DIGESTIVE SYSTEM Hi! I’m that bite of pizza you are about to eat. This is my journey through your body. Pizza Project Abigail Smith

MOUTH This is my least favorite part of the trip. Your teeth hurt me pretty bad, but they put masticate me into smaller pieces so you don’t choke. You may feel me on your hard palate and if you keep me too long on your soft palate, you may gag. The saliva in your mouth also helps the food to become moistened so the rest of the trip is easier.

PHARYNX After I get chomped up in your mouth, I enter the pharynx. I will enter the oropharynx first and then I will enter the laryngopharynx. As the muscles in the pharynx contract, they push me on into the esophagus below. This feels way better than your teeth.

ESOPHAGUS The walls of the esophagus are made up by 4 layers of tissue: mucosa, sub mucosa, muscularis externa, and serosa. The different tissues make it easier for me to slide right through on down to the stomach.

STOMACH I will now enter the C-shaped stomach. I will start by going into the cardiac sphincter. Then, I will go into the pyloric sphincter. When the stomach is full, it is holding about a gallon of food. I will stay here for a little while until I am ready to go into the small intestine. The stomach also helps break me down some more so the small intestine is ready for me. Nutrients and proteins begin to be found and broken down in the stomach as well. When it is empty, the stomach collapses inward into folds called rugae. I get squeezed in here but it’s not so bad.

In the stomach there are enzymes that help break the food down In the stomach there are enzymes that help break the food down. Chief cells produce protein-digesting enzymes called pepsogins. Parietal cells make hydrochloric acid when makes everything in the stomach acidic so the enzymes will become activated.

SMALL INTESTINE I then travel into the small intestine in the form of chyme which looks like heavy cream. It is a muscular tube that goes from the pyloric sphincter to the ileocecal valve. The small intestine is about 6 feet long. It contains 3 subdivisions that I will travel in: duodenum, jejunum, and ileum. Put together, these come to be about 21 feet long. Here, I will start to be chemically digested by the pancreatic duct and the bile duct. I will also be absorbed mostly here by the microvilli, villi, and circular folds.

Enzymes produced by intestinal cells and the pancreas that are ducted into the duodenum by the pancreatic duct finish off the chemical break down of the small intestine.

LARGE INTESTINE After the small intestine, I travel into the large intestine. The large intestine is actually shorter in length, but it is larger in diameter. The large intestine will absorb any of the water I held in so that I can make my way out of you. Certain parts of the large intestine are important so I’ll tell you a little more about them.

COLON There are 4 parts of the colon. ascending: on the right side, travels up transverse: goes across abdominal cavity descending: on the left side, travels down toward pelvis sigmoid: s-shaped part in pelvis

CECUM The cecum can be a very dangerous place if I’m not careful. I hope I make it through without causing a bacteria build-up. Since it’s such a small space, it is very easy to do. If I do cause a build-up, you will get appendicitis. Appendicitis is the inflammation of the appendix. We defiantly don’t want that to happen now do we?

ANUS Once I am completely done being digested, I will start to go down the anal canal. In the canal, there are two sphincters: external voluntary that is made of skeletal muscle, and internal involuntary that is made of smooth muscle. Those muscles work together to open and close to allow your feces out. (otherwise known as poop)

Too bad I don’t look like this anymore. YOUR TOILET I won’t explain what happens here. I think you know quite well. Too bad I don’t look like this anymore.

Other organs that take part in the digestion process: Pancreas – Produces enzymes that help break down food and produces insulin and glucagon. Liver – Produces bile that breaks down fatty substances into smaller ones which allow for more surface area. Gallbladder – Stores bile for the liver when it gets backed up.

CONCLUSION Your digestive system does a lot of work just in one day. It is a long process that requires everything to work together. If one thing does not function as it should, many things could mess up. Everything working together allows for a wonderful flow through your body. As food travels from the mouth all the way to the anus, it undergoes many changes. Proteins and nutrients are taken out and put into other places in your body to allow your body to function better. Liquids are taken out so that it is easier for you to let your food exit. Things are filtered and secreted everywhere. So next time, think about what you are eating because it really does affect your body!