Digestion by

Food: A Cheeseburger

tldcampbell389 — 2017-04-15 00:56:54 UTC

- The bun contains carbohydrates
- The meat contains proteins
- The cheese contains lipids (fat)

Part One: Ingestion

tldcampbell389 — 2017-04-15 00:59:09 UTC

One day, Mr. C.H Burger decided to go on a vacation. His job was very stressful and he needed some time off. To reach his chosen destination he had to pass through the Digestion System, a confusing highway of intricate roads and pathways. Before he left, he decided to send home a picture to his family of every interesting place he saw in the Digestion System. These communications are included below.
1. The Mouth
When I reached the mouth, I was crushed into smaller pieces by the teeth. My presence in the mouth triggered the salivary glands to secrete saliva, which is a watery fluid which contains enzymes that increase the chemical reactions in me. A particular enzyme found in saliva is amalyse, which breaks down starches in me into disaccharides. Funny thing is, one function of saliva is to dissolve food particles so the human can taste them. Saliva also contains mucus, which lubricates the chewed up parts of me and makes them easier for the human to swallow. Once I have been mixed with saliva, the human's tongue pushes me towards the back of the mouth. This is quite fun! Almost like an amusement park ride! As I am pushed into the pharynx (which is the part of the throat behind the mouth and nasal cavity and before the esophagus) the soft palate raises up to make sure I do not go in the nasal passage and the larynx also rises up to prevent me from going in the trachea, because that would cause the human to choke. There are so many roadblocks on other routes making sure I go in the right direction.

tldcampbell389 — 2017-04-15 01:24:45 UTC

2. The Esophagus-
After I traveled out of the mouth, it was time to make my way down the Esophagus. The Esophogus is a useful pathway. It is a long muscular tube that carries food into the stomach. I move along it by muscular contractions called peristalsis.

Part Two: Digestion

tldcampbell389 — 2017-04-15 01:36:42 UTC

3. The Stomach
After I moved out of the Esophagus pathway, it was time to head down to the stomach. My time in the stomach further advances the digestion that was started in the mouth. The only thing that is digested in the stomach is proteins, which begin digesting here. A few other of my good nutrients, carbohydrates and lipids, are not digested in the stomach. The stomach is made up of four layers, which each have their own special function, including secreting gastric juice, and housing nerves and blood vessels. The digestion process in the stomach begins when the nerves in the submucosa, a layer of the stomach, notices that I have arrived to the party and release a special hormone named Gastrin, which move gastric cells to the stomach where they release gastric juice. Gastric juice is mainly mucus with a bit of digestive enzymes and acid for a little kick! The inherently high PH of the gastric juice serves to kill harmful micro-organisms that I may have in me but makes the ideal environment for the activation of digestive enzymes such as pepsinogen. It also converts pepsinogen to its other form, pepsin, which starts breakdown of proteins into amino acids. What an amazing activity! I'm glad that the acids in the stomach help to digest me and help me on my way to the next destination.

tldcampbell389 — 2017-04-15 01:53:03 UTC

4. Small Intestine
Much of the digestion of the nutrients found in me happens in the small intestine. The small intestine is narrower than the large intestine, but it is longer. Lipids an carbohydrates found in me are digested here. My stay in the small intestine was quite lovely. Upon entering the small intestine, I first traveled into the duodenum, which is the first section of the small intestine. Enzymes are added to me here, which will help the digestion of me as I move along to my next destination. Some nutrients are absorbed in the second section of the small intestine, the jejunum, but most of the nutrients are absorbed in the ileum. The inner layer of the small intestine contains villi, which contain webs of tiny blood vessels called capillaries. The digested nutrients from me are carried into the bloodstream via these capillaries. The pancreas, gallbladder, and liver also aids the digestion process inside the small intestine.

tldcampbell389 — 2017-04-15 02:34:38 UTC

5. The Pancreas
While I was staying in the small intestine, I got to hear about the function of several helping organs from the locals. The pancreas secretes enzymes that further aid the digestion process of me. After chyme enter the duodenum, a hormone called cholecystokinin (CCK) is released by cells in the mucosa of the duodenum. CCK tells the pancreas to secrete enzymes that are vital in lipid, carbohydrate, and protein digestion in the small intestine. When chyme enter small intestine its PH is extremely low, making it very acidic. The chemical prosecretin in the cells of the small intestine are converted into Secretin, which is a hormone which stimulates pancreatic and bile secretions.
Its primary function is to force the pancreas to release bicarbonate ions, which neutralize the chyme and raise its PH. This makes sure the small intestine is protected from stomach acids.
After this, protein digestion is carried on with. The pancreas secretes trpysinogen, a inactive form of the enzyme trypsin, which digests proteins. Another enzyme named enterokinase converts it into its active form.
The digestion of lipids is also continued. Fats entering small intestine are digested by an enzymes called lipases.

tldcampbell389 — 2017-04-15 03:08:21 UTC

6. The Liver and Gallladder
In my travels, I also got to learn about the helpful function of the liver. The liver secretes bile, which breaks down fat. The liver produces bile, but it is stored in the gallbladder until food like myself needs to be digested. Since all blood that goes through capillaries of intestines passes through the liver before returning to the heart, the liver helps filter and breakdown toxins from the blood.

tldcampbell389 — 2017-04-15 03:16:44 UTC

Part 3: Absorption

tldcampbell389 — 2017-04-15 03:17:47 UTC

7. The Small Intestine
After being digested I was almost done mu journey. One of the steps that was left was my nutrients being absorbed into the body. What a trip this has been! Nutrients are absorbed in the small intestine by both passive and active transport. They are absorbed with diffusion in passive transport by traveling across the concentration gradient from an area of higher concentration to an area of lower concentration. This is how nutrients enter the lining of the small intestine. Some of the water is absorbed into cell membrane of small intestine by osmosis, where water molecules move from area of higher concentration to area of lower concentration. Facilitated diffusion moves molecules across a membrane with help of transport proteins. Some of my nutrients are also absorbed using active transport. This is when materials are moved across the membrane if the small intestine using energy provided by the cell.

tldcampbell389 — 2017-04-15 03:32:23 UTC

8. The Large Intestine
Next, the waste parts of me after digestion were sent on to the large intestine. The colon is the longest part of the large intestine. The rectum is situated at the end of the anus. It holds waste products for elimination out of the human body by the anus. Once the digestion process reaches the large intestine, most of the nutrients have been absorbed in the small intestine. As the undigested materials pass through the colon, water is absorbed back into the body via digestion.

Part 4: Egestion

tldcampbell389 — 2017-04-15 03:39:37 UTC

9. Rectum and Anus
Egestion is the elimination of waste food materials from the human body. Water absorption in large intestine allows the waste materials to take on the form of feces. A defecation reflex is initiated once the feces moves into the rectum. Thus, the waste materials are successfully moved out of the human body. Thus ends my lovely trip. I was able to see many lovely sights, and I will return to my work rejuvenated.

Works Cited

tldcampbell389 — 2017-04-15 03:43:14 UTC

"Pharynx." Wikipedia. Wikimedia Foundation, 09 Apr. 2017. Web. 14 Apr. 2017. .

"Digestive System." InnerBody. N.p., n.d. Web. 14 Apr. 2017. .

http://www.enchantedlearning.com/subjects/anatomy/digestive/