Shaunquetta N. Johnson
Digestion begins when food enters the mouth and is chewed and swallowed. Parts of the digestive system work together to chop, churn, and squeeze the nutrients from food. Nutrients become energy for the body to grow, and to fix broken bones and torn tissue. The teeth tear and grind food to mix with saliva (spit). The enzymes in saliva help break down food, making pieces of food easier to swallow. The tongue pushes food from the mouth to the esophagus, a 10 inch tunnel. The muscles surrounding the esophagus squish the mushy food to the stomach. A small flap covers the windpipe that keeps food and liquids from going the wrong way. If food or liquids slip into the windpipe, the body coughs it out quickly. The stomach stretches like a balloon to hold food and the stomach's wrinkled walls unfold as food slide in. Muscles wrap around the stomach in different directions that squeeze, twist and crunch food. Muscles also mix in gastric juices that process food into a thick soup. Slimy mucus protects stomach walls from gastric juices. The stomach churns a meal for about 4 hours into a soup-like mixture. The mixture oozes into the small intestine, a 20 foot (6 meters) tube. Enzymes break off food's tiny nutrients that pass through the intestinal walls and into the blood. Unused food moves into the large intestine which is much shorter than the small intestine, but is twice as wide. The large intestine connects to the rectum which pushes out feces or gas. The liver aids in digestion by making bile which squirts into the small intestine to digest fatty foods. The liver receives nutrients from the small intestine to make proteins. Additionally, the liver cleans the blood and removes poisons (drugs and alcohol) from the body
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