Digestive System


     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 : Basic Information 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.