Digestive System
Key Terms
Key terms are mechanical digestion, chemical digestion, mouth, teeth, saliva, amylase, bolus, esophagus, peristalsis, stomach, pepsin, chyme, duodenum, small intestine, villus, large intestine, liver, gallbladder, and pancreas. Mechanical digestion is the breakdown of large pieces of food into smaller pieces of food, this way, they can be swallowed and accessed by digestive enzymes. During Chemical digestion enzymes break down food into small molecules that can be used by the body. The mouth is where the food goes in, it is the first step in the digestive system. Teeth grind up food to the point that you can swallow it. Saliva moistens food, that way it is easier to chew. Amylase is an enzyme found in saliva, it starts to break chemical bonds in starches, this makes sugar. A bolus is the clump of food that goes down the throat. The esophagus is a tube connecting the throat and stomach. Peristalsis are the muscles that move the bolus down the esophagus. The stomach is a muscular sac that continues the mechanical and chemical digestion. Pepsin is an enzyme that breaks proteins into smaller polypeptide fragments. Chyme is an oatmeal-like mixture, it is what the food becomes when it is mixed with hydrochloric acid and pepsin. The duodenum is where most of the digestive enzymes enter the intestine. The small intestine is where most of the chemical digestion and absorption of food occurs. Villi contain microvilli, they move the chyme while the microvilli move absorb nutrients. The large intestine, aka colon, removes water from undigested material. The Liver assists the Pancreas in digestion of fats, and the liver uses bile. The Gallbladder is a sac of bile. The pancreas breaks down carbohydrates, proteins, lipids, and nucleic acids. The pancreas also produces hormones that regulate blood sugar levels, it also produces a carbonate.
Digestive System Diseases
- celiac disease-A reaction to gluten
- inflammatory bowel disease-Small or Large intestine becomes inflamed.
- irritable bowel syndrome-When food moves throught the colon at an abnormal speed.
Video
The digestive system is what the food you eat goes through. When food enters your mouth it starts its journey through the digestive system. This video also includes information on the purpose of the appendix.
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Resources
Crash Course. “The Digestive System: CrashCourse Biology #28.” Online video clip. Youtube. Youtube, 6 Aug. 2012. Web. 25 Feb. 2015.
Miller, Kenneth R., and Joseph S. Levine. "30 Human Body." Biology. Upper Saddle River, NJ: Prentice Hall, 2000. 875-81. Print.
Villarreal, Mariana R. Digestive System Diagram. Digital image. Wikipedia. Wikipedia, 17 Dec. 2006. Web. 8 Mar. 2015. <http://en.wikipedia.org/wiki/Human_d
Miller, Kenneth R., and Joseph S. Levine. "30 Human Body." Biology. Upper Saddle River, NJ: Prentice Hall, 2000. 875-81. Print.
Villarreal, Mariana R. Digestive System Diagram. Digital image. Wikipedia. Wikipedia, 17 Dec. 2006. Web. 8 Mar. 2015. <http://en.wikipedia.org/wiki/Human_d