What Is Digestive System

What is the digestive system?


 The digestive system is made up of the gastrointestinal tract, also called the digestive tract, and the liver, pancreas, and gallbladder.  The gastrointestinal tract is a series of hollow organs joined together in a long, twisted tube that runs from the mouth to the anus.  The hollow organs that make up the gastrointestinal tract are the mouth, esophagus, stomach, small intestine, large intestine, and anus.  The liver, pancreas and gallbladder are the solid organs of the digestive system.


 The small intestine has three parts.  The first part is called the duodenum.  The jejunum is in the middle and the ileum is at the end.  The large intestine includes the appendix, cecum, colon, and rectum.  The appendix is ​​a small finger-shaped sac attached to the cecum.  The cecum is the first part of the large intestine.  The colon is next.  The rectum is the end of the large intestine. 


Bacteria in the gastrointestinal tract, also called intestinal flora or microbiota, help with digestion.  Parts of the nervous and circulatory systems also help.  Working together, nerves, hormones, bacteria, blood, and digestive organs digest the food and liquids a person eats or drinks each day.


 Why is digestion important?

 Digestion is important because the body needs nutrients from food and drinks to function properly and stay healthy.  Proteins, fats, carbohydrates, vitamins NIH external link, minerals NIH external link, and water are nutrients.  The digestive system chemically breaks down nutrients into small enough parts that the body can absorb the nutrients and use them for energy, growth, and cell repair.


  •  Proteins are chemically broken down into amino acids


  •  Fats are chemically broken down into fatty acids and glycerol.


  •  Carbohydrates are chemically broken down into simple sugars.


How does the digestive system work?


 Each part of the digestive system helps transport food and liquids through the gastrointestinal tract, chemically break down foods and liquids into smaller parts, or both.  Once food has been chemically broken down into small enough parts, the body can absorb and transport the nutrients to where they are needed.  The large intestine absorbs water and the waste products of digestion become feces.  Nerves and hormones help control the digestive process.

How is food transported through the gastrointestinal tract?


 Food is transported through the gastrointestinal tract through a process called peristalsis. The large, hollow organs of the gastrointestinal tract contain a muscular layer that allows their walls to move. The movement pushes food and liquids through the gastrointestinal tract and mixes the contents within each organ. The muscle behind the food contracts and pushes the food forward, while the muscle in front of the food relaxes to allow the food to move.

 Mouth—Food begins to move through the gastrointestinal tract when a person eats. When a person swallows, the tongue pushes food down the throat. A small flap of tissue, called the epiglottis, folds over the trachea to prevent the person from choking and so food passes into the esophagus.


 Esophagus—Once a person begins to swallow, the process becomes automatic. The brain sends signals to the muscles of the esophagus and peristalsis begins.


 Lower esophageal sphincter—When food reaches the end of the esophagus, a ring of muscle called the lower esophageal sphincter relaxes and allows food to pass into the stomach. This sphincter usually remains closed to prevent what is in the stomach from flowing back into the esophagus.


 Stomach—After food enters the stomach, the stomach muscles mix the food and liquid with digestive juices. The stomach slowly empties its contents, called chyme, into the small intestine.


 Small intestine—The muscles of the small intestine mix food with digestive juices from the pancreas, liver, and intestine and push the mixture forward to continue the digestion process. The walls of the small intestine absorb water and digested nutrients into the bloodstream. As peristalsis continues, waste products from the digestive process pass into the large intestine.


 Large intestine—Waste products of the digestive process include undigested parts of food, fluids, and old cells from the lining of the gastrointestinal tract. The large intestine absorbs water and changes waste from liquid to feces. Peristalsis helps move stool into the rectum.


 Rectum—The lower end of the large intestine, the rectum, stores stool until it is pushed out of the anus during defecation.

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