GASTROINTESTINAL SYSTEM - AN INTRODUCTION -LESSON 55

DIGESTIVE SYSTEM:  INTRODUCTION TO THE DIGESTIVE SYSTEM: Digestive system is also called gastrointestinal system or alimentary canal. Digestive tract starts from the mouth and ends at the anus. Food enters into the body through the mouth and then enters into the intestines, after the food material absorbed, and the waste material excreted out from the anus.

Travel track of food materials:

Food travel starts first from mouth to pharynx to esophagus to stomach to duodenum where gallbladder, liver, and pancreas take part in the travel of the food then to jejunum to ileum to cecum to ascending colon to transverse colon to descending colon to sigmoid colon to rectum to anus.

What happens to the food as travels when enters into the GI (gastrointestinal tract)?

The food enters the body as a complex food material, we chewed the food, the saliva mixed with the food. The complex food material broken down into simpler material. The food material chemically and mechanically broken down. These processes happen as the food travels from the mouth to the intestines.

The complex food materials broken into simpler amino acids. The complex glucose or sugar material in the food broken into simpler sugars, and also the large triglycerides made up of fat molecules are broken down into glycerol and simpler fatty acids. This process is called catabolism.

The food now digested and the digested food must be absorbed in the bloodstream in this stage. This process is happened when the food in the small intestine absorbed by the walls of it.

These energy particles in the food such as catabolized nutrients in the blood such as amino acids, glucose, triglycerides, and glycerol and burnt in the presence of oxygen and energy stored in the food is released.

Body cells in this stage use the simple amino acids to build again large proteins. This process is called anabolism. These large proteins take important place in growth and development of the body. The rest of the fatty acids and glycerol absorbed by the small intestine entered now into the lymphatic vessels, not into the bloodstream. Lymph vessels and blood vessels join together in the chest area of the body and the fat materials digested enter into the blood.

The solid waste materials in this stage eliminated from the body as these materials cannot be absorbed by the blood. These materials now entering into the large intestine. This solid waste is called feces. The feces is then excreted out from the body through the anus, a small opening.

In the next lesson we will see about ANATOMY AND PHYSIOLOGY OF THE GASTROINTESTINAL SYSTEM..okay


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