The Digestive System

The Digestive System
Anwar Brown
The digestive system is where ingested food is broken down and absorbed through physical and chemical processes in the body. The function is to provide the body with nourishment as well as to help excrete waste materials. This system is composed of the digestive tract which extends from the mouth to the anus. Digestion relies on assistance from parts of the nervous and circulatory system which releases hormones and enzymes. Digestive system involves breaking down large molecules into smaller molecules through various processes such as digestion, absorption and assimilation.
The act of digestion starts when food is swallowed through the mouth and transported to the esophagus as a bolus. The salivary glands react with the food to digest starch which breaks it down to glucose. Then it is passed through the esophagus down to the stomach by peristalsis and the enzymes in the stomach digest protein from it. Also, enzymes from both the pancreas and liver break down the carbohydrates, proteins and fats into simpler molecules.

The food becomes dissolved in the juices from the digestive organs and then is directed through the intestines. Any waste material such as fiber and other undigested products are sent into the colon and which are excreted by bowel movement. The process of absorption mainly takes place in the small intestines where molecules of food, water and minerals are absorbed. It involves four procedures which are active transport, passive diffusion, endocytosis and facilitated diffusion that absorb nutrients into the body. The small intestine has the villi which allows for absorption of nutrients and specialized cells release them into the bloodstream for storage.

Carbohydrates are composed of starch and sugar which are broken down into simple molecules like glucose, fructose and lactose by facilitated diffusion. Proteins are necessary to...