Lecture 10 digestive system
- 1. Health Education- The Digestive System Miss Chantelle Chaudoin MPH
- 3. The Digestive System The human digestive system is a complex series of organs and glands that processes food. In order to use the food we eat, our body has to break the food down into smaller molecules that it can process; it also has to excrete waste. Most of the digestive organs (like the stomach and intestines) are tube-like and contain the food as it makes its way through the body. The digestive system is essentially a long, twisting tube that runs from the mouth to the anus, plus a few other organs (like the liver and pancreas) that produce or store digestive chemicals.
- 4. The start of the process: The Mouth The digestive process begins in the mouth. Food is partly broken down by the process of chewing and by the chemical action of salivary enzymes (these enzymes are produced by the salivary glands and break down starches into smaller molecules).
- 5. On the way to the stomach: the esophagus After being chewed and swallowed, the food enters the esophagus. The esophagus is a long tube that runs from the mouth to the stomach. It uses rhythmic, wave-like muscle movements (called peristalsis) to force food from the throat into the stomach. This muscle movement gives us the ability to eat or drink even when we're upside-down
- 6. In the stomach The stomach is a large, sack-like organ that churns the food and bathes it in a very strong acid (gastric acid). Food in the stomach that is partly digested and mixed with stomach acids is called chyme.
- 7. In the small intestine After being in the stomach, food enters the duodenum, the first part of the small intestine. It then enters the jejunum and then the ileum (the final part of the small intestine). In the small intestine, bile (produced in the liver and stored in the gall bladder), pancreatic enzymes, and other digestive enzymes produced by the inner wall of the small intestine help in the breakdown of food.
- 8. In the large intestine After passing through the small intestine, food passes into the large intestine. In the large intestine, some of the water and electrolytes (chemicals like sodium) are removed from the food. Many microbes (bacteria like Bacteroides , Lactobacillus acidophilus , Escherichia coli , and Klebsiella ) in the large intestine help in the digestion process. The first part of the large intestine is called the cecum (the appendix is connected to the cecum). Food then travels upward in the ascending colon. The food travels across the abdomen in the transverse colon, goes back down the other side of the body in the descending colon, and then through the sigmoid colon.
- 9. The end of the process Solid waste is then stored in the rectum until it is excreted via the anus.
- 11. Vocabulary anus - the opening at the end of the digestive system from which feces (waste) exits the body. appendix - a small sac located on the cecum. ascending colon - the part of the large intestine that run upwards; it is located after the cecum. cecum - the first part of the large intestine; the appendix is connected to the cecum. descending colon - the part of the large intestine that run downwards after the transverse colon and before the sigmoid colon.
- 12. Vocabulary duodenum - the first part of the small intestine; it is C-shaped and runs from the stomach to the jejunum. esophagus - the long tube between the mouth and the stomach. It uses rhythmic muscle movements (called peristalsis) to force food from the throat into the stomach. gall bladder - a small, sac-like organ located by the duodenum. It stores and releases bile (a digestive chemical which is produced in the liver) into the small intestine.
- 13. Vocabulary ileum - the last part of the small intestine before the large intestine begins. jejunum - the long, coiled mid-section of the small intestine; it is between the duodenum and the ileum. liver - a large organ located above and in front of the stomach. It filters toxins from the blood, and makes bile (which breaks down fats) and some blood proteins. mouth - the first part of the digestive system, where food enters the body. Chewing and salivary enzymes in the mouth are the beginning of the digestive process (breaking down the food).
- 14. Vocabulary pancreas - an enzyme-producing gland located below the stomach and above the intestines. Enzymes from the pancreas help in the digestion of carbohydrates, fats and proteins in the small intestine. rectum - the lower part of the large intestine, where feces are stored before they are excreted. sigmoid colon - the part of the large intestine between the descending colon and the rectum.
- 15. Vocabulary stomach - a sack-like, muscular organ that is attached to the esophagus. When food enters the stomach, it is churned in an acid bath. transverse colon - the part of the large intestine that runs horizontally across the abdomen.