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The Digestive System By, Rachel Lieberman June 26, 2007 What is the digestive system? The digestive system is a group of organs that break down food into a form that the body can use. All people need the nutrients found in food. The digestive system breaks down food to release these nutrients. These nutrients give us energy and keep us healthy. After you take a bite, food travels through about 30 feet of digestive organs!!! http://www.nlm.nih.gov/medlineplus/ency/imagepag es/1090.ht Digestion in the Mouth http://www.orthop.washington.edu/_Rainbow/Album/10357m303553449190-45c7-9cdc-c591f8b17bb5.gif Digestion begins before you put food in your mouth. When you see or smell food, your salivary glands begin to work. Your salivary glands produce saliva, which is a watery liquid that moistens your mouth and food. Every day, you produce as much as 6 cups of saliva!!! Inside saliva, there are enzymes. Enzymes are chemicals that help to break down your food. Teeth Your teeth help to break down food. There are 4 main types of teeth. Your incisors (front teeth) are the cutting teeth. They bite off a piece of food. You have canine teeth on each side of your incisors that cut and tear food. You have premolars and molars that help to grind your food up. http://www.kidshealth.org/kid/body/teeth_noSW.html Swallowing Once your food is chewed and mixed with saliva, you swallow. Stages of Swallowing: 1) The tongue pushes your food to the back of your throat. 2) A flap of tissue closes the trachea (tube that takes air into the lungs) 3) Throat muscles squeeze food to the top of the esophagus. 4) The flap of tissue rises that goes to the trachea (so you can now breath again). Esophagus The esophagus is a muscular tube that carries food from your mouth to your stomach. The food moves using a wavelike motion called peristalsis. Rings of muscles tighten above the food, forcing it down to the stomach. http://www.sts.org/images/esophbig.jpg Stomach http://www.healthnewsflash.com/images/conditions/stomach.jpg Food goes from the esophagus to the stomach. The stomach is a muscular organ that helps digest food. Food stays in the stomach for 2 to 6 hours where it mixes with acid…breaking it down. The acid in your stomach is strong enough to dissolve metal!!! Your stomach has a protective coat of mucus around it so the acid doesn’t burn through your organ! Food turns into a gross soupy liquid called chyme. Small Intestine Chyme leaves your stomach and travels to your small intestines. The small intestine is the long, coiled organ where most digestion takes place. The small intestine is NOT SMALL!! It can be about 20 feet long. It is all coiled up to fit in our bodies. The small intestine is called small because it is narrower than the large intestines. This organ produces more digestive juices and enzymes that keep breaking down food. The small intestine works with other organs suchas the liver, gallbladder, and pancreas, which help to break down food. How does the body pull out nutrients from this soupy mess? In the wall of the small intestines are villi. These are tiny blood vessels that line the inside of the small intestines. Dissolved nutrients pass into these villi as they go through the tubes and from here the villi send the nutrients to the blood. The blood carries the nutrients to the rest of your body. Large Intestines (Colon) After food goes through the small intestines, there is still some stuff left that the body did not absorb. This undigested stuff goes to the large intestines also known as the colon. The main role of the colon is to absorb any water or salt from the undigested material. It gives the water and salt to the body, and whatever is left over is removed from the body. About 1 to 2 days after you eat your meal, the undigested materials will pass out of your body. http://www.nlm.nih.gov/medlineplus/ency/images/ency/fullsize/9206.jpg When Digestion goes Wrong… Choking – If you talk or laugh while eating, the automatic process of swallowing may fail. Food can enter the windpipe (trachea) which stops you from breathing. A person trained in the Heimlich maneuver can help to get the stuck food, free. Ulcers – An ulcer is a small hole or erosion in the stomach or intestines. They can be up to ¾ inch wide. The mucus lining is damaged or dissolved by the hydrochloric acid in the stomach. Another major cause of ulcers is the chronic use of anti-inflammatory medications, such as aspirin. Cigarette smoking is also an important cause of ulcer formation and ulcer treatment failure. These ulcers cause a lot of pain. Stomach Ulcer Heimlich Maneuver