Major Functions of the G.I. Tract

When we think of our G.I. tract we normally think of two things, eating and restroom habits, but the major functions of the G.I. Tract are digestion of food, this is where food particles are broken down and the other major function is absorption this is when food is transferred into the circulatory system to the cells for further use.

There are two parts to the digestive system:

Alimentary tract is a continuous tract from the mouth to the anus the food is taken in via the mouth and the waste products are then excreted via the anus.

Accessory Organs which are necessary for digestion but are not part of the G.I tract: liver, pancreas, gall bladder and salivary glands.

The various parts of the G.I tract include the mouth (oral cavity and tongue), teeth(incisors, molars and cuspids), salivary glands (parotid, sublingual and submaxillary), pharynx(nasal, oral, laryngeal), esophagus, stomach (fundus, rugae, cardiac sphincter and pyloric sphincter), small intestines (duodenum, jejunum and ileum) and large intestines (cecum, ascending, transverse, descending, sigmoid, rectum and anus).

The mouth aids in chewing, contains the taste buds, salivary glands moisten foods, begin the conversion of starches to sugars and lubricates the food as it travels through the G.I tract. The pharynx aids in the travel of the food while the esophagus secretes mucus to aid movement of food and serves in a passage way for food to enter the stomach. The stomach begins the digestion of proteins, serves as a reservoir for food for 3-4 hours and also turns solid forms of food into a semi-liquid form called Chyme. There are various gastric juices that the stomach excretes to aid in digestion and absorption of needed nutrients and vitamins. HCL is a strong acid that aids in the digestion of meats and protects us from foreign organisms, pepsin is for the digestion of proteins, intrinsic factor aids in the absorption of B12, mucin protects the stomach lining and water is a solvent that aids in digestion.

The small intestines are the longest part of the G.I tract and this is where 90% of digestion takes places. The wall of the duodenum secretes mucus to neutralize acids that occur from the stomach. The digestive juices excreted from the liver and pancreas also enter into the duodenum. Large intestines are where the re-absorption of water, vitamins and minerals occur, they also secretes mucus to aid in movement of feces.