Hi…I am a piece of cake. I want to start my journey into the digestive system of a small boy. It's a hard journey that goes over long distances and can take several days. But it is OK. I will be useful for him as a source of his energy.
My journey starts when I was chewed by him. I was bathed by his saliva that comes out from his saliva glands. I turn into small pieces and my starch begins to turn to sugar! Wow….there is a long pipe. Do I have to enter it? Yes….it is his throat. What is this? I get a muscle squeeze, wave-like contraction and it pushes me down into a tube called esophagus. This squeeze is called peristalsis.
I am in the stomach now. This is another place after esophagus. Stomach is like a bag. It contains a lot of digestive juices like acids and enzymes. That’s why I become smoother and it helps stomach to break me down into smaller part and into a thick liquid or paste. This thick liquid or paste is called chyme. In this place I get another digestive chemical.
It is time to go into small intestine. This is a place where the nutrients of me absorb by millions of villi, the finger-like objects and send me into the blood stream then continue my travels to all the body cells.
Some of me do not useful; it is my leftover which is undigested. Therefore, I have to go to the large intestine. It is quiet different from small intestine. It is wider and drier. My water is extracted and it is reused back into his body. I was a liquid paste before but now I change into the solid waste. Then, my parts were collected in the rectum as the end of large intestine. When the time comes, I have to leave his body by his anus. Now, my long journey is over.
4. Food passes through the mouth, esophagus, stomach, small intestine, large intestine, rectum, and out the anus.
5. The digestive system breaks down food two ways:
mechanical digestion- the chewing (in the mouth) and churning (in the stomach)
chemical digestion- with the help of enzymes, into substances that cells can absorb and use. This occurs in the mouth, stomach and small intestines.
6.Once food gets partially broken down in the stomach, it becomes a thin watery liquid called chyme.
7. The pancreas releases digestive enzymes into the small intestines.
8. The large intestines absorb water from chyme so it can be used by the body.
9. Food moves past the mouth to the esophagus by gravity and peristaltis which is a squeezing action by smooth muscles.
http://web.jjay.cuny.edu/~acarpi/NSC/images/digestive.jpg
http://www.leeds.ac.uk/chb/lectures/anatomy8.html
http://vilenski.org/science/humanbody/hb_html/digestivesystem.html
http://www.imcpl.org/kids/guides/health/digestivesystem.html
