Digestion is the process by which your body breaks down food into smaller chemical compounds. It's necessary because the body needs the food in smaller molecules of nutrients before it can be absorbed into the blood. You can't feel yourself digesting the food, but you know it's happening because when you excrete it back out, it looks different. So how does it all happen?
             It begins in your mouth. When you chew on the food, you break it down into smaller pieces so you can swallow. Saliva also helps out by breaking down the food further and it makes the food mushy and easier to swallow. This step should only take a few seconds to complete. The windpipe is also at the back of the throat, so when you swallow, a small flap of skin closes up the windpipe. Sometimes, when you swallow, the flap doesn't have enough time to close and you choke on your food.
             When you swallow, the good goes through your esophagus. It goes through by peristalsis, which is made up of muscles which causes waves that push the food through. This is why you can swallow even when you're upside down and gravity won't pull the food back out. A valve that opens up to allow food to pass through leads to the stomach where the next step takes place. This also takes several seconds.
             Inside the stomach, the food is mixed with gastric juices inside the stomach. Those gastric juices break down the food and create a liquid mixture. The muscles inside the stomach churn the gastric juice and food together. This step can take up to three and a half hours. The stomach then pushes the food into the small intestines.
             The small intestines are actually a lot longer than the large intestines, but the large intestines are thicker. The small intestines separate the food into several different categories like fats, carbohydrates, minerals, proteins, and vitamins. It does this with the help of your gallbladder, liver, and pancreas. The p...