digestive

In the stomach, food is turned into a kind of soupy mixture called chyme (prounounced “k-ime”).

After the stomach has performed its part of the job of digestion, chyme moves to the next station in the digestive system, the small intestine.

The SMALL INTESTINE absorbs nutrients and water from the broken down food. The small intestine makes up the largest part of the digestive tract. In some ways, the small intestine is like a coiled hose. If you could uncoil the small intestine like a hose, you would see it is surprisingly long; about 22 feet long. It usually takes at least six hours for food to travel that long, winding road. There, like a detergent, bile breaks up large particles of fat into smaller particles that are easier to digest.

The PANCREAS produces a chemical called insulin. Insulin helps our cells use the “sugars” in the food we eat so they can have energy to do their jobs. The wrong amount of insulin can cause a condition called diabetes.

Chemicals from the liver and pancreas squirt into the beginning part of the small intestine. The LIVER makes a greenish liquid called BILE which is sent to be stored until needed for digestion in the GALL BLADDER. In some ways, bile is like a soap detergent. A detergent helps wash dirty dishes or pans by breaking up fat and grease. Bile flows from the gall bladder through a tube into the small intestine. By now, the

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When food reaches the end of the esophagus, it goes into the stomach. The STOMACH further breaks down the food chemically (combining the food with chemical juices) and mechanically (by squeezing and turning the food).

Small Intestine

Large Intestine

food is pretty well broken down, as it is pushed along through the rest of the small intestine.

In this way, food finally gets where it is needed…to muscles, where it is used for energy, to bones where food helps make new bone cells needed for a person to grow… and to the brain, so we can take in information about the world around us and think.

By the time food arrives in the large intestine, digestion is nearly finished. Foods that cannot be digested are pushed into your large intestine. The main job of the LARGE INTESTINE is to absorb water, turning the soupy digested food into solid feces. Feces then builds up and is eliminated from the body through the RECTUM.

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There are millions of tiny hair-like fibers called VILLI which line the small intestine. An area the size of a postage stamp contains as many as 20,000 VILLI. VILLI are like the fibers on the surface of a fluffy towel. The VILLI wave back and forth, picking up nutrients and water from the chyme. The nutrients are then carried through the bloodstream to nourish all the cells of the body.

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THE ROUTE OF FOOD IN MY DIGESTIVE SYSTEM:

The digestive system’s main function (job) is to change food through mechanical (chewing) and chemical actions into a form the body can use. Using the underlined words in the text above, trace the digestive system from the beginning to the end:

M ___ ___ ___ ___ - The beginning of digestion. Teeth grind and tear food while the tongue moves food around (mechanical). Salivator glands secrete saliva to help moisten food to help with the beginning of breaking down food (chemical).

E ___ ___ ___ ___ ___ ___ ___ ___ - Muscular tube for food to travel between the mouth and the stomach.

S ___ ___ ___ ___ ___ ___ - Where food is changed into a soupy mixture called chyme through chemical and mechanical processes.

S ___ ___ ___ ___ I ___ ___ ___ ___ ___ ___ ___ ___- Where nutrients for the body are absorbed and moved into the bloodstream to reach all the cells of the body.

L ___ ___ ___ ___ I ___ ___ ___ ___ ___ ___ ___ ___ - Where water is re-absorbed into the body.

R ___ ___ ___ ___ ___- The lowest part of the large intestine where solid waste (called feces) is held until there is enough to be released from the body.

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IN ADDITION:

S__ __ __ __ __ __ __ G __ __ __ __ __ – releases saliva into the mouth. Saliva contains chemicals that makes food easier to digest.

L__ __ __ __ – Produces digestive juice called bile. Bile helps digest the fat in food.

G__ __ __ B__ __ __ __ __ __ – Stores bile until it is needed.

P__ __ __ __ __ __ __ – Produces a chemical called insulin. Insulin helps the cells break down “sugar” in food. If the pancreas does not work properly and does not produce enough insulin, the person may have the disease known as DIABETES.

A__ __ __ __ __ __ __ – A part at the beginning end of the small intestine and the beginning of the large intestine which has no known function (job).

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Diseases and conditions of the digestive system:

Diabetes – A disease in which a person has high blood sugar, either because the pancrease does not produce enough insulin, or because cells do not respond to the insulin that is produced. Symptoms may include frequent urination, increase thirst or hunger. A person with diabetes has to test their blood sugar throughout the day and may have to inject themselves with insulin.

Cancer – An abnormal growth of cells which prevents an organ from performing its function. Cancer can occur in any organ. Treatment can be in the form of surgery, radiation or chemotherapy.

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Appendicitis:

An infection of the appendix that usually requires the appendix to be surgically removed.

Dehydration:

Where the body does not receive enough liquids. Can cause headaches, stomach aches, chills.

Intestinal flu:

A virus that causes fever, chills, headache, nausea, diarrhea, vomiting.

Diarrhea:

A condition that causes loose (watery) bowel movements.

Constipation:

A condition that makes it difficult to have a bowel movement.

Ulcer:

A painful condition where there is a small hole in the stomach, esophagus or intestinal tract.

How to take care of the digestive system:

Eat enough fiber in your diet to help “move your bowels.” Fiber can be found in foods like fruits, vegetables and some cereals.

Drink 6-8 glasses of water per day to help stay “hydrated.”

Wash hands with soap and warm water after using the bathroom to remove bacteria and viruses that can cause illness.

Exercise 60 minutes a day.

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