D I G E S T I V E S Y S T E M
O V E R V I E W :
On this page you will learn about the Digestive System, which break down foods in to smaller pieces, so they can be used as an energy source for the body.
C O N T E N T S :
The digestive system contain organs for changing food chemically for absorption by body tissues. It is also responsible for processing food , breaking it down into usable protein, minerals, carbohydrates and fats and other substance. The digestion process involves breaking food into simple soluble substances absorbable by tissues.
The digestion process includes both mechanical and chemical processes. The mechanical processes include chewing to reduce food to small particles, the churning action of the stomach, and intestinal peristaltic action. The three chemical reactions take place : conversions of carbohydrates into such simple sugars as glucose, breaking down of protein into such amino acids as alanine, and conversion of fats into fatty acids and glycerol. These processes are accomplishes by specific enzymes.
The Digestive Journey
The digestive process starts in your mouth when you start eating. The salivary glands produce secretions that are mixed with the food. The saliva breaks down starches into dextrin and maltose. Then it goes down your esophagus in peristaltic waves to the stomach. This only takes the matter of seconds. The stomach contains gastric juice and the gastric juice contains chemicals such as hydrochloric acid and some enzymes, including pepsin, rennin, and lipase.
Pepsin breaks proteins into peptones and proteoses. Rennin separates milk into liquid and solid portions and lipase acts on fat. Another function of stomach digestion is gradually to release materials into the upper small intestine, where digestion is completed.
After the solid food has been digested the fluid remaining is called chyme When it is thoroughly digested it pass through the pylorus sphincter to the small intestine. Here in the small intestine all the nutrients are absorbed from the chyme into the bloodstream leaving the rest or the unusable residue. The residue pass through the colon or large intestine to the rectum. The solid waste, called feces pass through the anal canal and the anus.
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