La Casa De Comida - In the Zoo - The Digestive System - How Does the Digestive System Work?

La Casa De Comida : In the Zoo : The Digestive System : How Does the Digestive System Work?

How Does the Digestive System Work?

Digestion is the process by which complex, insoluble foods are changed into simpler, soluble materials which the body's cells can use.

The digestive system is the tube into which various digestive juices are poured at specific points to allow this digestive process to occur.

The mouth is the entry to the digestive system. Food enters the mouth where teeth hold, tear and grind food. The tongue is responsible for moving the food around the mouth. Saliva then starts to chemcially digest the food, turning in into a watery mixture that can easily pass into the stomach.
The throat is a connecting tube between the mouth and the esophagus, which in turn links to the stomach. The tonsils are at the enterance of the throat, and can become inflammed in a condition known as tonsilitis. Food is carried along the esophagus by muscular contractions called peristalsis.

Food is stored and digested in the stomach. The stomach contains hydrochloric acid and other important enzymes which chemically break down the food, releasing the nutrients. Muscular contractions move the partially digested food around the stomach.

Nutrients are absorbed in the small intestine. Divided into three sections, the small intestine continues to break down the food and releases the nutrients into the bloodstream so they can be passed around the body. It has a very large surface area due to the villi along its walls which help absorption.

The liver processes and distributes nutrients. The liver creates bile, which is important in chemically breaking down the food in the small intestine. It also processes damaged red blood cells and stores vitamins A and D. When there is no food in the small intestine bile from the liver is sent to the gall bladder where it is stored in a concentrated form, to be released when food enters the digestive tract.

The pancreas produces pancreatic juice. The pancreas makes enzymes which are released into the small intestine to break down the food. It neutralises the hydrochloric acid from the stomach, makes the enzyme to stimulate the liver into producing bile and secretes insulin which transports sugar.

Faeces are stored and expelled by the large intestine. Bacteria in the large intestine act on the waste product while water and some salts are absorbed through the intestinal wall. The remaining product is faeces, a combination of bacteria, undigested food and other waste products. The appendix is found off the large intestine.

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