How does the Digestive System Work

Food digestion is an important metabolic processes for survival. The food that we consume is not directly used by the body cells; rather it is converted into simpler usable forms through digestion, which is then distributed to the body parts. Hence, digestion is responsible for supplying energy to all the body cells and tissues. Since digestion of food takes place via the digestive system, maintaining a good digestive health is always recommended for normal functioning of the body.

The Digestive System

This system comprises the digestive tract (starting from the mouth and ending at the anus) and several other organs that help in the digestion process. The organs of the digestive tract are mouth, esophagus, stomach, intestine (small and large) and anus. During the process of digestion, the mucosa lining of the mouth, stomach and small intestine secretes enzymes that aid in the digestion of food.

The smooth muscle lining of the digestive tract also helps in the mechanical breakdown of the food. The organs, liver and pancreas produce digestive juices or enzymes that help in breaking down the complex food substances (e.g. fats and lipids) into simpler forms. Overall, this system works in coordination with the circulatory system and nervous system, for digestion and supplying energy to the body parts.

Detailed Working of The Digestive System

The actual working starts in the mouth when food is chewed and mixed with saliva. The salivary enzyme acts upon the starch contained in the partly broken food, thus converting it into simpler particles. The partly digested food after being swallowed, passes to the esophagus. In the esophagus, the rhythmic muscle movement or peristalsis directs the food particles towards the stomach.

As the food particles approaches the stomach, the lower esophageal sphincter (a partition between esophagus and stomach) relaxes, thus allowing the transfer of food to the stomach. Once food reaches the stomach, it is stored for sometime, and then mixed with the digestive enzymes secreted by the stomach. The muscle movement of the lower stomach does the function of mixing food particles and digestive enzymes. From the stomach, it is passed into the duodenum of small intestine.

The time required for transferring food to the intestine depends on the type of food. For example, carbohydrate is emptied very fast; whereas fats are stored for a longer duration in the stomach. The food particles after reaching the small intestine is acted upon by several digestive enzymes, namely, the pancreatic juice, bile and other digestive enzymes secreted by the mucosa lining of the small intestine. All these enzymes help in the digestion of food particles. The actual digestion process ends in the small intestine. The useful foods and/or nutrients are absorbed by the intestinal walls and are distributed to the body parts through the circulatory system.

The remaining food particles are transferred to the large intestine or colon. Further digestion takes place in the large intestine and the intestinal wall absorbs the useful nutrients. Finally, the solid waste and indigestible food particles are excreted by bowel movement. This way, the organs of the digestive system function in coordination during the digestion process.