The food we eat provides the energy we need for our bodies to function and the building blocks our bodies and cells need to grow. Our digestive system is a network of processes and organs that helped turn our food into the fuel used on a cellular level. Our digestive system begins working as soon as food, like spaghetti and veggie-meatballs enters our mouth. The saliva begins the chemical breakdown of our food and chewing begins the mechanical breakdown of food. Although saliva is made up of mostly water it contains enzymes like amylase which begins breaking down starch like spaghetti noodles, and lipase which begins breaking down the fat ( or veggie cheese) in our food. When you swallow, your food moves down your throat to your stomach through a flexible tube called the esophagus. The esophagus sits right behind your trachea which carries air to your lungs. The epiglottis is a small flap that closes the trachea so food doesn't go down the wrong tube. The food moves down the esophagus via peristalsis, which is the muscles of your organ contracting and relaxing on their own to push the food forward. It's like the muscles are squeezing and then releasing the (now mushy) spaghetti. Once it enters your stomach the mechanical break down continues as food is sloshed back and forth into even smaller pieces. Your stomach's job is to mix and crush the food using peristalsis and hydrochloric acid (aka stomach juice).
This mushy food is now called chyme and it begins to be pushed into the small intestine where the nutrients will be sucked out of it. Although it's called the small intestine, it's actually 20 feet long, about 15 feet longer than the large intestine, but it is skinnier. Enzymes from the pancreas, and bile from the liver and gallbladder mix with the chyme to help liquefy it in the first part of the small intestine called the duodenum. Enzymes are proteins our bodies use to make chemical reactions that change one thing to another. For instance, certain enzymes change the juice in an apple to a simple sugar that our cells can use. As the food moves forward into the jejunum the nutrients begin to be absorbed by the intestinal walls. Once it moves into the final area of the small intestine the bile acids are returned to the liver to be stored and made into more bile to be used for your next meal. From the small intestine the peristalsis continues and the food moves into the large intestine also called the colon. The large intestine sucks up most of the water from the food and sends it into the our bloodstream to go throughout our body. What's left over gets passed out of our body into the toilet through the rectum.